Xray4
Cadet
- Joined
- Apr 22, 2020
- Messages
- 29
Hi everyone. Thank you for your participation in these forums. I've found it to be full of very helpful folks and I've learned quite a bit. Your time here is helpful to people many years on, you may not know the real extent of it. I've learned from posts that are 15 years old now. You rock. I hope you will be able to help me out. Below is a novel from the last week or so, and some background from the last two months. It's all there in case something jumps out at someone more knowledgeable than I.
I’m at a point where I have researched a lot of things related to this. From timing, to power pack, to fuel starvation and air in fuel. I know I should pull and clean the carbs for good measure and link/sync, but I am hoping someone will read this novel and something will stick out which you’d suggest I start with. I am in the travel industry and business has come to a complete standstill since March 1. I am now trying to very selectively troubleshoot/spend money on parts and tools as times are uncertain. I’d prefer not to just drop new parts left and right if it’s not going to solve the issue.
Please, someone if something in my novel strikes you, please help me out. I greatly appreciate you!
2001 Johnson 150 J150PLSIF sudden condition
Condition: WOT was 5250 with 14.5 x 17 prop, I thought that was correct. Mech says should be between 5000-5500. Idle seemed fine before. Last week like a switch was flipped: WOT dropped from 5250 to 4700, sounds fine just wont increase, just feels like it's at 3/4 throttle setting but it's actually maxed out. Cold start is still perfect, sounds fine, but dies at idle in gear after having been warmed and run. I don’t know the ground speed before the condition began, just the RPM, but with the condition, the groundspeed maxes at 34.2 mph, seems slower than before.
Background: This condition came on suddenly. It’s possible it’s related to some of the changes I’ve made due to the timing of them and the condition appearing, but I really don’t think the changes would cause the sudden condition. Please see below.
I got the boat 2 months ago in FEB 2020 in trade. It’s a 2000 22ft Lowe alum v deck boat. It’s an OIS setup. When I picked it up, it was on a trailer with the cover caved in and 16 inches of solid ice and snow melt on deck like a pool. Previous owner said carbs had been rebuilt in the last six months at a cost of ‘thousands’. I don’t have much to go on whether or not he is honest. Supposedly ran until 6 months ago, then wouldn’t run. My plan was to get her running, then do a complete rebuild of the boat. I brought it to a marine mechanic who found the VRO/fuel pump was shot. Mech. did the following: Reseal steering, flush, fill, bleed. R&R VRO, test,. Drain, flush, test alarm, install new oil, purge line oil tank. R&R Waterpump kit and gear lube, clean port temp sender for quickstart, new primer bulb, 2 case plug gaskets, repair trim leakdown issue. Compression came back: 1-121, 2-117, 3-120, 4-125, 5-115, 6-117. Total bill was $1850.. He suggested the following maintenance ‘when you get around to it’: sparkplugs QL78YC @0.30, H20 separator kit, throttle roller, prop, t-stat kits, fuel filter assembly.
I took the boat out with the family for her ‘maiden’ voyage, with a full tank and we had a blast. Started on the first turn, and WOT came to 5250 when trimmed, with the 14.5 x 17 prop. ( a little nicked but decent 3 blade alum prop). Because everything ran great, I was clear to tear down. The deck was completely destroyed and rotted. It took me about a month to finish on and off. Engine and it’s wiring was not touched.
List of work I completed: Completely stripped to metal, cleaned, New deck, all aux. wiring new, new fuel tank and sender unit, original anti-siphon valve, new lines from tank to bulb, new bulb, new line from bulb to engine (mech installed but looks like a soft auto line..). Console throttle control was removed for tear down and paint, but replaced exactly, at least I’m pretty confident of that. Moeller fuel filter and water separator was installed between the tank and primer bulb.
Had the boat out probably 5 times after all of this in the last 3 weeks and did not notice problems, I certainly did not notice an idle issue like now, it’s hard to get loaded to the trailer without it stalling out now.
Last week, the sparkplugs I’d ordered some time ago finally arrived so I installed them as mech suggested I ‘get around to it sometime’. I noted the gap on the original NGK’s was between 0.40-0.45. I gapped the new Champion Copper Plus Marine Spark Plugs - QL78YC to 0.30 per specs for the engine. While back there, I also pulled then reinstalled the port thermostat to see what is in there so I could order the correct ones as mech suggested I ‘get around to it sometime’. I also swapped the dinged up 14.5 x 17 prop to one of the two brand new spare 15 x 19 props the boat came with.
