1975 9.9 johnson,lack of power at wot

[littlelakeden]

Hello everyone.I have a 1975 9.9 Johnson.It ran very well last year but this year it was running rough in the barrel.When I took it out to the lake it ran for about a minute then quit and wouldn't start again.I replaced the points and gapped them .20.I backed out the idle screw 1.5 turns then ran it till it was warm and did the final adjustment till it idled smooth.Now when I'm at wot the motor doesn't seem to rev out and go as fast.Have I missed something when doing the points.Any advice would be greatly appreciated.Thanks for reading.

 

[the machinist]

Re: 1975 9.9 johnson,lack of power at wot

Sounds like you are only running on one cylinder. Did you check the spark plugs?

To test for this, with it running, pull one spark plug wire, replace it & pull the other. If it dies when you pull one, that is the only cylinder that is firing.

 

[littlelakeden]

Re: 1975 9.9 johnson,lack of power at wot

Ok thanks.I will try that.

 

[littlelakeden]

Re: 1975 9.9 johnson,lack of power at wot

I took the spark plugs off one at a time and the motor stayed running.