640 distributor timing

5 Forward · May 11, 2019

What is the correct initial timing for the 640 gas engine. The owners manual says 8 degrees. the shop manual says 4 degrees at 450 rpm. Is it set at 8 degrees engine off, and engine running at idle it advances to the 4 degrees at 450 rpm.

Bern · May 11, 2019

When timing advances, the number should get higher, not lower. So if you start at 8, it should go to 10, 12, 14, etc. as you rev it up.

JDEM · May 11, 2019

As the other guy stated, more advance at the RPM goes up, not the other way around. 134 gas engine is supposed to be at 30 degrees advance with the engine revved up.

5 Forward · May 11, 2019

Yes that makes sense.

Dean · May 11, 2019

4 degrees BTDC at 450 RPM or below.

Dean

640 distributor timing

5 Forward

Member

Bern

Well-known Member

JDEM

Well-known Member

5 Forward

Member

Dean

Well-known Member

Similar threads