Took one of my sons to the lake the following day and my condition was suddenly there, as though someone flipped a switch. Cold starts fine, idled in gear out of no wake zone and quits. Not sputters or struggles, just like a slow and quiet shutdown. Idle in neutral sits around 900 RPM. In gear the idle slows to 550-750 and quits. I realized I never primer the bulb before, so I did and it made no difference, the idle speed in gear shutdown continued. Got on plane and ran to a fishing spot, realizing WOT RPM was suddenly only 4300-4500. Start after shutdown for 30 minutes was not good. Would start and quit. Seems like when in ‘quickstart’ it’s fine for those 10 seconds, then idle drops and she quits. Went home. (hour drive). Seems obvious as I write this that its the plugs because that what I changed before this conditions sudden onset, but please read on..
Swapped prop back to 14.5 x 17 and started researching. Hesitated to swap plugs for old ones because you’d think new plugs properly gapped are best.. Went back out to the lake and WOT increased to 4700, otherwise no change in top end, still feels like I’m at ¾ throttle and idle in gear still quit regularly especially after warmed up. Went home. Prepped for seafoam decarb, 1 gallon fresh fuel with 1 can of seafoam hooked at primer bulb. Fake lake in tub. 15 minutes idle, 15 minutes off, several times. After 1 gallon I was still smoking like crazy so I ran another half gallon mix and still crazy smoke. Manually choked each cylinder with a rag thinking maybe something is lodged in needle and if I’m lucky it’ll get pulled. Decided to discontinue because I have 4 kids under 8 and wife needed help… and smoke was slowing.
Next morning went to the lake with one of my sons. I think I gained maybe 100 RPM at WOT, to about 4800-4950 but no more. Still felt like I was at ¾ throttle. Still quits at idle in gear. Fished a bit and went home. Scratched head a lot and worried about fuel delivery or possible power pack issues, temp sensor or timing issues. (Also, I hoped that maybe the new pickup tube in tank was leaking and because I've had a half tank since the condition began I was sucking air, so I fill full before this trip out and it made no difference :/)
Got home, visually checked for fuel leaks or sound of air when priming. No apparent leaks, prime bulb pumps alright to hard, then holds hard for about ten minutes before losing any hardness- engine off. No visible kinks or leaks in fuel lines. Carb air horn area is a tiny bit slick but just barely, evident visually after air silencer is removed - all 6 carbs.
There is a kink in a ?vacuum line that hooks to the base of the air silencer on port side. Looks like it’s always been like that, cut the line ¾ inch and reinstalled, still kinks. See pic. Not sure it matters.
Timing hasn’t been touched, carbs haven’t been touched other than seafoam decarb, no linkages or screws or adjustments have been touched.
Next day I took one of my daughter’s out ‘fishing’.. She’s 3 so it’s a different kind of fishing.. Anyways brought the old plugs (gapped at 0.40-0.45, as opposed to the new ones I gapped at 0.30). Had the same issues, quits at idle in gear especially when warm, and WOT doesn’t break 4900, trimmed gps ground speed won’t break 34mph and feels like I have ¾ throttle. We sat and fished for 30 minutes, I swapped back to the old plugs. Note old and new plugs are equally ‘dirtied’. The new ones are just cleaner, but each one looks the same, a little oiled. There is visible wet oil in the first few threads of each plug. The 0.40-0.45 old plugs made no difference. I gained maybe 50 RPM to 4950 max. In gear idle stall condition is also still there. Went home. IR temp on head 1.25 hours after running was about 115 degrees for each plug, so I think I’m getting spark pnl all?
We’ve arrived at today in this saga.
Note: The boat was purchased at 5000 MSL, and I live at 1800 MSL, but I doubt this matters as I ran fine the first time out here, and I’d doubt previous owners rejetted.. but you never know.
Carburetor choke plates all move together, and visually appear to fully open at full throttle.
The new fuel tank was ‘slightly’ modified to fit.. The original Moeller 38 gallon isn’t made anymore and nothing similar. Originally the filler was on the bow end, as was the vent. The sender was mid way, and the supply pickup valve is at the stern. The new tank had supply and vent locations in reverse, supply next to the filler and the vent at the other end. In order to make it work best, I pulled the press in vent and supply pickup valves and swapped them. (The pickup broke, so I ordered and install a new one). Now the setup mimicks the original, supply pickup tube is at lowest point in stern, and filler and vent are highest on bow end.
