1976 135hp timing question!

[notyepcars]

I have 1 76 135hp that I just rebuilt and want to check timing. I have the shop manual. Question #1, can I check the timing with the engine running on the trailer with water muffs on?, not in the water. Shop manual shows 20 degrees in gear, has that changed because of fuel quality? or is it still 20 degrees? Thanks

[boats.net]

Yes you can check the timing on water muffs. Timing is set with the engines RPM not load. The fuel quality will not change the timing.