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3.5 CCk Onan generator

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Hi all, I have a 3.5 Kw military CCK Onan generator and have heard it might be 24v for starting, as it has never been good on only 12 v you have to pulse the start button to rock the engine past compression the it will turn over and start. Suggestions please ?

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I know nothing about these generators, but it might also have a decompression lever somewhere to aid in starting.

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2 hours ago, Starfire said:

I know nothing about these generators, but it might also have a decompression lever somewhere to aid in starting.

The Onan 3.5 Kva geny is a 2 cylinder side valve and of low compression.. no decompressor needed. Despite working on scores of these 30+ years ago I can’t remember if they are 12 or 24 volt start but I feel sure there is a data plate on them with Details, output, etc.

 

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ok it seems to be marked "12volts Bat" but on a good truck battery it refuses to turn over in one continuous motion and the rotation is very slow !!!

Any suggestions on how and what to test if a winding is down, or any other thoughts ?

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 Just a quick clean and check all of the electrical conections, Carefully put your hand near or on the starter motor to see if there is any heat comming through the casing. If there is that could be an indication of an internal problem

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1 hour ago, john1950 said:

 Just a quick clean and check all of the electrical conections, Carefully put your hand near or on the starter motor to see if there is any heat comming through the casing. If there is that could be an indication of an internal problem

As I recall it uses the generator as a starter, there is no separate motor

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Same start line looking for an electrical fault. Is the generator brush type or slip ring,are the brushes in good order, is the switch gear using the correct field coils? Be carefull with the internal dust as period generators and electric motors used asbestos wrapping on the internal wiring.

Edited by john1950
addition

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Thanks guys for the input.  I think I have sorted out the bad starting, discovered that of the 4 brushes on the starter side one of the brush connections to the case of the generator was very loose looks like its been like it for years, probably why I have always had problems starting it. So having cleaned and copper slipped it and tightened up good and tight, it seems to start fine but I can't get the fuel pump to prime so engine keeps petering out, then won't start till you tip a bit of fuel down the carb then it runs for a few seconds. Suspect I will need a fuel pump diaphragm, will look tomorrow.

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More of an update fuel pump issues, diaphragm is ok one of the valves in the pump stuck open due to the rubber seal disc has swollen a bit and jamming on cage which retains the spring, trimmed the disc down a bit reassembled and all good.

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