When I first ran the boat after getting it back from the mechanic, I had a half tank of who knows how old fuel, so I topped off the remaining 15 or so gallons with fresh 91 and a little marvels mystery oil (can’t hurt I suppose). Ran fine then, and even after the new tank and probably 30 gallons of 87 in the course of 5 or 6 trips it seemed fine before this sudden condition I have now.
The carb float bowls are warped, but have been since I got it. I understand maybe I’m introducing air but I doubt this is the case as I was fine for many trips until the condition came on suddenly, and I’m okay at power bands after idle and before WOT.
I’m really thinking maybe I dropped a cylinder but if that was the case, I’d think it wouldn’t run as well as it does between idle and WOT. I’d think I’d hear a miss or at least hesitation when increasing throttle, and I don’t.
I have a service manual on order, and a new throttle roller on order (Johnson/Evinrude/OMC New OEM ROLLER&SLEEVE AY 0432639, 432639). See pics, the roller was yellow and cracked so I warmed heat shrink tube on it which actually didnt change the diameter at all as it firmed and shrank just enough to make up the difference in added thickness of the shrink tube.
Below are excerpts from a variety of threads I’ve found searching several forums and posts that seem possibly related. I’ve never used a timing light or even tested spark other than holding a plug against the block to see spark.. But I can quickly learn how to use the tools and try to pick up the most basic inexpensive ones.
Can someone point me in the right direction, what to check in what order? I’m thinking spark/timing, but I could easily be wrong. I’m nervous to put a timing light on it at WOT in gear at 34mph on the lake.. Hope I can get this cleared up without pulling the carbs and having to buy rebuild kits. Plan to do that when I have an income again this winter or next year.
Below excerpts from the following threads:
https://forums.iboats.com/forum/eng...oards/115428-2000-johnson-150-sudden-rpm-loss
https://forums.iboats.com/forum/eng...oards/96718-02-150-johnson-wot-losing-500-rpm
https://forums.iboats.com/forum/eng...outboards/427280-79-johnson-150-lost-1000-rpm
https://forums.iboats.com/forum/eng...outboards/511578-not-getting-up-to-full-speed
SPARK/ TIMING/ QuickStart / Other
Get yourself a sparkplug tester at autozone or Discount autoparts and fire it up. Go spark plug cable by sparkplug cable and see if you have spark. You might of dropped a cylinder.
You won't know until you do the testing,but I think you're loosing spark at one or more cylinders.But also be aware,if you had water in the gas,it won't run right until you get fresh gas AND take the carbs apart for cleaning. Water in the carbs will not burn away or dissappear on it's own
Remove the plastic cover on top of the flywheel and you will see the plastic timing wheel (has lots of slots in it) which rotates with the flywheel. Under this is the optical timing sensor (eye) which is mounted on a sliding plate which rotates as the throttle is advanced. This is what advances the ignition timing as the throttle is opened.Check to see that this rotates smoothly as the throttle is opened (don't need to have the motor going - just operate the throttle lever) and importantly that it returns smoothly under spring tension when the throttle is closed. These can stick which will affect the relationship between ignition timing and throttle position.Maybe something esle is sticking/binding there but if you remove the cover you should be able to see the linkages.Your loss of rpms could be caused by incorrect WOT timing but more likely you are dropping cylinders, which as Walker says can be verified with a timing light while running on the lake. The timing wheel has marks on it corresponding to each cylinder so as you connect the timing light to each spark plug lead you will see if that cylinder is getting a spark.Suggest if you haven't already got one that you get a servcie manual as this has all the details in it.
QuikStart (a 10° timing advance) activates as long as the engine RPM is below 1,100, the engine temperature is below 105 F and the yellow/red wire from the starter solenoid is not feeding 12 volts DC to the power pack all of the time. QuikStart also will activate for five to 10 seconds each time the engine is started regardless of engine temperature.
At cranking speed the voltage from the stator may not be enough to operate the circuits inside the power pack, so there is battery voltage supplied from the starter solenoid via the yellow/red striped wire. The extra voltage is needed in order for the optical sensor to operate correctly as low voltage from the battery and/or stator can cause intermittent or no fire at all.
Here's a quick way to check .
Engine running, put a v meter on the yellow/red stripe wire from the starter solenoid to the powerpack, any voltage on that wire guarantees it will stay stuck in QStart.
That's a solenoid short.
