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Onan 7.5 kw Ignition Problem


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  #11  
Old 03-14-2018, 01:13:36 PM
Leon N. Leon N. is offline
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Default Re: Onan 7.5 kw Ignition Problem

Sorry, I my typing is bad. What I mean to say is follow the "engine stopped" ignition timing procedure as described in 967-500., top of page 30. "Plant Stopped" as 9nan puts it.
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  #12  
Old 03-16-2018, 12:34:09 PM
Steelhant Steelhant is offline
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Default Re: Onan 7.5 kw Ignition Problem

I ordered point saver, but in the meantime may be another winter storm coming .. I replaced the points...running perfect again. I will let you know how I make out when I get the other parts.

Thanks,
Chuck
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  #13  
Old 03-16-2018, 02:46:08 PM
Max Thompson Max Thompson is offline
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Default Re: Onan 7.5 kw Ignition Problem

Do you have the cover for the start disconnect / points mounting plate? Looks kind of dirty and oily in there. Also check to be sure there is no oil escaping around the points plunger.
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Old 03-16-2018, 05:03:04 PM
Leon N. Leon N. is offline
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Default Re: Onan 7.5 kw Ignition Problem

I have that slight oil leak Max descibes. So I leave the cover off in order to keep the points dry
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Old 03-16-2018, 08:55:27 PM
Max Thompson Max Thompson is offline
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Default Re: Onan 7.5 kw Ignition Problem

Quote:
Originally Posted by Leon N. View Post
I have that slight oil leak Max descibes. So I leave the cover off in order to keep the points dry
A $3 diaphragm will fix that. It can be replaced without removing the base from the set, though you will have to remove the points. The oil will draw dirt, especially with the cover left off.

A "puller" made from a small "pocket screw driver" works great. Heat the screw driver up and bend about a 1/4" 90 in the end. This will remove the retaining disk.
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  #16  
Old 03-16-2018, 10:05:08 PM
Leon N. Leon N. is offline
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Default Re: Onan 7.5 kw Ignition Problem

Max, thanks for the information. I will take another look to see just how bad it is. I recall maybe a year ago when I removed the cover, there was some oil pooled inside and the condenser was wet. Points remained dry and no sparking. Will add this to a couple of other things I should look into. That is try out the old timing light I obtained through the help of LenK and try to eliminate the 1500 watt govenor hunting. Think I will wait till the weather warms up a bit and the series of storms passes.

BTW! What is a good source for that JB points diaphragm and retainer disk?
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Old 03-17-2018, 10:13:53 AM
Steelhant Steelhant is offline
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Default Re: Onan 7.5 kw Ignition Problem

I was waiting on the point saver, they were talking about another storm, just wanted to see if I could get it running again, maybe some brake cleaner ! there really wasn't any oil inside the cover, just some residue. When the weather breaks I will clean it. Really is a great generator even if it's 40 years old. I looked at new ones, they all seem to run at 3600 rpm...and not sure what ones are good. Built like a tank..purrs at 1800 rpm and can barley hear it.


Thank you,
Chuck
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  #18  
Old 03-17-2018, 10:28:27 AM
Leon N. Leon N. is offline
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Default Re: Onan 7.5 kw Ignition Problem

Chuck, I am a long time user of the Onan 7500 watt magneciter equipped JB. If I were you I would opt for or stick with the 1800 RPM units. The point saver design I guess is trouble free and works. However, I have stayed with the Onan genuine ignition point/condenser design and have never had a problem. Yes, I changed the points and the condenser just once in 40+ years of use.

One thing you do not hear much about WRT the conventional ignition point design from the 60's is that if your 12 volt battery charging system goes haywire and the voltage builds up too high, it can damage and/or cause the points to deteriorate sooner rather than later.
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Old 03-17-2018, 10:43:21 AM
Steelhant Steelhant is offline
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Default Re: Onan 7.5 kw Ignition Problem

Leon I will check the voltage when running, just to see what I have.

Also do you have any issues with it starting in cold weather ? I tried to set up auto start, but many times I had to give it a shot of starting fluid to get it to fire over, so I just start manually and it works for me. I see your live in this crazy weather area too.

Thanks again,
Chuck
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Old 03-17-2018, 12:23:51 PM
Leon N. Leon N. is offline
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Default Re: Onan 7.5 kw Ignition Problem

Chuck. Yes, I have had issues in the past starting in cold weather, and I mean zero weather, many years ago. The big thing for me early on was oil viscosity because Onan told me 90% of the wear occurs in the first 15 minutes of operation. I switched to 5 W 20 full synthetic all year round and that issue went away.

Next, I use natural gas so my choke is wired open all,the time. If you are using gasoline, you need to make sure your electrically heated bi-metallic choke mechanism is adjusted and working properly. Using starting fluid is risky and it "could" damage internals. If I were you, refer to the Onan gasoline choke adjustment procedures described in both 967-320 and 967-500. You must note your JB factory build spec to get to the correct adjustments which are ambient temperature dependent, to say the least.

If the gasoline designed choke is set properly, your machine should start quickly because the carburetor bowel is always full and immediately come up to 1800 rpm.
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