'98 Johnson 9.9 stalling

[RYC]

My 9.9 won't stay running at idle for more than a few seconds. If I push the key in (primer) it will come back slightly before it dies. To re- start I have to push the key (prime) in and advance the throttle. It seems run fine above idle now, though a couple of weeks ago it was losing top end - but that issue went away. I also notice my tach will at times will bounce +/- 50 RPMS and others its's rock steady.

The pontoon has an onboard fuel tank, but I borrowed a portable with known good gas and it did the same thing. I checked the fuel filter on the pump and it was clean. Could this be as simple as the fuel pump or do I have an electrical problem?

thanks

 

[fireman57]

Re: '98 Johnson 9.9 stalling

If you suspect your fuel pump when it starts to cut out pump the primer bulb and see if it picks up.If it doesn then rebuild the fuel pump. Sounds to me like you need to give the carbs a good cleaning/rebuild.

 

[OptsyEagle]

Re: '98 Johnson 9.9 stalling

When you say that "you push the key in (primer)" is that the choke you give it when you intially start it up or is that the squeeze primer you do to get gas to the carb before you start it up. There is a big difference here.

If the choke is reviving it, then I would agree that you need to clean out your carburetor. Since it runs fine above idle, I suspect that is the case.

If sqeezing the tank primer revives it then it is a fuel delivery problem. I doubt it but you should be more specific here.

 

[RYC]

Re: '98 Johnson 9.9 stalling

Yes, the action of pushing the key in on the electric motors when cold- starting is supposed to be a primer acting as a choke by injecting fuel behind the throttle plate. I did not squeeze the primer bulb as it wouldn't say running long enough for me to get to it and I didn't have an assistant. After the good fuel acted the same way I had the feeling I was looking at a carb problem. I've never had to remove the carb from an outboard motor so if there are any hints, tips, or warnings they would be appreciated.

 

[fireman57]

Re: '98 Johnson 9.9 stalling

Before you take off the carbs get a buddy and test your fuel pump. Once it starts squeeze the primer bulb, if it picks up then just replace your fuel pump.I'm not saying that you don't need a good carb cleaning too but first things first. The carb comes of easily just take a good peek at it. When you have it off remove the bowl, float, and needle valve. make sure that all passages are clear with a good carb cleaner and some compressed air. You really should soak it overnight in cleaner and blow everything out the next day. You might just have a piece of carp blocking a jet or your needle valve might be stuck. There are ton of threads on here for doing it. Just do a search. If you want a diagram of your carb you can go to ishopmarine or if I'm not mistaken it is on this site somewhere too. Again, just do a search. Carbs are easy but take your time.

 

[RYC]

Re: '98 Johnson 9.9 stalling

Thanks for the advice. The boat is 2 hours from home so I won't get a chance to check anything again until this weekend.

 

[RYC]

Re: '98 Johnson 9.9 stalling

OK, finally got a chance to work on the boat. Checked the fuel pump as suggested and it was OK. Pulled the carb and tore it down and was amazed how much garbage was in the float bowl. I soaked it overnight then first flushed it with a can of carb cleaner, then blew it out with compressed air. After checking the float settings, I put it back on ( only dropped one of the nuts down into the cover), fired it up and after warm- up adjusted the idle mixture. Idles better than ever. Thanks guys!

 

[fireman57]

Re: '98 Johnson 9.9 stalling

Glad everything worked out for you. It's a pain when the thing you are working on is 2 hours away. Enjoy the rest of the summer/

 

[RYC]

Re: '98 Johnson 9.9 stalling

I plan to - and can now!
You guys were right about he carb being easy to remove. If I put a small screwdriver against the end of the stud to capture the nut upon removal and again to guide it back on I didn't have to fish them out of the cover anymore - lesson learned!