FairfaxStu
Gold Member
Cool Beans. If I were you, it would definitely fix the intake bolt. You have come this far and done this much work. You owe it to yourself to do it right.
-Stu
Generac 15KW generator engine tear down
- Thread starter pclausen
- Start date
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Cool Beans. If I were you, it would definitely fix the intake bolt. You have come this far and done this much work. You owe it to yourself to do it right.
-Stu
OP
pclausen
Veteran Member
Figured it was time for an update.
Over the last weekend, I finally got around to taking my 8kw generator out of service and putting in the 15kw unit. Got it all plumbed up to the gas line and wired to the existing transfer switch.
At first it didn't want to start at all. So I helped it along by spraying some engine starter fluid into the intakes. That did it, and it would keep on running, meaning that it was able to sustain running on propane. Tried to start it again from just the propane supply and after 4 tries where it "almost" started it finally did start on its own. But then I was unable to do it again without spraying ether into the intakes again.
After letting it sit overnight, it started off the propane supply after about 10 seconds of crank time. And I let it run for about 10 minutes with no load where I adjusted the governor for a no-load frequency of 63hz as per the manual. Ran nice and smooth. Shut it back down and tried to start it again. No go.
The 8kw generator has always performed flawlessly, so I doubt I got a fuel starvation issue. Sure, the 8kw consumed slightly less fuel, but more at a full load (which I subjected it to a lot), than the 15kw at idle.
So I suspect that I have an issue with the propane fuel regulator and that was likely the culprit that caused the heavy build up on the other engine in the first place. Any ideas on where to start with this? Should I throw in the towel and have a Generac service tech come and look at the regulator?
To recap, this generator has a new engine it it and is hooked up to a LP supply at a different location from where it was taken out of service and had similar start issues. I really think there is something wrong with the fuel regulator being that I'm experiencing similar hard start symptoms with a new gas supply and new engine. The regulator is about the only thing that did not change!
Over the last weekend, I finally got around to taking my 8kw generator out of service and putting in the 15kw unit. Got it all plumbed up to the gas line and wired to the existing transfer switch.
At first it didn't want to start at all. So I helped it along by spraying some engine starter fluid into the intakes. That did it, and it would keep on running, meaning that it was able to sustain running on propane. Tried to start it again from just the propane supply and after 4 tries where it "almost" started it finally did start on its own. But then I was unable to do it again without spraying ether into the intakes again.
After letting it sit overnight, it started off the propane supply after about 10 seconds of crank time. And I let it run for about 10 minutes with no load where I adjusted the governor for a no-load frequency of 63hz as per the manual. Ran nice and smooth. Shut it back down and tried to start it again. No go.
The 8kw generator has always performed flawlessly, so I doubt I got a fuel starvation issue. Sure, the 8kw consumed slightly less fuel, but more at a full load (which I subjected it to a lot), than the 15kw at idle.
So I suspect that I have an issue with the propane fuel regulator and that was likely the culprit that caused the heavy build up on the other engine in the first place. Any ideas on where to start with this? Should I throw in the towel and have a Generac service tech come and look at the regulator?
To recap, this generator has a new engine it it and is hooked up to a LP supply at a different location from where it was taken out of service and had similar start issues. I really think there is something wrong with the fuel regulator being that I'm experiencing similar hard start symptoms with a new gas supply and new engine. The regulator is about the only thing that did not change!
Last edited:
hr3
Veteran Member
2 things to check first is the selector valve set for the type of fuel you are useing ?? second would be is the choke working properly ???
OP
pclausen
Veteran Member
I think the regulator is set for the correct fuel type. Here's the relevant page from the owner's manual:
The small fuel jet shown in Figure 1.4 is not in the regulator housing port, so I'm assuming it was relocated to behind the brass hose fitting during the original installation (LP gas like where it is now). But I'll go ahead and pull the hose and brass fitting to double check that it is there.
On the choke part, how would I check that? I know the governor throttle arm is linked to the underside of the air filter housing. The throttle arm does not move much if any at all between engine not running, cranking and running. I'm guessing that in order for the choke to work, the throttle arm should be moving during this operation?
The small fuel jet shown in Figure 1.4 is not in the regulator housing port, so I'm assuming it was relocated to behind the brass hose fitting during the original installation (LP gas like where it is now). But I'll go ahead and pull the hose and brass fitting to double check that it is there.
