78 S&S timing

[ctjahn]

iPhone signal is weak to search forums.

What should the timing be on a 78 MC 351 elect ign?

I thought I set it to 10. It's loosing power after 3000 rpm and over 30 mph. (after elect ign and timing adjustment

Saw two MCs up on Nokomis flow age yesterday: BF 200 and a Mia 80s S&S


Cj

[thatsmrmastercraft]

10 should be good as long as it doesn't ping. Have you checked if your secondaries are opening? Could be the weights in the dist aren't giving you full advance.

[TRBenj]

Let me guess, Pertronix? If so, throw it in the garbage! Ive seen it happen before (several times). Going back to points fixes the issue.

10 initial is fine.

[ctjahn]

Thinking back I think I timed it looking at the side rather than top down... There must be a reason it is falling on its face at the top end....will try retiming looking down from the top and give it a go... We don't NEED to go faster than 32 but.... It's not right.

Cj

[TRBenj]

Originally Posted by ctjahn

Thinking back I think I timed it looking at the side rather than top down...

[ctjahn]

Originally Posted by TRBenj

Becayse it is a pointer and the timing marks are viewable from multiple perspectives; I wonder if it matters if you view the marks from the top or at a 45 degree angle; which in fact will affect the actual timing when using an old timing light... Make more sense?

[thatsmrmastercraft]

Originally Posted by ctjahn

Becayse it is a pointer and the timing marks are viewable from multiple perspectives; I wonder if it matters if you view the marks from the top or at a 45 degree angle; which in fact will affect the actual timing when using an old timing light... Make more sense?

I'm thinking you could be off by as much as 5 degrees.

[TRBenj]

No way. The pointer and balancer arent far enough apart to be able to see any difference in timing readings when viewed from different angles.

You didnt answer my question- did you install a Pertronix EI kit? If that corresponds to your reduced performance, it wouldnt be the first (or second) time Ive seen that happen.

[thatsmrmastercraft]

Originally Posted by TRBenj

No way. The pointer and balancer arent far enough apart to be able to see any difference in timing readings when viewed from different angles.

You didnt answer my question- did you install a Pertronix EI kit? If that corresponds to your reduced performance, it wouldnt be the first (or second) time Ive seen that happen.

Using my non-scientific measuring capabilities available on my desk (ruler, tape measure and a paperclip) I calculate that if the timing pointer is 1/4" from the damper pulley, and you view from a 45 degree angle to the timing mark, what you see is approximately 5/16" as apposed from viewing from directly above. Without going out to the boat to measure the timing marks, I think my estimate is pretty close on 5 degrees.

[TRBenj]

IIRC, the pointer is closer than 1/4". I dont think the pointer/balancer can be viewed from a full 45 degree range either. Even if that is the case, having the timing off by 5 degrees would not cause the boat to degrade in performance to the tune of almost 1500rpm.