Reply To: getting my Johnson MD-39 running again

[Hugh Davis]

Thanks Stanley!!

There is what appears to be a freeze plug on the top side of the carb (looks like brass) How can I remove it to clean out the channel tube?

Is there a gasket for the top of the carb bowl? the top is held on by spring clip and I would think will slosh out gas when we eventually are out jumping waves on the lake.

what is factory setting for HS needle valve?

I plan on using leaded gas only in this engine, what octane is appropriate? Racing fuel is available here, should I use racing fuel?

what is proper compression on an engine of this age? If I don’t have to take the head apart, I won’t need a gasket that I probably will have to have made or have to replace rings if needed???( if I can find them!)

Water intake mechanism is befuddling me. I’m not sure how it works so I’m hesitant to take it apart, only to find irreparable parts. Does it need to be serviced? I won’t know it’s sucking up water until I start cranking in it and she starts sucking.

what weight oil should I put in the foot?

I found a MS-38 for sale, I am pondering purchase so I can have a source of parts but I don’t know if MS-38 and MD-39 parts are interchangeable. Are they?

If I can get her running, I think my OCD will kick in and I’ll want to paint and decal her for posterity and my son/future scion. Not sure where to look for that information.

Thank you in advance!!

Have a great weekend!

Hugh