If you find no voltage in that wire the fault is in the temp switch or PP.
But before going down that road I would verify the timing hasn't drifted and advanced.
Make sure the throttle pickup roller sleeve is intact, a clear plastic sleeve that fits over the roller , it breaks and drops in the lower cowl.
Verify ignition linkage all move freely and retards to the proper position when throttle is pulled back.
500 to 600 rpms is just about exactly what you lose when you lose spark on one cylinder at that rpm. If you use your timing light you may be able to see which one it is. It may be just a coil. If you take the top cover off you can check the timing too. keep in mind the sometimes a timing light has a funny effect on the optic sensor (eye). Look real close at the encoder wheel to make sure it isnt cracked.
bad coil or power pack? Get a timing light and a buddy. Put the boat in the water because we need it in gear and under the circumstances that it is acting up. Make sure someone knows how a timing light works. When it acts up have him check each plug wire separately for spark. You do nothing with the flywheel and you better not change any timing. We are only checking to see which if any coils are bad. If you find a plug wire or two that have no spark then that is your problem. If you find one that is not sparking change the coil with one that you know is working and see if the problem follows. That is if the cylinder that you swapped coils with that used to work doesn't now then you know the coil is bad and you can replace it. Btw the coil is what the spark plug wire runs into. These things sometimes break down under a load but work fine in neutral or no load conditions.
First make sure your timer plate is advancing all the way to the stop bolt. Then try cleaning all the coil ground straps and the engine block where they bolt on.
An inductive timing light would tell you if you are loosing spark at high RPM
take a spray bottle with fuel mix in it and at this "3/4 won't go any faster point"...spray fuel mix in the carb throats, if it picks up rpms..you have a fuel delivery issue, if the motor bogs..it's getting enough fuel and it's time to check the ignition system...
Check the stator. I bet its bad.
Check idle and WOT timing. But they were never touched between good running to bad so I cannot imagine that’s it..
FUEL/AIR issue:
check for debris in the anti-siphon valve at the fuel tank
Check for debris in carb needles
Make sure butterfly's are all fully closed at idle, it could be as simple as a carb air leak.
With the engine NOT running take any covers off so you can see the carbs. Put it in gear and go to full throttle and watch the butterflies in your carbs. They should all open the same amount as you "give it gas". At wot they should be level. If they are not then you need to do a link and sync so they open at the proper time. If they are okay then you are getting too much air or not enough fuel. Is your tank vent open? Make sure that it gets air in there or you will have the same problem. You can also pump your primer bulb when it does this. If it picks up and goes then you have a weak fuel pump.
SeasportThere are different jets in each carb for idling and high speed. You may not notice high speed performance with restricted low speed jets. A good cleaning and rebuild will never hurt.
Sounds like richening the idle mixture may help. I need to read up on how to adjust the carbs. Is this tricky given that there are six carbs to adjust (I presume)?
Hi Jerry, Welcome to iboats. Well a bit of water has passed under the bridge since this post. A lot of people with these motors (150 & 175 loopers) report similar problems. Seems to be a common problem with these motors. Whether it's related to any one cause is hard to tell. From what I've picked up from others, it's important that the motor is setup correctly, i.e. lync & sync & timing are spot on and that low speed carb jets are set correctly.I've done quite a lot of checking/tuning on my motor but can't actually verfiy if I've fixed the problem completely as it's winter here and I've only used my boat once in the last 3 months. Last time I went out it seemed to be OK but I didn't get a chance to give it a good test.A few things I've picked up:The reason that the problem only occurs when the motor is warm is probably related to the fact that the motor has a Quikstart feature which advances the ignition timing by 10 degrees when it is cold. Seems to make a difference.My motor had a sticky timing plate (a few others have reported the same problem). The optical timing sensor is attached to a rotating plate which rotates in a plastic track. This is returned to idle position under spring tension. Mine wasn't returning fully. I fixed this myself using fine valve grinding paste. I lapped the two surfaces into each other until the plate rotated freely (with some grease to lubricate).So my advice;- Check that timing is spot on (you need an anlayzer to do this properly - I can help with this if you want to build your own.)- Check that idle mixture screws are set not too lean- Check that throttle/ignition are linked & synched correctlyYou'll need a service manual if you want to have a go at these yourself (not too hard).
Sounds like a very similar problem to the one that I (& others) had. My problem is completely fixed. It wasn't a fuel problem. I can't be 100% sure but I think it was related to the timing advance plate sticking and not fully returning as in my post above. This advances your timing at low throttle settings. I'd check this out first. Aso check your link & sync is set up correctly. It's easy to do if you have the manual.
