Johnson 35 hp cutting out at Wide open throttle.

[flintcreek]

I have a 1981 Johnson 35 hp and it is cutting out at wide open throttle. Have found out that if I pump the bulb on the fuel line every 15 seconds or so it will run without cutting out. I believe it is getting air from somewhere. Any ideals. Runs at low speed just fine.

Things I have done.
Changed gas tank and fuel line.
All new fuel lines under the hood.
Rebuilt fuel pump.
Cleaned carburerator.

Help guys what am I missing?

Thanks in advance.

Flintcreek.

 

[crazymanme2]

Better double check the things you've done because pumping primer ball still means lack of fuel.Who rebuilt fuel pump?Check your connections again for air leaks.Try to rig up a simple fuel system with a hose & your primer bulb.Just stick hose in a quart jar to primer bulb to motor.You could use a gallon jug,but make sure your hose is in the gas & try that.

 

[flintcreek]

Thanks, I will start going back through and looking at everything I have already done. I ordered a carb kit, going to make sure it is not trash in the high speed jet, and pumping the bulb is some how moving it out of the way? When I went through it earlier I did not have a gasket kit and did not take out the knock outs and clean the high speed jet. I rebuilt the fuel pump myself, and it was my first ever so it might be questionable. I have a good one on a 18 hp I will see if it will bolt up and work (looks smaller), if not I may see if my brother will loan me his tank, hose and fuel pump off his 35. I did think I would also probably this afternoon take off the by-pass plates and re-seal them to make sure it is not sucking air at the by-pass plates.

Thanks,
Flintcreek

 

[crazymanme2]

Did your fuel pump have little springs in it?

 

[flintcreek]

Not sure if it had little springs or not, but I believe it did it has been a month or better since I rebuilt it.

Flintcreek

 

[crazymanme2]

Go to this site,it shows the break down of (I think) your fuel pump.If not let me know.

https://www.sschapterpsa.com/ramblings/Rebuilding_fuelpump.htm

 

[flintcreek]

Crazymanme2,
You may have put me on it earlier, when you said I might should go back through what I had already done. I decided to buy a carb kit and go all the way through the carb, I had cleaned it without buying a carb kit and put it back together. Did not see anything in the carb, but the fuel line coming to the bowl of the carb was sort of kinked and almost collapsed. Thinking this may be collapsing at WOT and when I pump the bulb it forces it open. What do you think? I replaced this fuel line and it looks much better now. Hope I can run it later this week, had planned on taking it out tomorrow and doing a little pre-fishing for a tournament this Sat. But my fishing partner called me this afternoon and rescheduled for Thursday and he is trading for a Ranger tomorrow and wants to run it Thur. So it could be next week before I can get mine on the water.

Thanks for the help, I will post and let you know if this fixes it as soon as I get it on the water for a run.

Tight Lines..
Flintcreek

 

[thudpucker]

One more place to look.
Right where the fuel line fits onto a hose barb, there's a screen and a cork gasket.
That hose barb fitting is famous for cracking where the screw (large screw with a nickle sized slot) hold's it down. And that Cork gasket will begin to leak air as the pump tries to force air into the tank or suck fuel out of the tank (depends on if you have two hoses or just one)

 

[crazymanme2]

Yes that kink could do it.Good luck & keep us posted

 

[flintcreek]

Update, took the boat out Saturday about day break to try the motor out and do a little fishing. Since I had rebuilt the carb, I had to adjust the low speed needle to get it going first off. Took me a little longer than it should have, but after the carb was adjusted out it ran good. Took it for several long runs at WOT and did not have to pump the bulb, so it appears that it was the line on the bottom of the carb sucking together where it had gotten kinked because it took such a sharp bend up to go into the carb.

Thanks to everyone that helped.

Flintcreek..