89 johnson 25hp tracker power loss

[philmay75]

Hi,

I have a question about a boat I just bought. Would appreciate suggestions.

The 89 Johnson 25HP 2-cycle motor ran great the first day. Took it out for a couple of hours. Very responsive, touch the key and it starts. around 30ish mph. Put in gas (supplied with the boat) and took it out the next day and in the middle of the drive across the lake at WOT it throttled down and started to die. Couldnt restart. Thought it might be bad gas. Got new gas and remixed. Drained carb bowl, pumped gas through and checked fuel lines and filters. Replaced plugs and tried again. Same result.

Today, I checked compression (ran it for a bit, took out plugs, opened throttle, and turned it over.) Both cyl. show 70psi compression, consistently. (assuming I did this correctly).

After I put it back together, I took it back to the lake, and it fires up fine now, but seems to only run at about 60% power. Progressing to WOT hesitates a little, but will throttle up now, but not back to where it was.

Thanks

 

[tashasdaddy]

Re: 89 johnson 25hp tracker power loss

check your spark on each plug when it acts up. did the motor sit for a while before you bought it. it sounds electrical, either coils or power pack heating up and failing. the reason to check spark, when it acts up.

 

[philmay75]

Re: 89 johnson 25hp tracker power loss

Thank you for your response.

Sorry, I forgot to mention that I bought a spark tester and had my GF turn it over. Saw 4-5 sparks go by on each plug.

Another thing. The horn (I think this model has an overheat horn with an RPM limiter) was acting up that day, but the motor wasn't over heated. Any suggestions on testing whether that limiter might be the issue? That would go along with your theory of it being electrical, right?

 

[philmay75]

Re: 89 johnson 25hp tracker power loss

Don't know how long it sat before I bought it. is 70psi compression too low for this motor?