Timing for 1982 75hp

[Todd Humphreys]

I purchased this rebuilt motor recently, upon doing my own regular maintenance, I decided to check the timing at idle and WOT. Idle was TDC as indicated in the manual, but the WOT timing was set at 14° BTDC. The manual states 19°+/- 1 BTDC. Is there any reason for the mechanic who rebuilt the motor not to set it according to spec for breaking in purposes. What are the consequences of over advancing the timing past OMC spec? Is it possible to melt a piston or just begin to loose hp past its maximum advance.<br />

 

[Todd Humphreys]

Re: Timing for 1982 75hp

Is there anyone out there????

 

[andbham]

Re: Timing for 1982 75hp

As cadet to cadet (in my case, space cadet) I'm out here. To take a chapter from an auto experience I had, you don't want to bend the rules too far. The engine tends to eat itself.<br />andbham

 

[Dhadley]

Re: Timing for 1982 75hp

Retarded timing can be as bad as timing advanced too far. Especially on a looper.<br /><br />Now, that being said -- describe exactly how you are checking the top timing.

 

[Todd Humphreys]

Re: Timing for 1982 75hp

I have no way to check the timing running WOT with a test wheel. My thinking was to manually advance the timing by unhooking the linkage and holding it fully advanced against the stop, and with a timing gun shoot the timing while someone else was turning over the engine (not running). Before doing this I made sure the timing pointer was at top dead center of the #1 piston by using a screwdriver and rotating the flywheel by hand. This might seem little primitive but I hoped it would give me a close estimate of what the timing is and to set it to OMC specs. Fingers crossed.

 

[Dhadley]

Re: Timing for 1982 75hp

Doing it that way will show total less about 4 degrees. I would say its pretty close to 19 when under a load.