90 Johnson GT150 - Slowly dies from WOT

[tobolamr]

Howdy!

I bought a used boat this past april - our first boat of our own. It's a ProCraft 1950V, 1987 model. The boat has a 1990 Johnson Tracker GT150 on the back, with the VRO style injection system removed... and I've had some issues with it. First time I had it out, the thing ran and then died like we turned off the key - and I learned it "jumped the timing." Dealer replaced the flywheel free of charge & it fired up again.

After I got it back, the thing would spit and sputter at idle and miss at WOT; almost felt like a slipping gear on an old lawn tractor. I had the tank drained, mixed up Premium fuel with the oil and added a can of Sea Foam to 12 gallons, and it's running MUCH better. But, when I had it out the first time after the drain/refill, it would run for about 300-500 yards at WOT and then start to lose power and slowly die off. The fuel bulb was sucked down flat. After 2-3 minutes, I was able to get the bulb firmed up and we could do it again. This was a LOT of fun at the tournament... Glad it was a small lake...

Have since replaced the fuel line & bulb with new. Idle & overall running has improved drastically, but still wants to die at idle. Probably just need to crank up the idle speed a couple hundred RPM... Also, when you're going WOT for several hundred yards, all of a sudden the motor acts like you're pulling off the throttle and surges a little, then it starts slowing down and dies. Takes 10-15 seconds to slow down and die, maybe a few less. Bulb is still fairly firm. I pump the bulb back up, and you can fire up again immediately and do it again.

I've had several suggestions from the "local" wizards. One is that I've got fuel supply problems. Not sure if I buy this - there seems to be plenty of fuel now, and the problem isn't consistent. Plugged vent line? Maybe, but I ran a wire down it and it seems fine. Local guys are thinking "fuel." Called the marina, talked to a tech, they said "You're dropping a cylinder, leaning out or flooding out."

Fuel problem? Carb problem? Pump problem? Losing a cylinder? Motor just notoriously cold blooded? Owner having an ID 10 T error moment? I dunno... Would appreciate any input on what to check. I'm almost ready to take it to the marina (but would rather not see that bill). Thank you!

 

[jonesg]

Re: 90 Johnson GT150 - Slowly dies from WOT

boats are nothing like cars, I wouldn't dream of buying a car and redoing all the fuel delivery components from the pickup to the engine but its good practice to go through everything in a used boat.
Do you have a water seperator?

You need to get a timing light and take it out on the water with the engine cowl removed, try it on different plug wires as the engine acts up and see if it is actually dropping a cylinder.

If not, then its prolly fuel delivery.

After checking or ignition problems with the light try pumping the uel bulb as its starts to die, if the engine picks up again its fuel.
I would pull the pickup from the tank and check its clear, remove the antisyphon valve at the top of the pickup (its in the elbow).


Sounds more like fuel than ignition but you never know til you know.

 

[tobolamr]

Re: 90 Johnson GT150 - Slowly dies from WOT

I also regret to inform you that I forgot one other piece of information...

Before the timing jumped first time around, I noticed that just beforehand, the tach started to jump all over the place - but with no change in the sound of the outboard.

When I had it out on Monday night, the tach would go to WOT RPM's, then drop down to about 3500 and sit there, occasionally jumping back to WOT on the tach.

I do now own a water separating fuel filter. I'm hoping to mount it tomorrow night after work. They drained the tank almost dry for me, but I've got to get the filter installed to know for sure.

I will check the last bits on fuel delivery. This is my first "permanent" tank boat, so I'm learning every step of the way. I'm hoping that the fuel stem is easy to get into. I'm also going to re-check the vent line.

Thank you!

 

[jonesg]

Re: 90 Johnson GT150 - Slowly dies from WOT

"jumped the timing" must be a term for "flywheel magnets came loose."

you need to put a voltmeter across the battery when its running to see if its charging, sounds like the rectifier/regulator is going south, check , clean and tighten all wire connections from the batter, no freakin wing nuts anywhere.

I think you will find the voltage is all over the place, either overcharging or not charging at all. Loose connections can kill electronic components in outboards real easy, so watch yer polarity.!

tach gets its signal from the rectifier, so its a suspect now.
Bring it in for questioning.

