1977 M440 timing

[houseboater58]

I need some advice, I was going to the set the timing on my 1977 M440's, the manual says 5 degrees BTC, I pulled the rubber plugs out of the top of the bell housing on the rear of the engines to expose the timing marks, they have a mark at TDC and 5 degree and 10 degree marks in both directions. My question is which direction is BTC and is it the same on both engines or is it specific to rotation of the engine? Thanks.

 

[fastjeff]

It's different for both. Since I never remeber which way, I 'boot' the throttle to see which way the mark moves. If advances as the rpms go up, which shows you which set of marks to use.

Jeff

 

[houseboater58]

Thanks Jeff.