Engine Bogs down - 75 HP Johnson, 1981

[ericulvila]

I replaced all the plugs wires and coils on 3 cyl 1981 75 hp. It ran great for a while (most of the summer) but recently bogs down when trying to go on plane.

If I burry the throttle in gear it feels like no power no rpms, I can rev the engine to full rpm out of gear. Carbs where rebuilt and link and synch completed.



Please let me know what to check.

 

[timguy]

Did it get worse slowly or all at once? Compression test? Jets removed and properly cleaned?

 

[flyingscott]

Also do a cylinder drop test or a spark test. The spark needs to jump 7/16".

 

[ericulvila]

Seems like it was all at once, compression test showed 135 all three. I could not remove all three jets in each carb. I did only the ones that I could unscrew.

Soaked all carbs in Berrymans cleaner and installed new carb kit. Also added a new fuel pump and fuel line

 

[ericulvila]

I have spark gap tester showing blue spark set to 7/16

 

[flyingscott]

Try this make a mark on the hub of the prop and see if it is slipping.

 

[ericulvila]

Interesting, will do - also forgot to mention that I am getting some water in the gear case, not terrible but I keep an eye on it and change about 20 hours.