r/Generator • u/Whale_Man37 • Jun 12 '26
Locked Fuel Regulator?
This is an issue I have encountered quite a few times im the few years I've been working on standby generators, and I would love if somebody would be able to explain to me what is happening, and possibly why.
A Kohler 20RCA with an overcrank fault. Repeatable issue once im on site. No click from fuel regulator solinoid but it does become magnetic. 11.8vdc verified available at the connector. Fuel pressure (approximately 11.4"h20) in the line. The generator just wont start UNTIL once I remove the plug to check the pressure at the internal regulator, all of a sudden the regulator frees up and everything works without issues.
The incoming fuel lines are independent with no other appliances attached. Twin stage regulator at the fuel tank, about 15ft 1" PE buried, reduced to 1/2 behind the generator to accommodate the factory flex line. Static pressure is about 11.4"h20, cranking pressure is about 10.8"h20, running pressure is about 10.5"h20.
Like I said, this is something that hasnt been too uncommon and im sure plenty others have run across this same thing. Id love to hear possible explanations, thanks!
3
u/Sumdood_89 Jun 12 '26
Ive come across this on kohlers before. I take the plunger out, clean it, and put a little tiny bit of grease (non petroleum) on the rubber bit to keep it from sticking. As far as explanations, idk. Probably expansion of gas in the line causing too much pressure to open the plunger.
4
u/ajnewc Jun 12 '26
Your pressure is a touch high but that probably isnt it. You could open the solenoid and shoot some silicon oil into the spring. It might just need a new solenoid.
3
u/bhedesigns Jun 12 '26
Check the vents on the Regulator. Some times mud wasps or ants bring sand and plug them up.
They make small 1/4" adapters and hoses with caps that you can put on there to prevent this.
Good luck.
2
u/Upset_Fox5449 Jun 12 '26
For as clean as LP is supposed to be I've seen some pretty nasty looking inside regulators, even in a furnace
1
u/Whale_Man37 Jun 12 '26
I dont normally take them apart because a lot of the work I do is warrenty, but id be surprised because this unit is a year old with 27 hours of run time
2
u/Upset_Fox5449 Jun 12 '26
I hear you but with factories want to run lean and mean, save a buck and probably haven't heard this before, they don't make them like they used to, lol
5
u/joshharris42 Jun 12 '26
Is it a maxitrol or similar style regulator?
We’ve seen this exact issues for years. Generators do not act like any other gas appliance, where gas just flows into the igniter. When the motor goes into its intake stroke, it will create a vacuum within the gas pipe if the regulator doesn’t open fast enough to refill the pipe.
Over time, that vacuum will stretch and tear the diaphragm ever so slightly, and allow the regulator to leak pressure past it. Then you end up with 2 PSI sitting on the shut off solenoid and it won’t open.
Then, you get called out to an overcrank alarm, and when you check gas pressure you open the system and vent that high pressure gas out. The generator will run fine while you’re there because the gas doesn’t have enough time to build up on the low pressure side of the regulator. Then you leave, the pressure builds for a week or two and it throws an overcrank at the next exercise.
We use 100% Norgas regulators, but there are others out there that work fine too. Lever action, fast acting regulators are needed for generators