Help Installing Magneto Engine Crank Rubber Seal

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2door

2door

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Sep 15, 2008
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wan37 said:
I had a seal bad on a motor that was brand new and I had a friend who had a extra seal I think it was a china one so I used some grease around the outer part and the inner part.I pushed it in and it went pretty far and it's not flush is that to far in.I started it up and still revving higher than I like.I wonder if it is still leaking air don't see any fuel mixture coming out like before.I would like to know how to test it.I can spray something around it but it idles so high I'm kinda afraid to keep it running,but it's not running all way open I can rev it higher with throttle.So should I chance and let it run so I can spray something around it?
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Is your throttle working correctly? Is the slide (barrel) in the carb moving smoothly up and down? Is the cable binding? Have you tried the idle speed screw? In is faster, out is slower. Have you looked for air (vacuum) leaks other places like the carburetor to intake manifold and the manifold gasket where it attaches to the cylinder?

Tom
 
W

wan37

Member
May 29, 2011
354
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Illinois
2door I have resealed the intake with seal all and new gasket and the carb with o ring and seal all and I got some throttle response the barrel slide is in right.Idle screw does nothing at all in so far or out all the way.I'm think I'm too much of chicken to let it run at high idle to spray stuff to find the leak because it a new engine.It's not idling all the way wide open because I can rev it higher with throttle.
 
Al.Fisherman

Al.Fisherman

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Sep 9, 2009
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Calera, Alabama
wan37 said:
I had a seal bad on a motor that was brand new and I had a friend who had a extra seal I think it was a china one so I used some grease around the outer part and the inner part.I pushed it in and it went pretty far and it's not flush is that to far in.I started it up and still revving higher than I like.I wonder if it is still leaking air don't see any fuel mixture coming out like before.I would like to know how to test it.I can spray something around it but it idles so high I'm kinda afraid to keep it running,but it's not running all way open I can rev it higher with throttle.So should I chance and let it run so I can spray something around it?
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Both seals (crankshaft) are the same OD and ID, but the thickness on the right (7.5mm) and left (3.8mm) side are different.
 
W

wan37

Member
May 29, 2011
354
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Illinois
I used the 3.8mm one on the left side but it went in pretty far so I really think the bigger one would work.I don't really know for sure.I started it and its still running bad with the 3.8mm so I pull the magnet and the magneto and it looks fine.I'm sure its still leaking air .What kinda stuff can I use to spray when its running to see if it's leaking?
 
Al.Fisherman

Al.Fisherman

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Sep 9, 2009
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Calera, Alabama
wan37 said:
I used the 3.8mm one on the left side but it went in pretty far so I really think the bigger one would work.I don't really know for sure.I started it and its still running bad with the 3.8mm so I pull the magnet and the magneto and it looks fine.I'm sure its still leaking air .What kinda stuff can I use to spray when its running to see if it's leaking?
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When replacing a seal, lube needs to be used on the inner seal, and I usually use a sealer like Aviation Gasket/Indian Head sealer, around the outside edge.
 
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birdmannn101

birdmannn101

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Oct 23, 2011
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Indianapolis, IN
Wan37,

I put my 3rd seal in the engine with a press tool and it needs to be flush with the engine casing because there is a possibility that the magneto will rub on the new seal, heat it up and cause it to leak.

You can always check to see if it is leaking by taking the plate off the engine and looking to see if it is still leaking.

The grease on the outside and inside of the seal is a good idea. I have never seen one that just slipped right in without tapping it with a seal press.

Dan
 
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wan37

Member
May 29, 2011
354
4
18
Illinois
well I lube it with grease and it went right on in nice and straight but it went in farther then flush,so put it back to gather started it and ran it for a bit.I started it again and let it run for a while then choked it and it died just like it should.I'm happy with it right now.
 
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biknut

biknut

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Sep 28, 2010
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You can easily tell is a seal is leaking by all the oil blowing out, where it's not supposed to be.
 
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