1989 25HP Johnson Backfires and Prop does spin - Help?

[gottech]

Hello all,

I have a 1989 25hp Johnson Outboard (Model: J25RCEM) that backfires when I throttle it up. I changed the plugs and still doesn't fix the problem. Could it be the fuel/oil mixture? Also the prop spins very slow. What do y'all think it could be?

Thx Edwin

 

[david_r]

Re: 1989 25HP Johnson Backfires and Prop does spin - Help?

how much throttle before the backfire 1/2, 3/4, or maybe just above idle?

sounds like a timing or too much fuel issue.

have you hit anything while in the drink?

i had a buddy that hit a rock, good anough that it killed the motor, so we went to work checked EVERYTHING.....long story short it sheared the flywheel key.

 

[DJ]

Re: 1989 25HP Johnson Backfires and Prop does spin - Help?

Is it a backfire (through exhaust) or a sneeze (through carb. throat)?

A backfire is too much fuel and/or timing off. A sneeze is a lean condition.

Sounds like your prop hub is spun. Draw a line on the prop. shaft and a corresponding one on the prop hub. They should stay aligned after running it.