Re: Johnson 5hp TD20 ignition timing facts & figures?

[frankr]

First, it seems like you are pretty wise concerning this stuff, but I’ll attempt to address a couple of the things anyway. Yes, it is true that the magnet does not affect timing. That is controlled by when the points open and cannot be changed except by points’ gap, to some extent. And certainly not what you are looking for here.

Piston and cylinder condition affects the crankcase compression. Especially important on a 3rd port engine. Doubly important on these touchy little HD’s

Yes, on virtually all outboards, idle speed is controlled by spark advance/retard, and on most, the carburetor butterfly is closed at idle speeds. You probably are familiar with other motors where the carb has to be synchronized to start opening at a mark on the cam that opens it. I don’t remember exactly when it opens on a HD.

I tossed in the bit about cooling because that was a lesson I learned the hard way….after spending days trying to get one to run properly when I was doing this for a living. Lost my shirt on that job.

Head gasket?? I don’t know. Possibly. Like I commented, "touchy" motors.

30 degrees ATDC? Well, that does seem unreasonable. I don’t have any input on that.

EDIT: Sorry, I got my motors mixed up and was thinking HD instead of TD. But most of what I said still applies. The rest, you can store somewhere.