Point Adjustment – 1965 Big Twin

[aziegner]

I installed new points and condensers.
I’d like to know how to set/adjust the points. There are 2 marks on the magneto plate. Do they need to be in a certain position or aligned with something? Please see attached picture.
I plan to get the manual for "this old motor" but am wondering if anyone can help so I can get on the water.
1965 40hp Evinrude Big Twin
Adam
Newfane, VT 05345

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[dave-bernard]

bring the cam up to TOP and set the points. if it does not have top then watch the points to open to the fullest and set. hope I explained it good enough.

[frankr]

There are two ways to set the points. One is with a feeler gauge (.020" at widest opening). Second method is with a timing fixture. That is what the marks on the mag plate are for.

But if you are speaking of the two marks on the brass cam plate, those are for synchronizing the spark with the opening of the carburetor throttle shaft. With the two marks aligned with the pointer (nearby in your picture), the carb should just barely be about to start opening.

free upload image

[wick83]

What Frank said

[garry-in-michigan]

The high point on the cam generally corresponds to the keyway. With the rubbing block of the breaker at that point, the gap is set at 0.020". The double raised lines on the outside rim of the breaker base is used IF you have the factory timing fixture. The results are the same. The two stamped lines you see on the throttle cam are for throttle syncronazation. As the magneto advances, it picks up the roller on the carburetor throttle arm. The throttle plate (AKA butterfly valve) should just start to open when the roller is between those two lines. It is adjustable by loosening the port screw under the throttle cam. (Port its the left side of the boat when facing the bow [front]) That would be the right when facing the motor.
top of magneto

bottom of magneto

Timing tool

. . . . . . . 😀

[Anonymous]

quote betty ann bernardd:

bring the cam up to TOP and set the points. if it does not have top then watch the points to open to the fullest and set. hope I explained it good enough.

Question: does the word TOP in any way indicate the "high" point on the cam?? I’ve always thought it just meant which side of the cam faces up!

[frankr]

"Top" indeed does mean "this side up". Keyway is a better indicator of high spot.
With all due respect to Garry, (and I know he knows this) the brass cam marks are to be aligned with the POINTER on the Big Twin series. But yes with the roller on smaller motors. Anything to confuse a feller.

[wick83]

Top does mean the top side of the camp but if you take a note at where the keyway rests in the can generally it’s dead center of where it says top

[RICHARD A. WHITE]

It is just downright flipping insane the difference of using feeler gages vs the timer tool. Yes you can get it close with the feelers gages but SPOT on makes all the difference in the world. I really need to get a tach to see just how slow you can idle down to…

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[frankr]

OK, I just did some measurements on a cam. Anywhere between the "o" in "TOP" and the center of the key could qualify as the high spot. The "p" in top is sort of iffy, as is the trailing edge of the key. Aw heck, nobody gets them that accurate with a feeler gauge anyway. If you want to get it right, use a timing fixture. Easy for me to say, I make ’em.

picture uploading

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