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Hi all took apart a lawnmower with a tecumseh engine ( TVS120-63920L) the cam has a timing mark the crank has none. It has no bevel, dot nothing. it is the type where the gear is pressed on. Even if the gear was mounted upside down you can't see underneath because part of the crank prevents this. So now what? I'm ready to throw it in the trash

Thanks for the pics...but as I stated there are NO marks on the crankshaft to line the camshaft mark up with

anyone else have any ideas?

Give me til tonight. Ill post my pic of my Tecumseh. Yours might not have the mark but at least with my pic u can see what position your crank should be in.

By the look of that second picture you need to line up the cam marking with the crank Key Way so there may not be a marking.

OldDiyer said:

By the look of that second picture you need to line up the cam marking with the crank Key Way so there may not be a marking.

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That looks and sounds right

The place on the cam exactly between peak lift on the cab lobes is where TDC on the crank occurs.

Thanks OldDIYer there is no keyway this is pressed on.

Cpurvis..guess I'm not following in words...pic would be more helpful

See the red vertical line. It represents the cam position when the crank is at top dead center and the cam is almost finished closing the exhaust valve and beginning to open the intake.

With the piston at TDC, that red line needs to go through the centerline of the valve lifters. In this view, the cam needs to rotate about 45 degrees clockwise to be in the correct position.

Thanks cpurvis but trying to adjust a small engine with a generic car engine pic just won't work. You could be off by a lot on the timing.

Can you post a pic or pics of your gears?

FWIW, there is no such thing as a 'generic car engine pic.' There is nothing on that picture that says it is. It's the end view of a cam on a 4-cycle engine, period.