1971 johnson 40hp carb keeps flooding. Could do with some ideas.

[pike247]

Hi
I have a 40hp 1971 johnson. When I try to start it the carb keeps flooding.
I have had it to pieces couldnt see anything wrong put it back on but it's still doing the same thing. I bought a second hand carb put it on and that does the same thing aswell . Does anyone have any ideas.

Thanks in advance .

 

[ezeke]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

If the caburetor is flooding the float valve is not working, so you either need a new float valve needle or a new float (provided you have the float set correctly).

 

[tx1961whaler]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

Is gas pouring out of the carb throat, which would indicate a stuck float, or are the cylinders flooding?

 

[pike247]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

Thank for the response. I have stripped the carb down loads of times and checked all the parts. The float pin seems to be ok when i blow into the carb and push the float up I cant blow any air through. When I prime the carb with the bulb it holds fine. Its only when I turn the engine over it floods. It just seems odd that it was doing the exact same thing with the other carb on it. When I look in the front of the carb you see fuel sitting in it and the spark plugs are soaking.

 

[ezeke]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

Does the float float?

 

[pike247]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

Yes I took it out and done a float test indoors. It seemed to be ok. It has me stumped.

 

[tashasdaddy]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

put carb together, now turn it upside down and blow, if you have air flow, you have gas flow. this is how i test all my carbs. pushing up on it is too much pressure.

 

[pike247]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

On one of the many occasions I have had to take the carb off I did do that and the float pin does seem to be working ok. That is why it's so confusing.
I have tried winding the mixture screw right in and slowly winding it out a little at a time so only a little fuel is getting through, but as soon as it is wound out at tiny amount it floods.

 

[tashasdaddy]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

have you replaced the adjustment screw packing?

 

[mafhuntfish]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

Check the reed valves behind the carb in the intake. You might have a broken leaf or something got sucked through the carb and is holding one of them open. Worth a look ......

 

[pike247]

Re: 1971 johnson 40hp carb keeps flooding. Could do with some ideas.

Im sorry I have only been working on outboards for a short while. What do you mean by the adjustment screw packing ? is it a washer or gasket on the outer side of the adjustment screw. (inside the top of the carb).
I have not checked the reed valves for damage but the next time I take the carb off I will have a look. I probably wont get a chance to do anything on the engine now until Friday as work gets in the way of play time
Thanks for all your help so far.