Johnson 15 Hp

[WOJO 1]

I just picked up a 87' 15 HP Johnson that is in great shape. Decided to drain the lower unit then realized (no manual yet) that I do not have any oil to fill it back up except for Merc 90 weight. Is this acceptable for this lower unit. I really don't want to have to do it twice. Will Merc oil work fine?

 

[oldcatamount]

Re: Johnson 15 Hp

Merc 90 weight will be fine, your Johnson won't mind it.

 

[WOJO 1]

Re: Johnson 15 Hp

Thanks for the info.

Can you also tell me what the plug gap is? I bought new ones and want to install but not sure what to set them at. Thanks for any info.

 

[Xcusme]

Re: Johnson 15 Hp

The spark plug gap should be .030......

 

[oldcatamount]

Re: Johnson 15 Hp

I've got a 1988 15 hp Johnson and the plug gap is .040. I tried .030 for a little while until I noticed the unburned fuel pellets while trolling. Re-gapped to .040, and it runs a heck of alot better!

 

[WOJO 1]

Re: Johnson 15 Hp

Thanks all.