Carburetor question on restoration I’m working on 1992 40 hp MSHQ Yamaha

[Faztbullet]

Well a engine can run lean at WOT if fuel pressure is low, float level set to high and fuel/oil mix if premix is to rich of oil....

 

[Sea Rider]

Faz was only giving reasons for clean plugs

but then people play with jetting all the time changing things and some jets/passages can get partially restricted.
someone saying the carbs are clean does not always mean that is true

Was just asking how can clean carbs run at wot with lean conditions. Those 3 carbs have been well cleaned to perfection and right after that the yammie should have gone straight through a long CRC decarbon process. Sorry I only perform a one time full carb clean out and if run the carb's bowl dry that carb won't be seeing me in years to come...

Happy Boating​

 

[Douglasdzaster]

Hello gentlemen, actually it’s seen more idle time than wot lake time ,seems I’m always finding something wrong. Maybe I just need to run it. I did go back through the carburetors. All was clean and all jets were open. I had crushed all three of the seat o rings when I rebuilt. I’ve installed new o rings properly this time. Here are a couple of pictures of the plugs today. Please compare to post number 31 and give an opinion if they look cleaner today or not. Plugs don’t have a lot of time on them. When I pulled them today they were wet, I figure from idling on muffs the other day. But didn’t smell like gas. Pilots are all around 1 1/2 turns out. I’m running 50:1 mix with Lucas synthetic blend. The motor smokes little to none. I’d figure an old 2 stroke would smoke more. It actually smoked more when I first got it. I have run a can of Seafoam in a 6 gallon tank but haven’t actually decarbed. I have a can of CRC ready to go. I’m hoping I’m worrying about nothing and y’all tell me the plugs are fine and to run it. Thanks again I’m very grateful for the insight and sharing your knowledge.

 

[Faztbullet]

Plugs are fine..the Lucas has a detergent in it makes it run cleaner and will actually decarbon some. Just quit looking and go fishing.

 

[Douglasdzaster]

Hello gentlemen, actually it’s seen more idle time than wot lake time ,seems I’m always finding something wrong. Maybe I just need to run it. I did go back through the carburetors. All was clean and all jets were open. I had crushed all three of the seat o rings when I rebuilt. I’ve installed new o rings properly this time. Here are a couple of pictures of the plugs today. Please compare to post number 31 and give an opinion if they look cleaner today or not. Plugs don’t have a lot of time on them. When I pulled them today they were wet, I figure from idling on muffs the other day. But didn’t smell like gas. Pilots are all around 1 1/2 turns out. I’m running 50:1 mix with Lucas synthetic blend. The motor smokes little to none. I’d figure an old 2 stroke would smoke more. It actually smoked more when I first got it. I have run a can of Seafoam in a 6 gallon tank but haven’t actually decarbed. I have a can of CRC ready to go. I’m hoping I’m worrying about nothing and y’all tell me the plugs are fine and to run it. Thanks again I’m very grateful for the insight and sharing your knowledge.

 

[Douglasdzaster]

Plugs are fine..the Lucas has a detergent in it makes it run cleaner and will actually decarbon some. Just quit looking and go fishing.

Thank you sir! I’ll decarbed and then run it like I stole it. Then back to scouting out the fishing on this lake. I’m trying to find me some catfish and crappie spots but I keep stopping to catch more bass. LoL

 

[Faztbullet]

Take ya 3 pallets ,stand on edge and make a triangle. Put 2 concrete blocks on bottom and chuck it over the side in 6-15 ft of water near a ditch or creek bend. Bait it up with several cans of cheap dog food and da crappie will come. Have several dozen set out.

 

[Sea Rider]

Running a can of Seafoam in a motor which has collected huge carbon buildups through the years which has never been properly decarboned won't even tickle the motor....

Happy Boating​

 

[Sea Rider]

Need to perform the CRC decarbon procedure, I'm sure that motor has tons of carbon builups on the piston rings, exhaust and combustion chambers, will idle much better after a long wot run an if stealing the combo for say 10-15 minutes.

Happy Boating​

This is a live proof that CRC marine decarbonizer does its homework very well. First pic corresponds to a 2 stroke crankcase which has never been decarboned ever before. ​

Second pic corresponds to a second motor which has been religiously decarboned with CRC decarbonizer at each 50 run hours, both motors with around 200 run hours from new...

Happy Boating​

 

[FishMan001]

This is a live proof that CRC marine decarbonizer does its homework very well. First pic corresponds to a 2 stroke crankcase which has never been decarboned ever before. ​

View attachment 346457

Second pic corresponds to a second motor which has been religiously decarboned with CRC decarbonizer at each 50 run hours, both motors with around 200 run hours from new...

Happy Boating​

IF, these two engines have done the same hours, then they have obviously not been used in the same environment, or in the same way, so is not a good comparison. No decarbonizer on the market can make the water channels clean. Also, the mating/gasket surfaces are very different.
Finally, I don't know if you are a promoter, but, CRC decarbonizer is basically a USA product, and it almost prohibitively expensive anywhere else in the world due to postage, customs, import duties etc.

