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need help with 1988 e-rude 40hp

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derekJ

New member
I bought this motor about a month ago after it was stored in a shop for 8 years. It runs and idles great on muffs, but once under load it stalls and wont get to full throttle. It does run a lot better if you hold the choke in. I have cleaned the carbs, has good compression, good spark, and replaced the fuel filter and line going from filter to VRO pump. Motor was previously ran with pre-mix, so they did not have the oil tank. I plugged the oil line and disconnected the wiring harness on the pump. What could be causing it to stall and run like crap when in the water? I really need help with this. I just bought all new fuel line to replace everything in it, and hope that maybe somebody on here can help me out with other possible causes/things I should check. Thanks!
 
if it runs better with the choke on, then it's a fuel problem, you need to clean the carbs again. have you pumped the fuel bulb when it's running bad? if so did it run better?
 
I have squeezed the bulb while it was running, and it didnt make any difference. a few questions for anyone that can answer them:

what should the pressure coming out of the fuel pump be?
Will the pressure be different if it is in the water compared to on muffs?

Thanks!
 
1.) with the motor running ,the pressure should be 1 psi at 600 rpms, 1.5 psi at 2500-3000 rpms, 2.5 at 4500 rpms

2.) not that I know of.
 
I am having the same problem with a johnson/evinrude 140hp 1988 . The only thing left to do for me is the fuel pump. The boat starts great and idles fine. when in neutral you can rev the motor just fine without any problems it doesn't cut out or stall. I then put it in gear and it runs fine all the way until half throttle (in gear) You try to give it full throttle in gear and it acts like it is choking or not getting enough gas and dies (in full throttle). and then we put it into neutral and it starts right up and put it in gear and runs great around half throttle , give it full throttle and it dies again we can repeat the process over and over and it does the same thing. We also put a external gas tank on it with marine gas with no ethanol it makes the engine run better but still having the same problems (dies in gear only at full throttle) it doesn't die in gear unless you give it full throttle.
 
have you tried pumping the fuel bulb when going from half to full throttle?

have you tried hitting the choke a few times as it starts to die, ( at half throttle as you are going to full throttle, hit the choke twice and see if the speed picks up, if so you need to clean the carbs.?
 
As for my 140hp I tried hitting the choke a few times also pumping the bulb no luck. What I am now confused about is the fuel pump. According to the motor specks I have the wrong fuel pump on if it is indeed a 1988 Can't locate number on it.
 
I tore the pump apart today and the diaphragm is all dry rotted and pretty much worthless. I have 2 rebuild kits for the carbs and a fuel pump on the way to replace everything. Basically the entire fuel system will be brand new. This should take care of all my problems.
 
I got all my parts in and rebuilt the carbs, then installed the fuel pump. Once it was back together, I took it to a local lake and ran it at the ramp. Motor idled great and ran really good. I believe with a link and sync it will be as good as new. Thanks everyone for your help!
 
Well Good to hear Derick everything on mine is good compression, carburetor. I even am using an external gas tank. Maybe it's inside my fuel pump the diaphragm. Last thing left for me to check.
 
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