Need help 4 stroke.

[P1]

Hi to all i have Johnson 5 hp 4 storke when it is on ideel the motor start to ref untill i put in gear then it's ok but when it reach half gas it begain to ref up again.Can some one help me please

Thank you your help much appriciated.
Regards P1.

 

[HighTrim]

Re: Need help 4 stroke.

What do you mean by "ref" up?

 

[Lion hunter]

Re: Need help 4 stroke.

I'm gonna guess here and I think you have a motor that is trying to run away. This is normally caused by to much air entering the system and causing a lean condition. This can be caused by several things:

Air/fuel mix not set properly

air leak in the system (vacuum lines, fuel hoses, carb gaskets ect.)

Bad fuel pump. As you start to run out of fuel the ratio of air increases and leans it out, then the fuel pump may catch up and it will run properly again.


I gonna roll the chicken bones and say since it's at idle and mid-throttle that it's an air leak somewhere.

 

[P1]

Re: Need help 4 stroke.

Thank you very much for your help you understand my problem because my english is not that good so now i will search for air leak first.
Regards P1.

 

[tx1961whaler]

Re: Need help 4 stroke.

You can search for an air leak with a spray can of carburetor cleaner. With the engine running, spray around the outside of the carburetor linkages, motor intake manifold and other likely places. If the engine changes speed, then you found it. Check for loose hoses and screws first.