Strange Johnson issue, looking for advice...........

Fishhook2120

Cadet
Joined
Aug 8, 2008
Messages
21
I have a 97 Johnson 90hp. It runs great most of the time. But after running for a while on the lake, it will not restart.

Last trip out: Put boat in early in the morning, and ran 20 min to bait hole, shut it down, caught bait, and started up and took off for a 30 min run back to where I was going to fish. Started and stopped the engine several times while looking for fish, and fishing. Started back up and ran to marina, was out of boat for 10 min, and would not start back up. Cranks and cranks, sputters and trys to start, but fuel will not ignite. (my opinion) So I use trolling motor to get back to ramp. Let the boat sit in the garage for the week, pulled it out this w/e and fired right up and ran perfect.

Trip before that: Put in, ran off and on for 4-5 hours with no issues.

Trip before that: Put in and ran great for several hours, but after fishing a while with engine off, it wouldn't restart. Same as last trip, used trolling motor (glad I have a good one) and back to trailer. Sat in garage all week, started right up after sitting.

So, hoping one of you guys can lead me in the right direction, I am not a engine man, but will gladly take it somewhere once I have an idea of my problem. I have run several tanks of fuel through it during these trips, and I have tow filters hooked up. I have correct grey fuel hose, and use ethenhol treatment in fuel. I have changed plugs during this time also.

I have waited over an hour while trolling before trying to restart once the issuse happens, but no change, only after a few days will it start. I have also seen fuel leaking around the cowl. (I mix oil in tank) so I feel that is a carb overloading problem, but hate to rebuild them if I have another issue going on. And from my limited experiance, the boat shouldn't be able to run so perfect with carb problems.

Thanks for any lead on this.

Fishhook2120
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,142
Re: Strange Johnson issue, looking for advice...........

I have seen that symptom, or similar symptoms on motors of that design. I do not yet have a fix. Next time try warm-starting the motor with the throttle advanced a bit. See if that helps. I do that and let her run 30 sec in neutral and that seems to clear it up....
 

Fishhook2120

Cadet
Joined
Aug 8, 2008
Messages
21
Re: Strange Johnson issue, looking for advice...........

Thanks for the input. I tried starting it with the idle lever up and it wouldn't work either last week, it would fire on the "choke" and shut back down as soon as that choke fuel was burnt. But with lever up, it wouldn't even do that. I tried firing it and slamming into gear to take off, but that didn't work either. Very confused.

Thanks

Fishhook2120
 

Fishhook2120

Cadet
Joined
Aug 8, 2008
Messages
21
Re: Strange Johnson issue, looking for advice...........

Any other ideas ?

I guess I will take it to a shop and see where it goes from there. I figure a carb rebuild and I hope that is it.

Thanks

Fishhook2120
 

stromis37

Recruit
Joined
Aug 6, 2012
Messages
1
Re: Strange Johnson issue, looking for advice...........

Any other ideas ?

I guess I will take it to a shop and see where it goes from there. I figure a carb rebuild and I hope that is it.

Thanks

Fishhook2120

I am a marine technician and recently had a similar problem. The carburetors and bowls being plastic lead to warping, which leads to an air leak, which leads to poor fuel delivery. You need to isolate and find out which cylinders are not receiving fuel.. easiest way,...get the motor up to a speed where it will stay running and put two fingers in front of the throats of the carbs. If one or more pick up, it most likely is leaking air. Try that for starters.
 

sunwest

Cadet
Joined
Jun 16, 2012
Messages
26
Re: Strange Johnson issue, looking for advice...........

I have a 97 Johnson 90hp. It runs great most of the time. But after running for a while on the lake, it will not restart.

Last trip out: Put boat in early in the morning, and ran 20 min to bait hole, shut it down, caught bait, and started up and took off for a 30 min run back to where I was going to fish. Started and stopped the engine several times while looking for fish, and fishing. Started back up and ran to marina, was out of boat for 10 min, and would not start back up. Cranks and cranks, sputters and trys to start, but fuel will not ignite. (my opinion) So I use trolling motor to get back to ramp. Let the boat sit in the garage for the week, pulled it out this w/e and fired right up and ran perfect.

Trip before that: Put in, ran off and on for 4-5 hours with no issues.

Trip before that: Put in and ran great for several hours, but after fishing a while with engine off, it wouldn't restart. Same as last trip, used trolling motor (glad I have a good one) and back to trailer. Sat in garage all week, started right up after sitting.

So, hoping one of you guys can lead me in the right direction, I am not a engine man, but will gladly take it somewhere once I have an idea of my problem. I have run several tanks of fuel through it during these trips, and I have tow filters hooked up. I have correct grey fuel hose, and use ethenhol treatment in fuel. I have changed plugs during this time also.

I have waited over an hour while trolling before trying to restart once the issuse happens, but no change, only after a few days will it start. I have also seen fuel leaking around the cowl. (I mix oil in tank) so I feel that is a carb overloading problem, but hate to rebuild them if I have another issue going on. And from my limited experiance, the boat shouldn't be able to run so perfect with carb problems.

Thanks for any lead on this.

Fishhook2120

I agree with stormis in away not sure if that your problem but for sure the right direction... Is whats happing it's fowling out your plugs ..put new plugs it will crank right up and run good... for awhile till it fowles thows. so look for whats fowling them out. if you find nothing start checking your ignition parts cause they will also start acting up once warmed up /hot. Good luck
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,142
Re: Strange Johnson issue, looking for advice...........

Stromis, You are assuming the air leak is between the carb body and the intake manifold? Why would this only happen upon restart, after the motor was run a while and then shut down a while? it runs fine after you get it restarted and run for a few minutes. Does the warpage go away?
 

DC20

Petty Officer 1st Class
Joined
Dec 5, 2007
Messages
361
Re: Strange Johnson issue, looking for advice...........

Stromis, You are assuming the air leak is between the carb body and the intake manifold? Why would this only happen upon restart, after the motor was run a while and then shut down a while? it runs fine after you get it restarted and run for a few minutes. Does the warpage go away?

Good point Chris. I wonder if it has anything to do with the fuel sitting there getting hot, or a vapor lock?
 
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