 

[crxess]

Re: 90 Johnson GT150 - Slowly dies from WOT

Why are people not reading first?

Fuel bulb sucks flat!

Start there then move on as needed.

You need to check the fuel pick up, in tank first.
Next confirm good venting.

Something is stopping fuel flow. Test motor with a portable tank for a quick confirmation.

 

[jonesg]

Re: 90 Johnson GT150 - Slowly dies from WOT

"why are people not reading"

good quesion,

"Have since replaced the fuel line & bulb with new."

doh!

 

[tobolamr]

Re: 90 Johnson GT150 - Slowly dies from WOT

No biggie - I'm practically famous for reading and not retaining things that are directly in front of me. I'll check the voltage at the battery over the weekend, too. Otherwise, I just found out that a local marina is doing "free outboard check-ups" and I'll drop the boat off on Monday.

 

[crxess]

Re: 90 Johnson GT150 - Slowly dies from WOT

"why are people not reading"

good quesion,

"Have since replaced the fuel line & bulb with new."

doh!

LOL -

Yes, I saw that. should have been more specific. Sounds like your Pickup(inside Tank) is blocked or line inside is collapsed. System not pulling fuel from tank as needed.

That is why I suggested testing with a different tank.

Could be a charging issue, but .........Does it fire back up easily or do you need to let it sit for a considerable time allowing the battery to self charge a bit?

Same with electronic ignition parts. If Heat failure, they should need time to cool before re-firing....failing.....

Free check-up is a great bonus. Never pass up on Free!!

Hope it turns out to be something simple.

Happy Boating

 

[jonesg]

Re: 90 Johnson GT150 - Slowly dies from WOT

Hope it turns out to be something simple.

Happy Boating

It always is, but finding the simple thing is the work.

"its just these simple things ....melting"

uh they LOOk like pistons!

 

[tobolamr]

Re: 90 Johnson GT150 - Slowly dies from WOT

Any suggestions on how to best rig a temporary test fuel tank? I haven't had time to break away from work enough to look at the fuel feed on the tank to see how to take it off yet.

As for electronics...

Whenever the outboard dies now, it can be re-started immediately. I don't even have to pump the bulb, but I do anyways.

Just before the timing got hosed, the tach suddenly started jumping all over the place and would not sit still. Since that repair, the tach had been good... Until monday night.

On monday, when you would go to WOT, it would go to 6200 (I need to reprop) and then it would drop down to like 3500. When slowing down, it would suddenly pick back up to the proper rpm's after you got under about 5200.

Doing my best to be complete without rambling... Thanks!

 

[Jayboid]

Re: 90 Johnson GT150 - Slowly dies from WOT

Any suggestions on how to best rig a temporary test fuel tank? I haven't had time to break away from work enough to look at the fuel feed on the tank to see how to take it off yet.

If you are careful you can just use a 5-gallon jug of premix. Disconnect the fuel hose at any convenient place that still lets you use your primer bulb. Stick the end into the gas and try it out. You will need a helper to make sure the hose stays in the gas can and that the can doesn't tip over. Run the boat. If you no longer have your problem, you have a fuel restriction somewhere prior to where you've disconnected. If it didn't help, have your helper safely elevate your gas can to a position higher than your outboard motor. If that helps, your fuel pump is suspect. If neither of these help and your primer bulb never goes flat any more, fuel restriction would not seem to be your problem.

 

[geedubcpa]

Re: 90 Johnson GT150 - Slowly dies from WOT

I tested my fuel pickup by simply inserting the gas line directly into the gas tank (I know this is hillbilly but it proved my pickup was ok) If it works ok by dropping the fuelline directly in the tank then you can assume the pickup might be clogged or whatever.

Are you fuel connections tight at the motor and the gas tank - if they are loose this can cause the suction to get lost.

 

[tobolamr]

Re: 90 Johnson GT150 - Slowly dies from WOT

Thank you, everyone.

I tested the fuel system over the weekend, with the same results. I'm thinking fuel pump now, as well. The bulb does soften some, but it does not crumple flat. The fuel pickup was clear; only 2 or 3 of the screen sections had gunk in them and it brushed out with my finger without a problem. The fuel pickup also has no signs of cracking or other holes in it.

Tomorrow morning I'm going to drop it off at the marina for their "free outboard checkup" that they are offering.

