cstroh
I have a Generac Guardian 5744 20 kw generator (roughly 3 months old with less than 8 hours run time) On initial installation, the unit required 11 seconds of cranking to start to excercise after sitting idle for 1 week. I thought that was long. This has now increased to 2 cycles in excess of 20 seconds. Unit appears to run fine once started. I live in Houston Texas so cold temperature is not an issue. The fuel is natural gas and fuel pressure to the fuel solenoid checks out at the required 8" WC. I Changed plugs with no improvement. Also confirmed choke operation. From reading other threads, this is not an uncommon problem. I suspect the fuel regulator. It is not externally adjustable. It has one piped input from the fuel solenoid and two flexible outputs to the air box. It might be possible to alter settings internally but I would like to get as much info on the regulator as possible before trying any changes. Is there possibly a cross section or specification sheet for this new fuel regulator? Generac so far has not provided much after repeated inquiries.
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Scotty306134
The regulator may be sticking... try tapping it while cranking
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cstroh
Scotty306134;7812 wrote:
The regulator may be sticking... try tapping it while cranking


Thanks, I will try that.
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ohmslaw
I would check the valve clearances also.
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cstroh
ohmslaw;7816 wrote:
I would check the valve clearances also.


Thanks, I will do that.
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cstroh
Scotty306134;7812 wrote:
The regulator may be sticking... try tapping it while cranking


The suggestion that the regulator might be sticking was a good one but unforturnately the tapping on it during cranking had no effect. Maybe I did not hit it hard enough. Thanks for the suggestion.
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cstroh
Does anyone know the hole sizes in the air box venturi's that go to the fuel regulator. Could some have gotten plugged?
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Gman1
try gapping the plugs very very close. I have seen it work often. When I say very very close, I mean it.
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Scotty306134
cstroh;7851 wrote:
Does anyone know the hole sizes in the air box venturi's that go to the fuel regulator. Could some have gotten plugged?


It's not likely both venturis would be plugged. If only one was plugged the other cylinder would fire normally. If it were mine I'd disconnect the two outlet flex lines at the regulator and connect two hoses to run outside the housing into seperate bottles of water. Disconnect the Generac wireing to the fuel solonid and connect the solonoid to an outside 12 volt source. When connecting the solonoid You should hear it operate. After checking for operation noise You should be getting gas out of the hoses You ran outside (watch the bubbles). Be aware not to have any sparking near where the gas is being expelled!!!! If there's no noise the solonoid wireing is open or the plunger is sticking. If no gas the regulator is defective. Again .. NO SPARKS near where the gas is being expelled!
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Zapme
cstroh, Those little dirt dobbers we have in the south can screw up a lot of things. Bottom line, the fuel is not getting to the generator in time for it to fire off and dirt dobbers can clog up the smallest holes.
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cstroh
Scotty306134;7874 wrote:
It's not likely both venturis would be plugged. If only one was plugged the other cylinder would fire normally. If it were mine I'd disconnect the two outlet flex lines at the regulator and connect two hoses to run outside the housing into seperate bottles of water. Disconnect the Generac wireing to the fuel solonid and connect the solonoid to an outside 12 volt source. When connecting the solonoid You should hear it operate. After checking for operation noise You should be getting gas out of the hoses You ran outside (watch the bubbles). Be aware not to have any sparking near where the gas is being expelled!!!! If there's no noise the solonoid wireing is open or the plunger is sticking. If no gas the regulator is defective. Again .. NO SPARKS near where the gas is being expelled!


This raises a very good question. I have done this test and no gas comes from the regulator. I suspected this to be as it should be since without any vacuum applied to the discharge lines there is no gas demand. Have you found this to be otherwise?
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Scotty306134
This raises a very good question. I have done this test and no gas comes from the regulator. I suspected this to be as it should be since without any vacuum applied to the discharge lines there is no gas demand. Have you found this to be otherwise?[/QUOTE

Yes Cstroh You are correct. Without vacuum there shouldn't be any fuel delivered. I'm sorry, but I hadn't thought about that! My lack of experience is showing up! I have a 15KW generator I just installed and switched to LP from NG. I'm looking at the parts breakdown for the regulator in my manual. I'm assuming the basic design and operation of our regulators is similar. Mine has three hoses from the engine to the regulator. Two of equal size(1/2" ID) and one smaller. When I switched from NG to LP I had to install a small brass jet into the threaded hole where the smaller hose attaches to the regulator. Im suspicious that the LP gas jet may be screwed into Your port or something similar. I believe it cuts down on the amt of vacuum reaching the regulator and would cause Your problem. I hope I'm able to help. Most of my experience is with gasoline and diesel engines. Scotty
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