JMTP.
Regards.

 

[Sea Rider]

IF, these two engines have done the same hours, then they have obviously not been used in the same environment, or in the same way, so is not a good comparison. No decarbonizer on the market can make the water channels clean. Also, the mating/gasket surfaces are very different.
Finally, I don't know if you are a promoter, but, CRC decarbonizer is basically a USA product, and it almost prohibitively expensive anywhere else in the world due to postage, customs, import duties etc.

JMTP.
Regards.

Left one was used as a dinghy tender at low to mid range rpm, the right one was constantly run at at open water running middle to max wot rpm range, although the water passages and mating surfaces has been cleaned the exhaust ports have not.

You guys love and swear by Seafoam that needs to be mixed with fuel inside a tank and will run diluted through a carb into the combustion chamber whereas the CRC decarbonizer runs straight pure through the carb's throat straight into the combustion chamber. It's a much more faster and effective way to decarbon internally any 2 stroke motor.

If you order directly for yourself could end being costly, now a days due to being highly flammable can't be ordered by air freight, the Merc's local dealer imports many items by sea freight, not an issue buying from him at a very reasonable price. In reality I'm promoting a nice product no one wants to try....

Happy Boating
​

 

[Douglasdzaster]

Running a can of Seafoam in a motor which has collected huge carbon buildups through the years which has never been properly decarboned won't even tickle the motor....

Happy Boating​

I did it today. I went into a cove and used the CRC. About half of the can. It coughed spit and tried to die and SMOKED ! Then I drove it like I stole it for quite awhile. Stopped and fished and it started right back up. After warming it back up idling a few minutes I hit wot and the boat jumped out of the hole On plan. Definitely runs smoother and it feels like more power when I’m on the throttle. It’s running better at cruising speeds too while I’m looking for creek channels etc. Still a little rough idling though.
Do I need to wait a while before using the rest of the can or can I do it next time out? This is probably the first decarb the old engine has had. Thanks for suggesting CRC. I’m glad I ordered it.

 

[Sea Rider]

Was the CRC squirted through the carb's air silencer side or you previously drilled 3 small orifices at the upper air silencer with said orifices pointing at the center of each carb's throat ? If the orifices were drilled as suggested at idle/neutral press the can's valve for 1-2 seconds at each orifice, the motor should idle slightly unevenly, let the motor burn the produc to fully recuperate the idling, repeat same step for second/third cylinders.

Can squirt all you want in that order, when finished applying and the smoke has nearly disappeared don't let the motor idle for too long, instead go for a long wot run as if the water patrol is chasing you to burn out all CRC residues, the motor should run much better along achieving a smoother idling than before.


If there's half CRC can left, repeat the whole process in a few days, would be desirable before going that route to remove all spark plugs and with a hard bristle toothbrush dampened in laquer thinner brush each plug to clean any carbon already built up on the tip.

Happy Boating​

 

[Douglasdzaster]

Was the CRC squirted through the carb's air silencer side or you previously drilled 3 small orifices at the upper air silencer with said orifices pointing at the center of each carb's throat ? If the orifices were drilled as suggested at idle/neutral press the can's valve for 1-2 seconds at each orifice, the motor should idle slightly unevenly, let the motor burn the produc to fully recuperate the idling, repeat same step for second/third cylinders.

Can squirt all you want in that order, when finished applying and the smoke has nearly disappeared don't let the motor idle for too long, instead go for a long wot run as if the water patrol is chasing you to burn out all CRC residues, the motor should run much better along achieving a smoother idling than before.


If there's half CRC can left, repeat the whole process in a few days, would be desirable before going that route to remove all spark plugs and with a hard bristle toothbrush dampened in laquer thinner brush each plug to clean any carbon already built up on the tip.

Happy Boating​

I drill the holes a while back as instructed. As soon as the idle would come back I did not wait on smoke to clear and sprayed the next carburetor. It would sputter and I’d give it a little gas for a second to keep it running. It actually died once but started right up with one pull. After half a can I put the cowling back on right away and ran wot for about 15 to 20 minutes back and forth around the lake. Then stopped and fished about an hour and it started easier and I ran another 20 minutes or so. It hit wot and put the boat on plan quicker. Also did better cruising different speeds. Felt like I had more power because of better response to the throttle. It idles better but still just a little rough causing the engine to vibrate a little. At low rpms (600 or so) it’s smooth as can be. Still don’t know how accurate the tachometer is. Seems like it’s close at idle by listening and it goes into gear smooth. At wot it may be reading around half. It shows 2,500 to 2,700. The other prop is a size bigger in diameter and one pitch smaller. It pushes the boat a lot better but will show up to 3,000 rpms at wot. And goes around 5 more mph. At different rpms. Warning light doesn’t show anything to indicate over rev. And it doesn’t sound like I’m pushing it. I’ve gotten good through the years just by listening to other small engines but I’m not sure about an outboard. So I back off a little when running the other prop at wot . I’ve got to find an accurate way to measure rpms . This is the third tachometer. It’s on the settings that calls for 2 stroke 3 cylinder. I wonder since it seems to work on idle if I’m not running to slow at wot. I don’t know how fast a 40 hp. Should push a 16/52 flat bottom with just me and a little tackle, one battery, and 6 gallon fuel tank. According to my phone’s gps I’m going 30mph. Talking to other Jon boat owners there running that with 20 and 25hp motors. I’m going to start finally start hitting the river soon since I found someone to guide me through it’s hazards. Some areas I will need wot to get through.

