Dial Indicater Link and Sync Question Merc 100 HP 1989

[w2much]

My dial indicater has 5.5 millimeters of travel. It was used to tune motorcyles and had has the proper screw in attachment to fit the plug hole on my motor. My Seloc manual says to find .600 " BTDC then move back to .544" BTDC to set the timing mark correctly. Do I need another indicater with an inch of travel or can the one I have be used? .600" equals 15.23999 millimetrs, .544 equals 13.8176 . The difference being 1.4223 millimeters. This is in reference to my 1989 100 HP Mariner/ Mercury

 

[Laddies]

Re: Dial Indicater Link and Sync Question Merc 100 HP 1989

The reason to ck the timing pointer at .544 is to make sure that is adjusted properly for TDC it is easier to get proper adjustment by doing it a little way down the bore rather than guessing where it is at TDC. If you don't have a dial indicator with enough travel you can do it the old way and use a timing stop to find TDC by rocking the crank back and forth on the stop to find TDC, although it is not as accurate. Frankly I have never saw one incorrect from the factory inless some tinker moved it

 

[w2much]

Re: Dial Indicater Link and Sync Question Merc 100 HP 1989

Laddies, Thank You. What is a timing stop?

 

[Laddies]

Re: Dial Indicater Link and Sync Question Merc 100 HP 1989

A timing stop you screw in the plug hole till the engine won't quite turn over by hand rotation then mark the flywheel at the timing pointer and reverse rotation by hand the other way, mark the flywheel at the timing pointer again. TDC is exactly half way between the two flywheel marks. The stop can be a simple as a plug base with a bolt welded into it or factory made one that is adjustable for depth