OTHER:
Try taking the cowling of and running it. Exhaust leak would cause issues
I’m at a point where I have researched a lot of things related to this. From timing, to power pack, to fuel starvation and air in fuel. I know I should pull and clean the carbs for good measure and link/sync, but I am hoping someone will read this novel and something will stick out which you’d suggest I start with. I am in the travel industry and business has come to a complete standstill since March 1. I am now trying to very selectively troubleshoot/spend money on parts and tools as times are uncertain. I’d prefer not to just drop new parts left and right if it’s not going to solve the issue.
Please, someone if something in my novel strikes you, please help me out. I greatly appreciate you!
2001 Johnson 150 J150PLSIF sudden condition
Condition: WOT was 5250 with 14.5 x 17 prop, I thought that was correct. Mech says should be between 5000-5500. Idle seemed fine before. Last week like a switch was flipped: WOT dropped from 5250 to 4700, sounds fine just wont increase, just feels like it's at 3/4 throttle setting but it's actually maxed out. Cold start is still perfect, sounds fine, but dies at idle in gear after having been warmed and run. I don’t know the ground speed before the condition began, just the RPM, but with the condition, the groundspeed maxes at 34.2 mph, seems slower than before.
Background: This condition came on suddenly. It’s possible it’s related to some of the changes I’ve made due to the timing of them and the condition appearing, but I really don’t think the changes would cause the sudden condition. Please see below.
I got the boat 2 months ago in FEB 2020 in trade. It’s a 2000 22ft Lowe alum v deck boat. It’s an OIS setup. When I picked it up, it was on a trailer with the cover caved in and 16 inches of solid ice and snow melt on deck like a pool. Previous owner said carbs had been rebuilt in the last six months at a cost of ‘thousands’. I don’t have much to go on whether or not he is honest. Supposedly ran until 6 months ago, then wouldn’t run. My plan was to get her running, then do a complete rebuild of the boat. I brought it to a marine mechanic who found the VRO/fuel pump was shot. Mech. did the following: Reseal steering, flush, fill, bleed. R&R VRO, test,. Drain, flush, test alarm, install new oil, purge line oil tank. R&R Waterpump kit and gear lube, clean port temp sender for quickstart, new primer bulb, 2 case plug gaskets, repair trim leakdown issue. Compression came back: 1-121, 2-117, 3-120, 4-125, 5-115, 6-117. Total bill was $1850.. He suggested the following maintenance ‘when you get around to it’: sparkplugs QL78YC @0.30, H20 separator kit, throttle roller, prop, t-stat kits, fuel filter assembly.
I took the boat out with the family for her ‘maiden’ voyage, with a full tank and we had a blast. Started on the first turn, and WOT came to 5250 when trimmed, with the 14.5 x 17 prop. ( a little nicked but decent 3 blade alum prop). Because everything ran great, I was clear to tear down. The deck was completely destroyed and rotted. It took me about a month to finish on and off. Engine and it’s wiring was not touched.
List of work I completed: Completely stripped to metal, cleaned, New deck, all aux. wiring new, new fuel tank and sender unit, original anti-siphon valve, new lines from tank to bulb, new bulb, new line from bulb to engine (mech installed but looks like a soft auto line..). Console throttle control was removed for tear down and paint, but replaced exactly, at least I’m pretty confident of that. Moeller fuel filter and water separator was installed between the tank and primer bulb.
Had the boat out probably 5 times after all of this in the last 3 weeks and did not notice problems, I certainly did not notice an idle issue like now, it’s hard to get loaded to the trailer without it stalling out now.
Last week, the sparkplugs I’d ordered some time ago finally arrived so I installed them as mech suggested I ‘get around to it sometime’. I noted the gap on the original NGK’s was between 0.40-0.45. I gapped the new Champion Copper Plus Marine Spark Plugs - QL78YC to 0.30 per specs for the engine. While back there, I also pulled then reinstalled the port thermostat to see what is in there so I could order the correct ones as mech suggested I ‘get around to it sometime’. I also swapped the dinged up 14.5 x 17 prop to one of the two brand new spare 15 x 19 props the boat came with.
