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Discussion Starter #1 (Edited)
I have a, 7 KW standby home generator, runs on propane from on-site underground tank. Been in service for 6-7 years. Engine has been trouble free. ( Can't say that about the electronics, though, and I still won't buy another Generac when this one goes ). All I have done to the engine is routine oil changes, battery maintenance, and a new spark plug 2 years ago. I check the air cleaner, still looks real clean.

The Problem: The engine is subject to minor speed variations. It's not bad, I think it would stand up to a power outage. But you hear the rpms vary a little bit. It starts easily during its routine exercise periods once a week.

Question: Is there something I can check, as the untrained homeowner, that might cause this? It ran perfectly out of the box up until this fall. I hate to call a service guy as they all basically suck in this area, and screw you mightily. As usual, thanks in advance.
 

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Discussion Starter #3
Either the load adjuster screw...needs adjusting ...or the regulator may need replacing
Regulator: This sounds like it involves breaking into the propane supply line. This might be above my skill level
 

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Do you have a barbecue?...just take the hose from the barbecue and unscrew it from the manifold...take the one off the generator and do a switch to check it out
 

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Speed variations can come from a bunch of things. I installed a 20kw generac standby for my uncle a few years back. I am familiar with generac standbys. Speed fluctuations could be

- a failing stepper motor, the planetary gear inside is plastic. Cheap but not difficult to change

- gain, droop, and stability pot adjustments for the stepper need adjustment

- mice nest inside the propane regulator

- valve lash needs adjustment


Thats all I can think of without seeing it. Best to exercise it monthly with about a 20% or more load for about 30 minutes. The exercise timer if you dont have it set to full speed (aka Quiet Exercise) does not eliminate any condensation that collects inside the engine, plus it allows it to get to full operating temp for a good full heat cycle.

Fairly easy stuff to check if you are familiar with the machine. If not, def call a qualified technician.

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Speed variations can come from a bunch of things. I installed a 20kw generac standby for my uncle a few years back. I am familiar with generac standbys. Speed fluctuations could be

- a failing stepper motor, the planetary gear inside is plastic. Cheap but not difficult to change

- gain, droop, and stability pot adjustments for the stepper need adjustment

- mice nest inside the propane regulator

- valve lash needs adjustment


Thats all I can think of without seeing it. Best to exercise it monthly with about a 20% or more load for about 30 minutes. The exercise timer if you dont have it set to full speed (aka Quiet Exercise) does not eliminate any condensation that collects inside the engine, plus it allows it to get to full operating temp for a good full heat cycle.

Fairly easy stuff to check if you are familiar with the machine. If not, def call a qualified technician.

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mice inside propane regulator???... boy you have some serious problems when that happens!!!
plus - every propane regulator I have ever seen was made of metal... perhaps these are special sabre-tooth mice, that are able to chew through that, to get inside.....
 

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mice inside propane regulator???... boy you have some serious problems when that happens!!!

plus - every propane regulator I have ever seen was made of metal... perhaps these are special sabre-tooth mice, that are able to chew through that, to get inside.....

They block the regulator vent I mean choking it. Often you find spiders and their webs inside the regulators that block the flow of gas.

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Discussion Starter #10
When it鈥檚 exercising does it have a load on it? Maybe put a decent load like 50% on it & see what it does. I鈥檝e had engines that surge until they鈥檙e under load.
Steddy: on exercise period, it is not under any load. Good call, maybe I should take your suggestion.
 

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Discussion Starter #11
Do you own the tank...or lease it? if you lease it the company may be responsible for it
Mark: I own the tank. If the propane company owns the tank around here, they bend you over for the price per gallon and do not use Vaseline. And seem quite proud of the fact they can screw you, especially Amerigas.
 

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They block the regulator vent I mean choking it. Often you find spiders and their webs inside the regulators that block the flow of gas.

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yea - i kinda knew what you meant - just wanted to inject some humor into the discussion.... I've been trying to trap the sabre-tooth mice that appear to chew through some concrete around the frame of my entrance door in the garage... so I know that species of mice exist - i just didnt realize they also were fond of gas regulators....

the external vent doesnt really have any gas flow. it is the point where atmospheric pressure is present in order to have the regulator actually do it's job and regulate the flow of gas "in relation to ambient atmospheric pressure". There is no actual flow through that vent. So unless the inside is caked with mud etc from wasps building their nests, there is no harm done. Spider webs etc do not affect the regulator function at all. But any mud etc caked in there, can affect the ever-so-slight diaphragm movement in the regulator..... although I doubt it would ever be noticeable.
And certainly, no mice can get into that space because the vent holes are too small.....

cheers!
 
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