1974 70 hp Johnson no mixture adjustment screw?

[huntxtrm]

I have a 1974 Johnson 70 hp. It does not have mix adjust screws. It just has plugs over jets, where I would think they normally should be. Is there no adjustment on these? Motor seems to run a little rich. Or do you have to change out jets? Thanks

 

[F_R]

Re: 1974 70 hp Johnson no mixture adjustment screw?

All fixed jets, no adjustments, nor any needed.

Spark/throttle synchronization affects the richness / leaness to a limited degree.

 

[huntxtrm]

Re: 1974 70 hp Johnson no mixture adjustment screw?

what's a good repair manual to have for this motor? Or a tuneup guide? I want to make it run smooth possible. thanks

 

[boobie]

Re: 1974 70 hp Johnson no mixture adjustment screw?

Get an OEM Factory Service Manual and it tells all.