Sickly 96 Johnson 150

[Sfritr]

Okay folks, you all have been fantastic in regards to helping me figure out issues in the past so here goes:

In previous posts I stated that my motor was stalling under load.  It starts right up cold, idles down, runs fine.  When you turn the motor off to fish for awhile, turn it back on it starts fine.  Then, when you throttle it will shut off, no sputtering, no coughing, just quits.  I took her in and the shop put her on the Dyno, said they couldn't get it to stall and it ran at a perfect 5500 Rpm.  Now I am questioning the shop because after they "couldn't" find anything wrong I took it to the lake the day I picker her up and without fail, STALLED, just as before.  

To me, it sounds as if it is not getting fuel, can't be.  Wouldn't the Dyno test show this though?   :-/

Any help is greatly appreciated and Thanks

[noway]

I know it's a stretch but call and make an appointment at Lockeman's in Detroit. They are excellent at diagnosing and repairing Johnson Outboards. They actually listen to what you say and their prices are fair.

I had a similar problem with my '96 Johnson Fast-Strike. Turned out to be a carb sync issue.

http://www.lockemans.com/

[AndyPlaysDrums]

Ok, I don't know anything about marine motors, however....

Last year I had the same problem with my lawn mower. After cleaning, checking, replacing everything I could think of, it was off to the shop. I didn't even have it off of my truck and I was told it was vapor lock. The guy took off my gas cap, saw that the insert to keep the gas tank vented was missing, put a new one on, and there has never been a problem since. This was just the first thing I thought of when I read your post. Best of luck!

[Sfritr]

I spoke to the mechanic today.  He stated that it could be a "shift switch"????  I don't even know what that is...  I'm taking her in on Wed.  God help me if he has it for another four weeks.  

[RobbyZ5001]

This happened to me with my 25 hp.. I know it isn't a 150 hp or anything, but sounds exactly the same. I got multiple things done and $700 later it turned out to be the "Brain". Same thing happened where they ran it in the shop and said there is nothing wrong with it. Then I take it back and the same thing happened. So I doubt this helped, but good luck!

[Way2slow]

Shouldn't the dyno make it stall, most likely NO it will not.  Most of the so called "Dyno's" marine dealers have is nothing but a big hydraulic pump that designed to load the motor at max rpm.  A few have the Land and Sea unit that uses a water pump but again, it's to briefly load the motor as they bring it up to top rpm, usually about 15 seconds.  Both of these will overheat if you run the motor too long on them so they would have a hard time running the motor long enough, under a load to simulate a lake run, then stop, wait and start the motor up at a simular load as coming out of the hole.  

There are a couple of things that are common to cause your problem.  Linc and sinc off.  Idle mixture not properly adjusted.  Carbs need to be rebuilt because the mid range orifices are partially clogged or the plastic bodies have gotten to distorted so after they get warm they don't give a good seal where the bowl joins.

Those motors are also prone to what they refer to as heat soak.  When you start to give it throttle, try holding the key in for a few seconds to give it and extra shot of fuel and see how it does.

[Sfritr]

just dropped her off.  Thanks for the info guys.   Also, is there a "cure" for heat soak? I can't tell you all how valuable the information is that is communicated here on a daily basis.  Not only for boat maintanence but everything water related.  I can only hope that I can help someone else out at some point to return the favor.  

[natanestaban]

   When you get the diagnosis.  I am curious to see what is was.   I have an older Johnson and it did the same thing.  I thought it was a fuel problem ie. flow obstruction or water in fuel line etc.   My mechanic said it might be a short in the stator coil that only acts up after engine gets hot.    

   Since, I have not run engine at full throttle only 3/4 once on plane and problem has not reappeared, which makes me think the stator coil was the issue.  

Bama Nate