Fish-Hawk.Net

Hello all,

Been having an acceleration issue with my 1991 (possibly 1992) Johnson 15hp. Machine ran great all summer. Had it out on Christie Lake at the end of August and it started to do this:

https://drive.google.com/file/d/0BwIHi5 ... sp=sharing

I had my brother take the video so I could accurately describe the issue. What you see is me twisting the throttle like normal, but at a certain point it just cuts out and goes back to idle. Runs fine in idle, reverse (though I never got the RPMs up too high) and then at low speed in forward gear.

What I have done:
- Cleaned out the carb, including the high-speed jet.
- checked fuel pump for leaks

If anyone has experienced anything similar or might know the issue, please help! I am handy (mainly because I am poor) and I have a 1981 15hp as a parts engine. I put a lot of time into that machine and getting it running, pee pee me off when it just decides to quit one day. Such is the life of a marine engine owner I guess.

Check the mechanical linkages between the hand grip and the motor?

When troubleshooting I like to start by eliminating the obvious. I'm no pro but this sounds more like an electrical issue rather than a fuel supply fault. Specially with the sudden loss of power. I'd start with the plugs and then go to other ignition parts that could be failing at higher revs, like coils, stator or even rectifier. Looking online it seems like most of the parts from your spare engine are compatible.
btw it should be easy to tell the year of your engine by the serial no.

Good luck with it. Cheers

So you think electrical eh? I feared as much.

I will test with a multi-meter and see if I can narrow it down - appreciate the replies!

I had a similiar issue but once mine died down it wouldn't rev back up.

I actually cleaned the carb twice to get mine to work. I ended up soaking it over night and making sure ball in the carb wasn't sticking. After that i pored a full can of seafoam in the tank and ran it straight for 45 minutes to give it full cleaning.

Check this website out: so much info on it http://www.leeroysramblings.com/Outboar ... icles.html

Sorry if some of these suggestions seem obvious, but just listing them all
- Try changing the spark plugs
- Check the gas tank to make sure your not sucking up debris
- Check the prime bulb. is loosing pressure?
- clean the carb again, and let it soak overnight or even longer. even pick up one of those compressed air cans for cleaning out keyboards, it will help blow out any of the debris in the jets
- Sometimes the fuel pump diaphragm gets stiff with time and doesn't operate as it should.
- Check all your fuel lines (cheap to replace)
- Run it with the cowl off and see if you notice anything slipping once you have it reved up all the way
- I was told when mine was having issues it was a sign of you power pack be going. (hopefully not its an expensive part)

had the identical problem on my 15 hp johnson........Had a friend replace the diaphram, change the plugs and used seafoam on the carb.....Ran fine afterwards....Was caused by my forgetting to push in the choke and running it with the choke out , once... oops

Cheers guys, thanks for the replies. I believe the problem is electric, more than likely the coils. I will be checking the spark tonight along with the plugs and pretty much the whole electrical system.

I had the same problem. Mine was a little glob of water in the tank. When I accelerated and the boat started to plane the little glob would roll down to the fuel pick-up in the tank. The boat would slow down and level out as would the tank, the water glob would roll away from the pick-up and the motor would run fine. Accelerate again and it would repeat. The motor did this for quite a while until I discovered the little ball of water. It was a "little" ball of water. Removed the water and the problem went away. It was too simple. To check it out, turn your tank so the pick-up is higher than the bottom of the tank and it will run fine. Hope this help.

Just for info, you can get a can of compressed air for $3 at the dollar store.