A question about point gap and timing mark

[joecb]

So, I have been setting up breaker points using the feeler gage for the past 50 years and never (I thought) had an issue. So, I just took a freshly tuned 9.5 Evenrude to a friend to tank test. He says, lets put the timing light on it to see how well the points are set. Well, one cyl was right on the mark, the other way too early to the mark. We fiddled with the “bad” point setting till I had to run, and it seemed that the very slightest, almost imperviable difference with the feeler gage had a significant result with the timing light. Now, I know how to use feelers, been doing it for many years… the question is just how much effect on timing does a .001 or two make when setting points? and is it really that critical to engine performance?

Joe B

[crosbyman]

the gap is important doing it manually  with the high point of the lobe  at TDC ….but points openning at TDC  using this method  is perfection.

http://www.youtube.com/watch?v=ga1Cjymj6ms&feature=youtu.be

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joecb

[joecb]

Thanks for that… I had forgotten about that technique for point setting. I just went through the suggested procedure, and all seems good. Time to go back to the test tank.

Joe B

[h20lew]

A magneto buzz box is even better – something similar to the one in this link:

https://www.aircraftspruce.com/catalog/topages/synchronizer_12-16903.php

The benefit with this tool is you do not need to disconnect the coil wire from the points.

[crosbyman]

looks ok but…$$$$ for a few  jobs. and actually VOM can go for 15-20$ these days.   a LED and wires pennies !

I also use  an old Telco VOM  a KS14150 with a 1 ohm scale !!   so sentive the needle dips when points open up.:-)

Vinitage Bell System KS-14510-L1 Multimeter Volt Ohm Meter | eBay

all depends  on the budget I guess

 

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frankr

[RICHARD A. WHITE]

Remember, they make a tool to remove this issue…. of point setting…with the high point of the cam point setting process, how can you “know” you are exactly where you need to be and then how do you “know” you rotate the crank exactly 180 degrees?

 

just sayin..lol

 

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

[fleetwin]

OK, well I surely understand the procedure and that it can make a difference.  The problem here is that we are usually dealing with some “slop”/tolerances, so what we work so hard to achieve is rarely achieved.  In other words, you use the tool, set up everything as meticulously as possible, only to be disappointed when we use the timing light to check our work.   New points should be set to the first timing mark (a little advanced) to compensate for initial rubbing block wear.  Used points should be set in the middle of the two marks.   .001”

difference in feeler gage settings is not going to make much, if any difference.

[labrador-guy]

I am coming late to the party here but here I go.  I learned a long time ago to use a continuity light and a dial indicator to set timing.  Two cylinder engine set one set of points at spec setting.  Hook up continuity light to points wire on that cylinder, ignition switch on, dial indicator in spark plug hole turn motor to top dead center, zero dial.  Slowly turn motor opposite of it’s normal rotation  watch light.  When points close the light will brighten up.  Read  and note the dial when the light brightens.   Move dial indicator to the other cylinder, set TDC on that side move continuity light to the other point wire.  Set the points on second cylinder to match the first.  Remember  “wider points make more advance, narrow points to retard timing”.  I taught three snowmobile shops how to set timing many moons ago.  I learned at our distributor maintenance seminar.  I made my own  continuity light out of a big flashlight and I still have it.  I check outboards with this arrangement.  Gotta make sure advance stays in the same spot for both cylinders.

whew dale

[crosbyman]

see pict.

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[rudderless]

Upper bearing clearance can mess with one also.  One can set it static and wonder why when running using a light its off the mark..

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