 

[tobolamr]

Re: 90 Johnson GT150 - Slowly dies from WOT

The Marina was helpful! They called me back and told me that the repairs would start at $1500. After I put my eyeballs back in their sockets from shock and settled down, I went in to see what was up. I asked them to educate me, because some of what they were saying didn't, initially, make sense.

They figure the carbs need to be rebuilt, and on this model there are 3. The coils are all cracked - and I've been asking myself since then how I had possibly NOT noticed the canyon-like cracks in the coils before then. Sheesh... Lower unit lube was milky, and they are thinking the seals around the screws are most likely bad, but included labor to replace fuel pump, impeller, seals, (those all cost about $75) all in one fell swoop.

The BIG problem didn't even make sense to me until they showed me. The motor mount is shot. Not the transom mount, but the shaft where the outboard pivots & mounts onto the trim bracket. That thing is loose, and the OB shifts notably when you get a hold of the leg. That also explains why I have a little slop in the steering - it's not the cable or steering wheel, it's the OB shifting in the mount by 1/16 of an inch. The parts for the mount repair are $480 new, plus the hours to pull the power head and replace it.

As far as fuel goes, I'm running the on-board tank down as low as I can. I'm nearly to empty. I'm going to then rig up the portable tank and see how that works. I'm also going to pick up and replace the coils, as those I feel comfortable doing on my own.

 

[tobolamr]

Re: 90 Johnson GT150 - Slowly dies from WOT

I replaced all of the coils, as they were badly cracked. That seemed to help quite a bit in smoothing out the running characteristics. Rigged up a temporary tank that I was happy with, and ran just over 5 gallons through without trouble. I'll be hooking back up to my normal tank and testing that when I get a chance... But I'll keep the temp tank rig on hand, just in case.

 

[countvlad]

Re: 90 Johnson GT150 - Slowly dies from WOT

I replaced all of the coils, as they were badly cracked. That seemed to help quite a bit in smoothing out the running characteristics. Rigged up a temporary tank that I was happy with, and ran just over 5 gallons through without trouble. I'll be hooking back up to my normal tank and testing that when I get a chance... But I'll keep the temp tank rig on hand, just in case.

glad you got to the bottom of this,.,,,

 

[tobolamr]

Re: 90 Johnson GT150 - Slowly dies from WOT

Not sure if I'm to the bottom yet or not. I'll find out next time I hit the water, which looks like Thursday evening. Also found one missing zip tie on one carb feed; gonna replace that sucker tonight. Also didn't get the line from the fuel hookup on the outside of the motor to the fuel pump swapped; also going to do that tonight.

 

[jonesg]

Re: 90 Johnson GT150 - Slowly dies from WOT

You can do all that work yourself for peanuts, get the motor mount off ebay.

 

[tobolamr]

Re: 90 Johnson GT150 - Slowly dies from WOT

jonesg,

You are 100% correct. The place I got the boat from has a "used mid-section" for $200 that I could pick up. Problem is that I'm not totally certain that the mounts on that are good. I'm also not completely comfortable with the thought of pulling the power head myself. They showed me the diagram for that motor, and to change the mounts you need to yank the power head. At least, that's how it looks to me... Let me know if this sounds inaccurate... Thanks!

 

[jonesg]

Re: 90 Johnson GT150 - Slowly dies from WOT

Remove P/H to switch out midsection...

I'll look in my manual, maybe one of the experts knows, well of course they know!

To my thinking the only thing that makes it difficult is whether you have a motor hoist, if not you'd do well to snag a used one off craigslist, I got one for $120, they come in very handy for other things besides outboards.

Looking in the manual, I can't see what part is bad from your description.

"Not the transom mount, but the shaft where the outboard pivots & mounts onto the trim bracket. That thing is loose, "

Go to www.evinrude.com
look up parts of elecvtronic catalog and find your engine model number, bring up the exploded diagram and find the part ( look the price up too).
http://12.2.215.22/pub/default.asp?SessionId=8b5f245d2af143339bbee2931b39561a&Lang=EN&brands=EJ

Looking up Johnson 1990 150 I don't see any GT anything, you need the model number to find correct parts, but if they're all alike...?
which part number is it on this parts diagram?
You might have to enlarge the diagram.