 

[Sea Rider]

Never have decarboned a 3 cylinder motor to tell if the cylinder been squired with CRC will make the motor to rev bit erratically. On 2 stroke 2 cylinder motors need to wait a bit for the dense smoke to clear up before going for the second squirt or motor will die when at idle/neutral. Usually decarbon mines on muffs geared forward to 2-2.5 K constant revs which allows more CRC intake without dying.

The tach used surely it's reading half of what should be, have you tried the Hardline hour/tach model : HR-8062-2 ? I guess that's very difficult to perfectly fine tune spot on all 3 carbs with same number of in-out idle screw turns. Do you remenber one of your carbs has a larger installed jet as the required one was not available when ordered, I don't know what effect it might have on the engine's idling balance ? Now with decarboned piston rings make a cylinder compression test to check if compression is even or close between cylinders, will indicate how healthy the motor is.

With respect to other boaters running 2 stroke 20-25 HP motors and achieveing similar 30 HP wot runs as your combo will be a matter to ask them which were their wot rpm numbers, surely no one has installed induction tachs. If going up current constantly better stay with the second prop, faster up current is better specially if more loaded.

Happy Boating​

 

[Douglasdzaster]

Never have decarboned a 3 cylinder motor to tell if the cylinder been squired with CRC will make the motor to rev bit erratically. On 2 stroke 2 cylinder motors need to wait a bit for the dense smoke to clear up before going for the second squirt or motor will die when at idle/neutral. Usually decarbon mines on muffs geared forward to 2-2.5 K constant revs which allows more CRC intake without dying.

The tach used surely it's reading half of what should be, have you tried the Hardline hour/tach model : HR-8062-2 ? I guess that's very difficult to perfectly fine tune spot on all 3 carbs with same number of in-out idle screw turns. Do you remenber one of your carbs has a larger installed jet as the required one was not available when ordered, I don't know what effect it might have on the engine's idling balance ? Now with decarboned piston rings make a cylinder compression test to check if compression is even or close between cylinders, will indicate how healthy the motor is.

With respect to other boaters running 2 stroke 20-25 HP motors and achieveing similar 30 HP wot runs as your combo will be a matter to ask them which were their wot rpm numbers, surely no one has installed induction tachs. If going up current constantly better stay with the second prop, faster up current is better specially if more loaded.

Happy Boating​

What I’m wondering is how it is correct at idle then only reading half at wot and at what point? I haven’t tried the Hardline. Is it more consistent? I was hoping it wasn’t reading quite half. I like running the new prop at wot.
I wasn’t planning on running the good prop in the river. It won’t hurt near as bad if the older one catches a rock.
When the machinist removed that old jet he didn’t ruin it so I polished it clean and saved it. Not long ago (when I took the grandsons out) it first cut out at wot and I didn’t know what the problem was (water pump) I removed the carburetors again and opened them up. Everything was still spotless but I cleaned everything anyway and put the old jet back in while I was at it. Only took a day this time. Lol most of that was soaking. It was Idling worse until I did that. Glad I saved it.
It just now occurred to me I set the pilot screws right back where they were and haven’t tried adjusting the second carburetor with the original jet now installed. Duh!! I starting doing all my adjustments on the water. Idle seems to fluctuate a little on muffs for some reason.

 

[Faztbullet]

Back it in to water but leave on trailer, start and put in gear, slowly turn in the bottom pilot needle till engine leans spits , then back out till engine smooths out and add 1/8 turn. repeat for each cylinder. Multi carb engines need to be adjusted a tad different than single carb motors.

 

[Sea Rider]

With 600 tached idle revs it's a clear indication that tach is way off, no wonder why reads just 3000 rpm which it's half of the max wot rpm range. If the tach is adjusted to 3 cylinder 2 spark per revolution, check if can be adjusted to 3 cylinder, 1 spark per revolution and if the display reads around 1000 rpm at idle, bingo!!

Inducion tachs are nervous intruments that usually fluctuate their idle readings as much as 100 rpm. When the motor passes idle and it's maintained running throttled at any fix position will achieves steady readings. For your peace of mind and with all 3 carbs adjusted as suggested that motor should be heard revving sweet at idle ?

Happy Boating​