1990 25hp johnson model J25RESB

jgilpin

Cadet
Joined
Sep 30, 2019
Messages
9
Looking for some help on the above motor. My uncle bought it new years ago. It began giving him issues with not running properly. He cleaned the carb numerous times and said it would run good then go to crap. He eventually got fed up and just bought a new one. So, I got it pulled the carb, completely disassembled it and soaked it in carb cleaner for 48 hours. Oh and it was clean already when i took it apart. After soaking I blew it out with carb cleaner followed with compressed air. The thing was clean as a whistle. I put a new carb kit in replacing the float valve and seat etc. Also put on a new fuel pump.

I put it back together and it started up great. Thought I was good to go. I purchased a brand new fuel bulb and line and put it on a fresh tank of gas. I later put seafoam in the mix to try and help it..........i guess you can see where this is going.

anyhow, it would not run right. I did some research and made sure the linkages are all adjusted correctly. They were not but they are now. It will sit out there and idle for an hour or until I turn it off. But upon speeding up the engine it will soon start sputtering and die likes its running out of fuel. I have also replaced the fuel lines. Same symptoms exist.

So, the fuel bulb it pumps up tight as a drum with no leaks to be found. When running the fuel bulb goes soft. I have tried gently pumping it and it does not seem to fix the issue of it running like junk when revved up. I know sometimes new parts are bad and maybe the new fuel pump could be junk but I don't want to replace parts I already replaced. I guess I could go through the carb again but I really don't think that's the issue. I'm not a professional mechanic but I have rebuilt many a carburetor.

Any advice would be greatly appreciated.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,895
We read it all the time.----" cleaned the carburetor and motor still runs the same "-------Fact the primer bulb does not need to be hard when motor is running !-------Post compression numbers.----Does spark jump a gap of 3/8" or better on both leads ?----Are you sure throttle plate is not opening too early ?----Post picture of the stop on that rod at the tower shaft.----Picture of that in the idle position.----You have checked the flywheel key ?
 

jgilpin

Cadet
Joined
Sep 30, 2019
Messages
9
I soaked the carb in Carb Dip for 48hours blew it out with carb clearner followed by compressed air. Guess I could go through it again but I feel the Carb isn't the issue. I will get my compression tester and check that. I do not have nor access to a spark tester that will test the gap jump. I have not checked the flyweel key but I certainly can. Will a special tool be needed to pull the flyweel.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,895
Remove top sparkplug.----Turn flywheel till #1 is at TDC.----Check timing mark on flywheel.----A sheared key throws timing out.
 

jgilpin

Cadet
Joined
Sep 30, 2019
Messages
9
thank you racerone. It is showing 20 degrees at top dead center. Does that sound right? Took some pictures of linkage. I'll try to attach them here in a bit.

I am unable to upload photos
 
Last edited:

flyingscott

Fleet Admiral
Joined
Apr 8, 2014
Messages
8,229
thank you racerone. It is showing 20 degrees at top dead center. Does that sound right? Took some pictures of linkage. I'll try to attach them here in a bit.

I am unable to upload photos

No that does not sound right should be at 0.
 
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