M impulse coupler

billy boy2 · May 10, 2013

When I have the engine with #1 TDC and the Rotor pointing at #1, then turn the mag opposite the direction of its' normal rotation should I hear the impulse coupler click? That's what I've read, but I hear nothing. Do I need it with electric starter?

Bob · May 10, 2013

Yes, it should trip unless it already had tripped at the point you started. If you hand crank it with the mag GROUNDED out so you don't get a broken arm, do you here it snapping twice per crank revolution?

Yon NEED it even with a starter 'cuz it effectively retards the spark at cranking by 20-some º to avoid kick-back that can break the nose cone off of the starter.

billy boy2 · May 10, 2013

Well this one is about 2 days away from the scrap yard. I Pulled the mag and turned it by hand and I'm hearing it and seeing the rotor "jump" each time. When turning the drive by hand, I feel it "load up" then shoot on around. Put it back together and retimed, checked spark. Had good spark, tried it a time or 2, then no spark. If it doesn't run the next time or 2 I mess with it, I know it's worth $.11 per pound. I'll be taking a huge loss, but getting rid of some grief.

pete 23 · May 10, 2013

If the impulse is good it take a good effort to turn by hand and makes a strong snap. Most of them are plum worn out but some just need a little bit of tweeking. The ends of the weights contact a pin, and that pin wears flat. You can knock the pin out and reinstall in a different positon. Also, the end of the weight need to be flat and square. I often just grind them a bit to reshape them. But, if the pivot for the weight is worn bad you are probably out of luck. Springs get wear and or break also. You should hear a pronounced loud snap when turning engine by hand and it should do it just a hair after top dead center because that piston does not care which way the crankshaft is turning if it decided to fire.

Paul from MI · May 10, 2013

The impulse will only work turning the mag in its normal rotation direction. When turned backwards, it will NOT work.

billy boy2 · May 10, 2013

The impulse looked good by your descriptions. Very strong. I had to put the double possum grip on it to turn it :lol: The pin looked round too . I also noticed you can't turn it backward. I'm guessing the weights stick out and snag on the pin. I thought I had a propane problem, but in the back of my mind I was thinking stuck points. I took it off and apart and checked the impulse and seemed good. Checked the points and they were barely opening and pretty corroded. I cleaned them and put it all back together and it fired a couple of times, then nothing. Now the points have continuity to ground whether opened or closed,but only if the coil in the mag is hooked up. I'll start from there in the morning.

billy boy2 · May 11, 2013

She runs at last

I stuck a resistor and 12 volt coil on this morning and she fired up like she should. Motor sounds good, oil pressure good

Now to test tune and tinker. I'm getting anxious just to ride it down the road once.

M impulse coupler

billy boy2

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Bob

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pete 23

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Paul from MI

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billy boy2

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