Generac 12 KW LP gas hard/no start

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Aociccarelli
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12 kw Generac, lp gas, model 04456 w/ 1,300 hours ( runs as supplement to off grid solar home).
Increasingly hard to start (2-3 crank cycles), now cranking but not starting.
Appeared initially worse w/ cold weather but now problem same warm or cold.
Will start/run if I "prime" it by disconnecting wire to crank relay, manually turn on to allow fuel solenoid to open and fuel to enter carb then reconnect crank relay and start as normal - but even this is getting less reliable .
Initially thought fuel issue- so have replaced LP tank regulator (which was a bit off) and fuel solenoid. Have replaced plugs and readjusted valves (they were only out a bit).
Next step? replace ignition modules? other ideas?
If need to replace ignition modules how difficult to access?. Thanks
Chris
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Can you post a video of it trying to start?
Sometimes hearing what it sounds like is easier for me.

Shoot the video and upload to YouTube and then paste the link here in a reply and it will auto embed into the post.
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Aociccarelli
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Here is link to video -

of course it started when I shot this but this is what it typically sounds like.
I'll post another video next time it fails to start
Thanks
Chris
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The valves do sound healthy so that's good. The next time it won't start, listen carefully for any low-pitched 'thumping' sounds, or small backfires. If you're hearing that, that's normally a sign of bad coils or cracked wires causing issues.

The other thing I would recommend is to gap the plugs a little tight (around .020 or .025) This will help a little bit if you're having weak spark issues.
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Aociccarelli
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Thanks
Have not noted abnormal noises or back fires but will listen more closely
New plugs yesterday are already gapped at .02
Will forward more info/video
Birken Vogt
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The video showed a fairly normal start from my experience. They often stumble and sputter a bit like that. Hopefully you can catch it on video when it really does something.
Aociccarelli
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Generator doing its thing all weekend- sometimes start, sometimes no. Good crank
Video show no start, then I primed it by disconnecting crank relay, then turning on to allow fuel solenoid to open and let fuel in, then reconnect crank relay and then it starts right up
Again this is a random, intermittent thing

Birken Vogt
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I wonder if the gas solenoid is weak or something and the decreased voltage with the starter engaged is causing it to fail to open. A gas pressure gauge installed after the valve would tell the tale, but some of these used the pressure port for a primer or something like I think yours may have.
Aociccarelli
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Your thoughts echo mine - I have replaced fuel solenoid - no change. I guess I will put a voltmeter on the fuel solenoid wire and a pressure gauge on the gas line just before the carburetor and see what it shows
Thanks
Chris
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There is a lower pressure test port as Birken mentioned that is after the fuel solenoid. If you don't see any pressure there, that will tell you if it's not opening.
Generac tech for over 12 years. I'm here to help!
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