1988 johnson 140 looper AIR LEAK IN CARB

[mbecke2]

I ran it today in tub of water and it was idling really high so I put my hand over each carb until WELLA it started idling perfect and didnt miss a beat. It is the top carb which I assume has an air leak and causing a lean running on that cylinder. As long as I held my hand over it, the motor sounded great! I figured it was leaking air where it mounts to the manifold so I used some gasket forming sealant and tried that out, but it didnt work. Also I think I used too much and it was all nasty and getting everywhere on the mainfold. SO I took it on the water and left it on the trailer to see if it would run on a load and IT DIDNT. Started up and idled ok and soon as I put in gear it killed. I want to know if the air leak in one carb would cause the motor to just stall when put in gear, or if this is a seperate issue. This is the issue Ive been facing. Stalls when put into gear. Where exactly can the air leak be besides the gasket on the manifold?? Should I just buy another carb??

 

[reeldutch]

Re: 1988 johnson 140 looper AIR LEAK IN CARB

Why do you think its an air leak?
are you sure the jets are clean and deliver the right amount of fuel?

 

[Joe Reeves]

Re: 1988 johnson 140 looper AIR LEAK IN CARB

It's not an air leak, it's a fuel restriction. Clean that sealer off of the gasket as sealer doesn't belong there and will cause problems.

The high speed jet is located in the bottom center of the float chamber. Clean it thoroughly and carefully with a piece of single strand wire.

Fuel must pass thru the high speed jets first before the fuel can gain access to any other passageway.

 

[mbecke2]

Re: 1988 johnson 140 looper AIR LEAK IN CARB

Thanks for responses. BUt Ive cleaned each carb very carefully at least 10 times and EVERY orifice and jet is super clean. Thats why I think its an air leak. I think the carb is not fitting snug against the mainfold and thats why I suspected air leak. I can take off the carb and check the jets AGAIN but its like Im working in circles here. Think Im goin to start over, Check compression, spark, and fuel and then just bring it to a mechanic and tel him everrything Ive done thus far. Im just frustrated now cause the motor broke in April and Ive yet to get it running since. Ive spent close to 1000 and changed almost every part. Im either losing spark or I have a fuel delivery issue. Tryin my best to use LOGIC to diagnose the problem but Im havin no luck. BUt I do know for sure if I cover my hand on the top carb the motor idles down and sounds perfect.

 

[Joe Reeves]

Re: 1988 johnson 140 looper AIR LEAK IN CARB

There are two (2) air bleed jets located on the front left portion of the carburetor (Idle & Intermediate). Make sure they're where they belong and are the proper size.

 

[mbecke2]

Re: 1988 johnson 140 looper AIR LEAK IN CARB

I just pulled the carb and checked all jets/orifice screws and all were clean. Side gasket is perfect. O ring is perfect. Float level was fine. Jets were NOT swapped. So I took it apart and checked it backwards and forwards and it looked good. So I switched it to cylinder 3 put cylinder 3 at 1 position and the problem followed the carb. Only when I put my hand over the carb does the motor idle down. Do I need to buy a new carb??