Took one of my sons to the lake the following day and my condition was suddenly there, as though someone flipped a switch. Cold starts fine, idled in gear out of no wake zone and quits. Not sputters or struggles, just like a slow and quiet shutdown. Idle in neutral sits around 900 RPM. In gear the idle slows to 550-750 and quits. I realized I never primer the bulb before, so I did and it made no difference, the idle speed in gear shutdown continued. Got on plane and ran to a fishing spot, realizing WOT RPM was suddenly only 4300-4500. Start after shutdown for 30 minutes was not good. Would start and quit. Seems like when in ‘quickstart’ it’s fine for those 10 seconds, then idle drops and she quits. Went home. (hour drive). Seems obvious as I write this that its the plugs because that what I changed before this conditions sudden onset, but please read on..
Swapped prop back to 14.5 x 17 and started researching. Hesitated to swap plugs for old ones because you’d think new plugs properly gapped are best.. Went back out to the lake and WOT increased to 4700, otherwise no change in top end, still feels like I’m at ¾ throttle and idle in gear still quit regularly especially after warmed up. Went home. Prepped for seafoam decarb, 1 gallon fresh fuel with 1 can of seafoam hooked at primer bulb. Fake lake in tub. 15 minutes idle, 15 minutes off, several times. After 1 gallon I was still smoking like crazy so I ran another half gallon mix and still crazy smoke. Manually choked each cylinder with a rag thinking maybe something is lodged in needle and if I’m lucky it’ll get pulled. Decided to discontinue because I have 4 kids under 8 and wife needed help… and smoke was slowing.
Next morning went to the lake with one of my sons. I think I gained maybe 100 RPM at WOT, to about 4800-4950 but no more. Still felt like I was at ¾ throttle. Still quits at idle in gear. Fished a bit and went home. Scratched head a lot and worried about fuel delivery or possible power pack issues, temp sensor or timing issues. (Also, I hoped that maybe the new pickup tube in tank was leaking and because I've had a half tank since the condition began I was sucking air, so I fill full before this trip out and it made no difference :/)
Got home, visually checked for fuel leaks or sound of air when priming. No apparent leaks, prime bulb pumps alright to hard, then holds hard for about ten minutes before losing any hardness- engine off. No visible kinks or leaks in fuel lines. Carb air horn area is a tiny bit slick but just barely, evident visually after air silencer is removed - all 6 carbs.
There is a kink in a ?vacuum line that hooks to the base of the air silencer on port side. Looks like it’s always been like that, cut the line ¾ inch and reinstalled, still kinks. See pic. Not sure it matters.
Timing hasn’t been touched, carbs haven’t been touched other than seafoam decarb, no linkages or screws or adjustments have been touched.
Next day I took one of my daughter’s out ‘fishing’.. She’s 3 so it’s a different kind of fishing.. Anyways brought the old plugs (gapped at 0.40-0.45, as opposed to the new ones I gapped at 0.30). Had the same issues, quits at idle in gear especially when warm, and WOT doesn’t break 4900, trimmed gps ground speed won’t break 34mph and feels like I have ¾ throttle. We sat and fished for 30 minutes, I swapped back to the old plugs. Note old and new plugs are equally ‘dirtied’. The new ones are just cleaner, but each one looks the same, a little oiled. There is visible wet oil in the first few threads of each plug. The 0.40-0.45 old plugs made no difference. I gained maybe 50 RPM to 4950 max. In gear idle stall condition is also still there. Went home. IR temp on head 1.25 hours after running was about 115 degrees for each plug, so I think I’m getting spark pnl all?
We’ve arrived at today in this saga.
Note: The boat was purchased at 5000 MSL, and I live at 1800 MSL, but I doubt this matters as I ran fine the first time out here, and I’d doubt previous owners rejetted.. but you never know.
Carburetor choke plates all move together, and visually appear to fully open at full throttle.
The new fuel tank was ‘slightly’ modified to fit.. The original Moeller 38 gallon isn’t made anymore and nothing similar. Originally the filler was on the bow end, as was the vent. The sender was mid way, and the supply pickup valve is at the stern. The new tank had supply and vent locations in reverse, supply next to the filler and the vent at the other end. In order to make it work best, I pulled the press in vent and supply pickup valves and swapped them. (The pickup broke, so I ordered and install a new one). Now the setup mimicks the original, supply pickup tube is at lowest point in stern, and filler and vent are highest on bow end.
When I first ran the boat after getting it back from the mechanic, I had a half tank of who knows how old fuel, so I topped off the remaining 15 or so gallons with fresh 91 and a little marvels mystery oil (can’t hurt I suppose). Ran fine then, and even after the new tank and probably 30 gallons of 87 in the course of 5 or 6 trips it seemed fine before this sudden condition I have now.
