Another surge problem on 50 hp johnson

[NX BRAD]

I have a 1989 Johnson 50 hp that is surging @ higher speeds. I have read some of the posts on this board and I seem to not see any person replying back on what fixed the problem. I have replaced the fuel hose and you can squeeze the bulb while driving and it runs ok. The fuel hose is semi hard. I've looked for for leaks and bear wires and I have not checked the spark. It will run on it's own at part throttle but not at wide open or close to it. It worked fine at the beginning of last season. I have replaced the gas tanks a month ago.

HELP HELP HELP

 

[tashasdaddy]

Re: Another surge problem on 50 hp johnson

dirty high speed jets in the carbs. time for 2 carb kits, a through cleaning, removing the low and high speed jets. you need a special tool #317002 $20.00 or do as i did make your own.

 

[Joe Reeves]

Re: Another surge problem on 50 hp johnson

If by your statement of "you can squeeze the bulb while driving and it runs ok", you're saying that the engine runs fine at high speed as long as the fuel primer bulb is being pumped, whereas whoever is pumping that primer bulb is acting as a manual fuel pump. That indicates that the engine's fuel pump is not functioning properly.

 

[NX BRAD]

Re: Another surge problem on 50 hp johnson

I Closed the fuel tank vent and the fuel line started collapsing like their was a great amount of suction. If the pump is bad, would it have this much suction? and if it is bad where would you suggest I find a Pump or kit?

 

[HighTrim]

Re: Another surge problem on 50 hp johnson

The vent needs to be open or you are trying to suck fuel out of a vaccuum, which of course, will not work.

If in fact you can remedy your situation by priming the fuel bulb, your fuel pump needs a rebuild as Joe stated.

Perhaps this will be of interest to you.

http://forums.iboats.com/showthread.php?t=240864

 

[Joe Reeves]

Re: Another surge problem on 50 hp johnson

If the fuel primer bulb will collapse when you close off the tsnk vent, then yes, I would think that the fuel pump is operating properly.

However if this is the case, I can not understand why pumping the fuel primer bulb would have any effect on the engine's performance as you state.

 

[NX BRAD]

Re: Another surge problem on 50 hp johnson

Can you understand my frustration? I know how most things work and this is stumping me. I will rebuild the carbs this weekend and get back with yall Thanks again.

 

[tashasdaddy]

Re: Another surge problem on 50 hp johnson

because the float needle valves are sticking, and it is taking the extra pressure to open them.

 

[PW2]

Re: Another surge problem on 50 hp johnson

FWIW, I have the same engine, and I had the same symptoms. I got a thin guage stainless wire that I rodded out the hi speed jets with and removed a clump of goo of some sort from one of the jets, and it ran just fine after that.

At least in my engine, the jets were a different diameter so you have to get a wire that is thin enough. the first one I got was fine for one jet, but too thick for the other.

 

[tashasdaddy]

Re: Another surge problem on 50 hp johnson

i strip back a piece of extention cord, twist 2-3 strands together.