Well we got there. Just moved it one tooth and its good. I spoke with the original owner. He swears it was never removed. I could have gotten it close without jumping the tooth. Probably about half of what it was out. My guess is that at Mercury it was installed "close enough" and it ran for a long time like that. Thanks SB! I'll let you know how it runs tomorrow. The black flies were killing me tonight!

https://cimg0.ibsrv.net/gimg/www.off...33b0cbcb19.jpg

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Don't think close enough is correct but that's just me
Can get it precise by building the gadget in the file starting on page 15

Good info.I had to build something similar years back for another engine that escapes me. Was near last years of radio shacks being around.

You and Bup had other good info here too:
https://www.offshoreonly.com/forums/...on-timing.html

Apparently close enough was good enough to get it to run for many years. However, I'm not a good enough kind of guy. It is now spot on per the merc manual 31. I'll see how it goes. If it's not running right then I plan to follow that TSB and build the tool. Seems easy enough.

Holy thread regurgitation!!
 

Basketcase - I know this is a cobweb covered thread from the dark, distant past, but was your problem solved?? I have the same issue of hard starting, it'll even run backwards for a couple seconds when I turn the key off. Once it starts and warms up it starts great the rest of the day. With a timing light hooked up to #1 and the engine warmed up the timing mark is off by about an inch before the timing mark.