The carb float bowls are warped, but have been since I got it. I understand maybe I’m introducing air but I doubt this is the case as I was fine for many trips until the condition came on suddenly, and I’m okay at power bands after idle and before WOT.
I’m really thinking maybe I dropped a cylinder but if that was the case, I’d think it wouldn’t run as well as it does between idle and WOT. I’d think I’d hear a miss or at least hesitation when increasing throttle, and I don’t.
I have a service manual on order, and a new throttle roller on order (Johnson/Evinrude/OMC New OEM ROLLER&SLEEVE AY 0432639, 432639). See pics, the roller was yellow and cracked so I warmed heat shrink tube on it which actually didnt change the diameter at all as it firmed and shrank just enough to make up the difference in added thickness of the shrink tube.
Below are excerpts from a variety of threads I’ve found searching several forums and posts that seem possibly related. I’ve never used a timing light or even tested spark other than holding a plug against the block to see spark.. But I can quickly learn how to use the tools and try to pick up the most basic inexpensive ones.
Can someone point me in the right direction, what to check in what order? I’m thinking spark/timing, but I could easily be wrong. I’m nervous to put a timing light on it at WOT in gear at 34mph on the lake.. Hope I can get this cleared up without pulling the carbs and having to buy rebuild kits. Plan to do that when I have an income again this winter or next year.
Below excerpts from the following threads:
https://forums.iboats.com/forum/eng...oards/115428-2000-johnson-150-sudden-rpm-loss
https://forums.iboats.com/forum/eng...oards/96718-02-150-johnson-wot-losing-500-rpm
https://forums.iboats.com/forum/eng...outboards/427280-79-johnson-150-lost-1000-rpm
https://forums.iboats.com/forum/eng...outboards/511578-not-getting-up-to-full-speed
SPARK/ TIMING/ QuickStart / Other
Get yourself a sparkplug tester at autozone or Discount autoparts and fire it up. Go spark plug cable by sparkplug cable and see if you have spark. You might of dropped a cylinder.
You won't know until you do the testing,but I think you're loosing spark at one or more cylinders.But also be aware,if you had water in the gas,it won't run right until you get fresh gas AND take the carbs apart for cleaning. Water in the carbs will not burn away or dissappear on it's own
Remove the plastic cover on top of the flywheel and you will see the plastic timing wheel (has lots of slots in it) which rotates with the flywheel. Under this is the optical timing sensor (eye) which is mounted on a sliding plate which rotates as the throttle is advanced. This is what advances the ignition timing as the throttle is opened.Check to see that this rotates smoothly as the throttle is opened (don't need to have the motor going - just operate the throttle lever) and importantly that it returns smoothly under spring tension when the throttle is closed. These can stick which will affect the relationship between ignition timing and throttle position.Maybe something esle is sticking/binding there but if you remove the cover you should be able to see the linkages.Your loss of rpms could be caused by incorrect WOT timing but more likely you are dropping cylinders, which as Walker says can be verified with a timing light while running on the lake. The timing wheel has marks on it corresponding to each cylinder so as you connect the timing light to each spark plug lead you will see if that cylinder is getting a spark.Suggest if you haven't already got one that you get a servcie manual as this has all the details in it.
QuikStart (a 10° timing advance) activates as long as the engine RPM is below 1,100, the engine temperature is below 105 F and the yellow/red wire from the starter solenoid is not feeding 12 volts DC to the power pack all of the time. QuikStart also will activate for five to 10 seconds each time the engine is started regardless of engine temperature.
At cranking speed the voltage from the stator may not be enough to operate the circuits inside the power pack, so there is battery voltage supplied from the starter solenoid via the yellow/red striped wire. The extra voltage is needed in order for the optical sensor to operate correctly as low voltage from the battery and/or stator can cause intermittent or no fire at all.
Here's a quick way to check .
Engine running, put a v meter on the yellow/red stripe wire from the starter solenoid to the powerpack, any voltage on that wire guarantees it will stay stuck in QStart.
That's a solenoid short.
If you find no voltage in that wire the fault is in the temp switch or PP.
But before going down that road I would verify the timing hasn't drifted and advanced.
Make sure the throttle pickup roller sleeve is intact, a clear plastic sleeve that fits over the roller , it breaks and drops in the lower cowl.
