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post #1 of 14 Old 04-18-2015, 09:33 AM Thread Starter
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Magneto couplers

Do all the different magnetos use the same phenolic coupler? There is a guy at my church that bought a older L about a year ago, and wants to get it running this year to mow his grass. He pretty much knows nothing about them, and I know just a little more than nothing.

He could not get it started, and I told him to make sure the magneto made a "click" when he turned the engine by hand, and how it had a spring loaded mechanism inside to make it fire at low speeds. He got a guy to help him take it apart and said his magneto did not have the centrifugal mechanism inside, but they did find the points corroded, and they fixed that. He goes to put it together and finds he has lost the phenolic coupler for the magneto. He asked me if I had any parts and if I may have one.

Both my L's have a Wico magneto that clicks. And both of mine have what looks like a round coupler made of a brown material and it looks like it has a thin slot on both sides, perpendicular to each other. Of course I need both my couplers, no spares, but was wondering if I found him one, would they all look like mine.

I was thinking of asking him if he had access to a machine shop, I could take one of mine off and they should be able to easily make one out of nylon or some sort of phenolic. I even thought a wooden dowel rod. But I just saw the post on here where the guy just bought 6 gravelys, and said something about parts. So I was thinking of Pm'ing him about a coupler if they all were the same. I haven't been to the church guy's house to see if a type like mine would fit or not, but thought you guys probably would know.
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post #2 of 14 Old 04-18-2015, 10:19 AM
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Re: Magneto couplers

They are all the same from the mid fifties on. I believe the early, early ones were a tad narrower, but the adjustable block can be moved closer to the magneto if a narrow one is used.

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post #3 of 14 Old 04-18-2015, 11:27 PM Thread Starter
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Re: Magneto couplers

Ok, thanks. I will talk to him tomorrow and see what he wants to do.
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post #4 of 14 Old 04-19-2015, 12:27 AM
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Re: Magneto couplers

Hello, just let me know...also send me a pic of yours if you can and or year of his machine...I will send you one free...just pay a few bucks for shipping...

Gary

Gary r. voigt

Gary's gravely garage

remember, those who preserve the past, also serve the future
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post #5 of 14 Old 04-19-2015, 12:26 PM
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Re: Magneto couplers

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Originally Posted by franklin2 View Post



He could not get it started, and I told him to make sure the magneto made a "click" when he turned the engine by hand, and how it had a spring loaded mechanism inside to make it fire at low speeds. He got a guy to help him take it apart and said his magneto did not have the centrifugal mechanism inside, but they did find the points corroded, and they fixed that. He goes to put it together and finds he has lost the phenolic coupler for the magneto. He asked me if I had any parts and if I may have one.

I'm a bit concerned with the above statement that indicates that the impulse mechanism is missing and or inoperative, without that you may find it very hard to get a strong enough spark to fire off the engine. The impulse mechanism winds up and releases at a specific point, when it "snaps" the roster inside the magneto is accelerated to a speed the generates the necessary voltage for ignition. Sadly your friend will need to find the missing parts and or a new magneto.

Good luck!
Corey
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post #6 of 14 Old 04-19-2015, 12:34 PM
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Re: Magneto couplers

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Originally Posted by cmeyers77 View Post
I'm a bit concerned with the above statement that indicates that the impulse mechanism is missing and or inoperative, without that you may find it very hard to get a strong enough spark to fire off the engine. The impulse mechanism winds up and releases at a specific point, when it "snaps" the roster inside the magneto is accelerated to a speed the generates the necessary voltage for ignition. Sadly your friend will need to find the missing parts and or a new magneto.

Good luck!
Corey
I bet they didn't have the back cover off just the front where the points are I know it won't work with out it

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post #7 of 14 Old 04-19-2015, 12:48 PM
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Re: Magneto couplers

You are right, it definitely won't work without that. The spring is likely broken.
What engine is it on? I only recall seeing external mags with a gear that engaged with the camshaft, no direct couplings.
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post #8 of 14 Old 04-19-2015, 03:39 PM Thread Starter
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Re: Magneto couplers

So you guys are saying all the different mags had the wind-up spring? I told him specifically to look for it and to see if it worked. He said it didn't have it, so I thought maybe the different manufacturers had different designs.

I talked to him this morning, he said if I can get the coupler from Gary to go ahead and do it. If it still won't start, I might have to go over there and we might be needing more parts.

I haven't been to his house before, but he keeps telling me he has this bank he wants to mow. I asked him if he had dual wheel adapters and he said no. I have my doubts it's going to work for him, but hopefully we can step in and guide him through. I know my L was transformed from a dud to a mean machine when the dual wheel adapters were installed.
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post #9 of 14 Old 04-19-2015, 05:18 PM
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Re: Magneto couplers

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You are right, it definitely won't work without that. The spring is likely broken.

What engine is it on? I only recall seeing external mags with a gear that engaged with the camshaft, no direct couplings.

All model L Gravely's had an external Magneto driven off the exhaust camshaft, the mag was coupled to the cam shaft via a round phenolic spacer, each end had a slot 180 out form the other. One end of the spacer fit on to the magneto, the other onto the camshaft. On the camshaft end there was part that would engage that round phenolic spacer, there was a means to adjust that part to specified clearance to the magneto.

Every magneto that gravely used on the L was equipped with an impulse mechanism. The impulse was only active at low rpm, which would in turn wind up a spring attached to the rotor, when the spring let loose it spun the rotor at a much higher speed then the engine, this quick Snap! action would generate the necessary spark for ignition. If the Magneto Impulse is inoperative it is highly unlikely that enough spark if any would be generated for ignition.
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post #10 of 14 Old 04-19-2015, 05:34 PM
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Magneto couplers

Notice the rectangular block on the exhaust camshaft (Magneto Coupling) that is clamped to the camshaft and will drive the magneto via the phenolic spacer.

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post #11 of 14 Old 04-19-2015, 05:35 PM
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Magneto couplers

Older mag and drive, notice that the phenolic spacer (Magneto Fiber Float Member) is the same

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Last edited by cmeyers77; 04-19-2015 at 06:16 PM.
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post #12 of 14 Old 04-19-2015, 06:04 PM Thread Starter
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Re: Magneto couplers

The news that it should have the wind-up mechanism is not good. I need to quiz him further about that.

I have been into one of mine before, it had a problem of being intermittent. When it clicks it's very loud and noticeable, and I noticed mine didn't sometimes. I took mine apart and found the arm to be slightly magnetic and it would stick to the mechanism, making it not work. I ended up putting a little blob of epoxy on the arm where it made contact, and that kept it from sticking to the other piece.
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post #13 of 14 Old 04-19-2015, 06:15 PM
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Re: Magneto couplers

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Originally Posted by franklin2 View Post
The news that it should have the wind-up mechanism is not good. I need to quiz him further about that.



I have been into one of mine before, it had a problem of being intermittent. When it clicks it's very loud and noticeable, and I noticed mine didn't sometimes. I took mine apart and found the arm to be slightly magnetic and it would stick to the mechanism, making it not work. I ended up putting a little blob of epoxy on the arm where it made contact, and that kept it from sticking to the other piece.

It's not uncommon for the impulse paws to become magnetic, this of corse will cause intermittent impulse engagement.
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post #14 of 14 Old 04-20-2015, 06:20 PM Thread Starter
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Re: Magneto couplers

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Hello, just let me know...also send me a pic of yours if you can and or year of his machine...I will send you one free...just pay a few bucks for shipping...

Gary
Gary, I sent you a PM. I would like to take you up on your offer.
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