Problem with Old Johnson 6hp: has varying r.p.m

[charles.wahlin]

My old 6hp Johnson Seahorse has a problem with varying R.P.M when throttle over 1/2.<br /><br />On lower speed it works fine, but when increases throttle the problem starts.<br /><br />R.P.M is going up and down without misfires.<br />I can also see that speed is going up and down.<br />I don't know the age of the motor but I guess it is 20-30 years old. It has 2 cylinders and is equipped with a electrical power output.<br />Can anyone give me an idea of what is wrong.<br />/Charles Wahlin, Gothenburg, Sweden

 

[JB]

Re: Problem with Old Johnson 6hp: has varying r.p.m

Ahoy, Charles. Your problem is probably related to fuel. Possible causes are air leaking into the hoses, fuel restriction in the path from tank to carburetor, failing fuel pump, water in the fuel and clogging in the carburetor. Careful inspection may find the fault, or you may need to overhaul your fuel pump and/or carburetor.<br /><br />If you will supply us with the model number from the engine plate we can probably tell you exactly what year it was made. This will be helpful in purchasing parts.<br /><br />Good luck. Standing by.<br />JB

 

[charles.wahlin]

Re: Problem with Old Johnson 6hp: has varying r.p.m

Okey J.B here comes the numbers.<br /><br />Model: 6BAL79E<br />Serial:B031297<br /><br />What year is it?<br /><br />I still haven't found what causes the my problem. I shall now investigate the carburator. I maybe have a small leakage of fuel there. I can see fuel on the outside of carburator. We will see.<br /><br />/Charles

 

[jdenton]

Re: Problem with Old Johnson 6hp: has varying r.p.m

Try pumping primer bulb while running. I went through a friend's 70's model 9.5 Johnson that had been sitting for years last night. New impeller, carb cleaning, exhaust clean out, etc. Started right up on first try in tub, but died instantly. Grabbed his spare tank and hooked to motor. Fired up and run like a top. Ready to take out for lake test. <br /> I have been reading this forum for quiet a while and probably couldn't have helped my friend with his motor without all the help the people of this forum have given. The feeling of accomplishment you get when you fix something like this for a friend is a great feeling. My thanks go out to everyone on this board.<br />Joe