Verify ignition linkage all move freely and retards to the proper position when throttle is pulled back.
500 to 600 rpms is just about exactly what you lose when you lose spark on one cylinder at that rpm. If you use your timing light you may be able to see which one it is. It may be just a coil. If you take the top cover off you can check the timing too. keep in mind the sometimes a timing light has a funny effect on the optic sensor (eye). Look real close at the encoder wheel to make sure it isnt cracked.
bad coil or power pack? Get a timing light and a buddy. Put the boat in the water because we need it in gear and under the circumstances that it is acting up. Make sure someone knows how a timing light works. When it acts up have him check each plug wire separately for spark. You do nothing with the flywheel and you better not change any timing. We are only checking to see which if any coils are bad. If you find a plug wire or two that have no spark then that is your problem. If you find one that is not sparking change the coil with one that you know is working and see if the problem follows. That is if the cylinder that you swapped coils with that used to work doesn't now then you know the coil is bad and you can replace it. Btw the coil is what the spark plug wire runs into. These things sometimes break down under a load but work fine in neutral or no load conditions.
First make sure your timer plate is advancing all the way to the stop bolt. Then try cleaning all the coil ground straps and the engine block where they bolt on.
An inductive timing light would tell you if you are loosing spark at high RPM
take a spray bottle with fuel mix in it and at this "3/4 won't go any faster point"...spray fuel mix in the carb throats, if it picks up rpms..you have a fuel delivery issue, if the motor bogs..it's getting enough fuel and it's time to check the ignition system...
Check the stator. I bet its bad.
Check idle and WOT timing. But they were never touched between good running to bad so I cannot imagine that’s it..
FUEL/AIR issue:
check for debris in the anti-siphon valve at the fuel tank
Check for debris in carb needles
Make sure butterfly's are all fully closed at idle, it could be as simple as a carb air leak.
With the engine NOT running take any covers off so you can see the carbs. Put it in gear and go to full throttle and watch the butterflies in your carbs. They should all open the same amount as you "give it gas". At wot they should be level. If they are not then you need to do a link and sync so they open at the proper time. If they are okay then you are getting too much air or not enough fuel. Is your tank vent open? Make sure that it gets air in there or you will have the same problem. You can also pump your primer bulb when it does this. If it picks up and goes then you have a weak fuel pump.
SeasportThere are different jets in each carb for idling and high speed. You may not notice high speed performance with restricted low speed jets. A good cleaning and rebuild will never hurt.
Sounds like richening the idle mixture may help. I need to read up on how to adjust the carbs. Is this tricky given that there are six carbs to adjust (I presume)?
Hi Jerry, Welcome to iboats. Well a bit of water has passed under the bridge since this post. A lot of people with these motors (150 & 175 loopers) report similar problems. Seems to be a common problem with these motors. Whether it's related to any one cause is hard to tell. From what I've picked up from others, it's important that the motor is setup correctly, i.e. lync & sync & timing are spot on and that low speed carb jets are set correctly.I've done quite a lot of checking/tuning on my motor but can't actually verfiy if I've fixed the problem completely as it's winter here and I've only used my boat once in the last 3 months. Last time I went out it seemed to be OK but I didn't get a chance to give it a good test.A few things I've picked up:The reason that the problem only occurs when the motor is warm is probably related to the fact that the motor has a Quikstart feature which advances the ignition timing by 10 degrees when it is cold. Seems to make a difference.My motor had a sticky timing plate (a few others have reported the same problem). The optical timing sensor is attached to a rotating plate which rotates in a plastic track. This is returned to idle position under spring tension. Mine wasn't returning fully. I fixed this myself using fine valve grinding paste. I lapped the two surfaces into each other until the plate rotated freely (with some grease to lubricate).So my advice;- Check that timing is spot on (you need an anlayzer to do this properly - I can help with this if you want to build your own.)- Check that idle mixture screws are set not too lean- Check that throttle/ignition are linked & synched correctlyYou'll need a service manual if you want to have a go at these yourself (not too hard).
Sounds like a very similar problem to the one that I (& others) had. My problem is completely fixed. It wasn't a fuel problem. I can't be 100% sure but I think it was related to the timing advance plate sticking and not fully returning as in my post above. This advances your timing at low throttle settings. I'd check this out first. Aso check your link & sync is set up correctly. It's easy to do if you have the manual.
OTHER:
Try taking the cowling of and running it. Exhaust leak would cause issues
