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Onan Generators

ONAN JB 7.5 new life


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  #71  
Old 03-20-2017, 08:12:27 PM
fisherman81654 fisherman81654 is offline
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Default Re: ONAN JB 7.5 new life

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Originally Posted by len k View Post
Good sign that pushing centrifugal switch points closed makes relay in control box click, means at least that part of circuit is working. Next test would be to use a test light between frame and +12V lead of spark coil and confirm that you have power at coil when you manually close the centrifugal switch. From schematic looks like it should do that even if engine is not running and you don't touch start/stop switch.

I haven't had to take my centrifugal switch apart. But I'm guessing some weights spin and somehow push a rod outward to close the centrifugal points. IF engine is coming up to speed that switch trips at ( ~ 900rpm) and rod doesn't move then sounds like the rod is sticking. Also check gap.

If gen is making AC, 900 rpm corresponds to 30 hz. Most people here use a $22 kill-a-watt meter to measure hz, which is directly proportional to rpm.

I'ld say read the manual for details on how centrifugal switch works, I haven't.
I tore it down today and the problem was someone had bent the pin that the two springs attach to. They bent it in such a way that it would had to have MORE rpms to close the circuit. I bent it back straight and checked that each spring was about a inch and half in length, Aligned the two gears. put it back together and it now starts great. The rod was fine, set the gap to .020
It did have two waits that open up and there was no play to the mount.

Getting back to the fuel pump leaking oil,JB weld did not stop the oil leak for very long. I may take it off and look into some other way of fixing the leak.
I would like to keep it as original as possible. Got a cheap electric pump off eBay, hate to put that on it, we will see. Thanks everyone!
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  #72  
Old 03-20-2017, 08:44:57 PM
JohnnyC JohnnyC is offline
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Default Re: ONAN JB 7.5 new life

Glad to hear you got the centrifugal switch problem figured out. You are now one of the resident smart guys for centrifugal switch problems.

JohnnyC
New Jersey
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  #73  
Old 03-21-2017, 07:10:49 PM
fisherman81654 fisherman81654 is offline
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Default Re: ONAN JB 7.5 new life

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Glad to hear you got the centrifugal switch problem figured out. You are now one of the resident smart guys for centrifugal switch problems.

JohnnyC
New Jersey
That's funny. But I'll go with that
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  #74  
Old 03-22-2017, 05:28:18 PM
fisherman81654 fisherman81654 is offline
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Default Re: ONAN JB 7.5 new life

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Originally Posted by fisherman81654 View Post
I tore it down today and the problem was someone had bent the pin that the two springs attach to. They bent it in such a way that it would had to have MORE rpms to close the circuit. I bent it back straight and checked that each spring was about a inch and half in length, Aligned the two gears. put it back together and it now starts great. The rod was fine, set the gap to .020
It did have two waits that open up and there was no play to the mount.

Getting back to the fuel pump leaking oil,JB weld did not stop the oil leak for very long. I may take it off and look into some other way of fixing the leak.
I would like to keep it as original as possible. Got a cheap electric pump off eBay, hate to put that on it, we will see. Thanks everyone!
UPDATE
I took the fuel pump off again today and used a panel cut off tool to clean of the JB weld, cleaned it up with some lacquer thinner and used a different version of JB weld. So far so good.
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