Need Help Diagnosing Problems: Johnson 140 Looper

[bryced1]

Hey all, I need help diagnosing a problem I have been having with my Johnson 140 Looper.

It will start and run great sometimes, othertimes it will not start, and other times it will just bog down and die while running. I have noticed that when trying to start, if you place your hand in front of one of the carbs, you can feel blowback. From that same carb if you tilt the motor up, fuel comes out. I have checked the compression and all is good. I have also recently rebuilt the carbs. I have also noticed that when cold and it first fires up, it is only running on 2 cylinders for a second or two and then begins to fire on all 4.

I am currently away from the boat but will be returning home for a week and would like to get her up and running well again. any thoughts or places to really begin?

Thanks in advance!!

 

[GCarlover]

Re: Need Help Diagnosing Problems: Johnson 140 Looper

Sorry that no one even tried to help you. I had the same problem plus a surge while on plane. Two carbs were spitting back and leaving fuel in the air silencer. The forums on Marine Engine.com and others had some info. Ordered a new set of Boyesen reeds. The gaskets under them were leaking. Make sure you clean out the Locktite in the threads with a tap. use new intake gaskets with good sealer. You need to richen the idle by going to smaller idle air bleeds. use locktite and don't over tighten. They may show a little light through. They will seat when running. Your engine has Fast Start if it's 88 and newer.(computer advanced) Not sure about running on two. It's supposed to when S.L.O.W. kicks in when overheated. Any one, need help on the warm up procedure?

 

[boobie]

Re: Need Help Diagnosing Problems: Johnson 140 Looper

This post is over 90 days old. Pleased the rules at the top of the forum. Thank you.