Cam Positioning

[TimStarforth]

I recently replaced the impeller on my 81 Mercury 50hp outboard, and the cam slid off when replacing the lower unit....now in the water, it is running fine in forward gear, but the motor lifts up when the boat is in reverse, and I saw a thread regarding the cam positioning, which I am thinking is my problem. So, with that said, how do I go about positioning the cam in the correct way. It seems like it is off one or two teeth. Thank you very much! I am almost ready for spring!

 

[carholme]

Re: Cam Positioning

Yes, it sounds like you have the cam a few splines off. Here is a link to the condensed version of the Clymer manual. Download it soonest to your computer as the link is short lived.

Small Engine Repair Reference Center Home: MERCURY - MERCURY FOUR-CYLINDER MODELS (1969-1989).

See fig. M12-64 on page 287 which is pretty self explanatory. If you have a problem, let us know.

Gerry

 

[mercurymang]

Re: Cam Positioning

Fortunately I think that shaft is square so there are only 4 possible ways for it to go on. I had the same issue with mine when I first got it. I removed the LU and turned it 90 degrees and it fixed it.

 

[Maxz695]

Re: Cam Positioning

If this is the front of the LU ^ the hi dentent will be facing this forward most part of the LU in reverse. The center of the cam in neutral ^ and the lowest part of the cam Fowards ^ to the front fowards mot part of the LU. Test by shifting into Fowards. The prop ratchets one way and locks in the other. In Neutral the prop spins both ways freely. In reverse the prop will lock in both directions.

 

[Laddies]

Re: Cam Positioning