johnson 140 no power

U

usmma2013

Member
Hey guys,
I have a johnson 140 that has an acceleration problem. It'll run great at idle, 600rpm in gear, but when you hit it it'll rev up to maybe 2k an thats it. Kinda sounds like its bogging. pumping the bulb does nothing. I just rebuilt the carbs, the gas is new, compression is 110 on one side and 105 on the other. all cylinders are firing. It revs up fine on the hose. I just swapped the powerheads on this motor, the rest of the motor is an 85 and I put an 80 powerhead on. Is it possible two different size carbs and its getting too much or not enough fuel because of the jet sizes?
I'm kinda stumped...any suggestions?
 
Not sure if that motor has accelerator pumps on the carbs or not. I had a jet ski with the same issues would idle all day but as soon as u hit the gas would die, but only under a load ( in the water ). Might want to check into that. As for power packs remember left pack controls the right bank and right pack controls the left... I would look into it being a carb issue before replacing a power pack...

Mike
 
It doesn't have accelerator pumps however the set of carbs I used were off the '85 model which had the new style carbs with 4 bleed lines, one to each transfer port cover and the primer system instead of choke. I'd been told that I could use the newer carbs as long as I also switched the transfer/bypass covers over too since they had the nipple required for the bleed line. I'll double check the timing as well.
 
I thought of somethiing else. The primer bulb pumps fuel into the engine you can hear it filling the carbs, but never gets hard. The carbs and fuel pump don't leak, but i think its possible the bulb has bad check valve or theres restriction or a leak somewhere in the line. I'm going to first replace the bulb, then if that doesn't fix it ill try in a portable tank. Then if that works it means theres a problem with the pickup, filter, or line from the tank to the pulp. Anythin im missing from this?
 
usmma2013 said:
I thought of somethiing else. The primer bulb pumps fuel into the engine you can hear it filling the carbs, but never gets hard. The carbs and fuel pump don't leak, but i think its possible the bulb has bad check valve or theres restriction or a leak somewhere in the line. I'm going to first replace the bulb, then if that doesn't fix it ill try in a portable tank. Then if that works it means theres a problem with the pickup, filter, or line from the tank to the pulp. Anythin im missing from this?
Click to expand...


I agree with the others, check your timing first. If you have no luck there, then look at your fuel delivery system.
Just remember, if the check valve(s) in the bulb were bad you would not get fuel to your engine, so it wouldn't run at all. That's the only purpose for the bulb. It pushes the fuel through the hose to your engines fuel pump. It primes the pump. Once the fuel is to your engine the bulb is no longer needed.
However...
If you have a crack in the hose or the bulb then you need to replace it to avoid the engine sucking air, to say nothing of the huge potential for a fire from a hose leaking gas. Also, check the o-rings on the quick connectors where they attach to your tank and to your engine. Make sure there are no leaks.
 
Thanks for the help guys. I'm going home this weekend so I'll be able to work on the boat. I'm borrownin a friends timing light and i picked up a new moeller primer bulb too.
 
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