On the choke part, how would I check that? I know the governor throttle arm is linked to the underside of the air filter housing. The throttle arm does not move much if any at all between engine not running, cranking and running. I'm guessing that in order for the choke to work, the throttle arm should be moving during this operation?
hr3
Veteran Member
Take off the air cleaner there should be a plate half across the throttle opening,, When you try to start this should close for a short period.. With a gaseous vapor you have to coax the gas in to start,,
How old is this unit anyway ???
How old is this unit anyway ???
daugen
Epic Contributor
this may be far afield, but when I put in my 20kw Generac, I had long conversations with the propane company who would not make the install unless I doubled the size of my tanks. Not enough vapor production for the rated output of the gen.Now you may be connected to a 500# tank and this is irrelevant, but any possibility your current tank may not be big enough? If it is, then your regulator does sound suspicious.
Great post and pics, thanks. As others have said, sure hope I never go through this. I put in Mobil 1 each year with a new filter, and so far, it's done a couple of multi day outages without a hiccup. But when that single big heat pump kicks in, it will flicker the lights even with a 20kw. I think the problem is more the two fridges and a freezer that I likely ought to simply unplug for awhile during the outage. And my backup heat is electric grid, a Redi Killowat dream house.
Great post and pics, thanks. As others have said, sure hope I never go through this. I put in Mobil 1 each year with a new filter, and so far, it's done a couple of multi day outages without a hiccup. But when that single big heat pump kicks in, it will flicker the lights even with a 20kw. I think the problem is more the two fridges and a freezer that I likely ought to simply unplug for awhile during the outage. And my backup heat is electric grid, a Redi Killowat dream house.
OP
pclausen
Veteran Member
hr3, thanks. I'll pop the air cleaner cover and see what the plate across the throttle opening does when engine is cranking. This is a model 4390-2 from 2006.
Daugen, I have a 500 gallon in ground tank that is at 85% right now. The regulator is 7 feet from the generator and plumbed using all 3/4" black iron pipe.
Daugen, I have a 500 gallon in ground tank that is at 85% right now. The regulator is 7 feet from the generator and plumbed using all 3/4" black iron pipe.
OP
pclausen
Veteran Member
Here are a couple of pics of the installed generator. This shows the gas line coming up into the external regulator with black iron pipe running to the generator itself:
Front view showing its older 8kw cousin:
Here's the intake with the air filter removed. I'm not seeing any choke plate. I'm guessing its buried down inside the filter housing somewhere.
Here' s a shot with the engine not running. Note there is no tension on the idle spring (red arrow). The yellow arrow points to the no load idle adjust screw which I had to tighten a lot to get the engine down in rpm to where it would not shut down from engine overspeed.
Today when I cranked the engine, it started after maybe 10 seconds and the throttle arm moved just slightly to bring a little tension on the idle spring, so nowhere near enough movement to allow for a choke to operate.
After letting it run about about 5 minutes (ran very smooth), I shut it down and tried to restart a minute later to no avail. I should mention that I moved the governor assembly from the old engine to this new engine so maybe something is not set up right with it, but I can't really see what else can be adjusted other than the full load adjust screw which is underneath the air filter housing. I don't plan to put a real/full load on this generator until I can get it to start reliably. I wish I had a 15kw dummy load laying around, but I guess my old 10 seer 4ton AC will have to be that load when I get to that point.
Front view showing its older 8kw cousin:
Here's the intake with the air filter removed. I'm not seeing any choke plate. I'm guessing its buried down inside the filter housing somewhere.
Here' s a shot with the engine not running. Note there is no tension on the idle spring (red arrow). The yellow arrow points to the no load idle adjust screw which I had to tighten a lot to get the engine down in rpm to where it would not shut down from engine overspeed.
Today when I cranked the engine, it started after maybe 10 seconds and the throttle arm moved just slightly to bring a little tension on the idle spring, so nowhere near enough movement to allow for a choke to operate.
After letting it run about about 5 minutes (ran very smooth), I shut it down and tried to restart a minute later to no avail. I should mention that I moved the governor assembly from the old engine to this new engine so maybe something is not set up right with it, but I can't really see what else can be adjusted other than the full load adjust screw which is underneath the air filter housing. I don't plan to put a real/full load on this generator until I can get it to start reliably. I wish I had a 15kw dummy load laying around, but I guess my old 10 seer 4ton AC will have to be that load when I get to that point.
The governor will set both the idle speed and the loaded speed. The lack of tension on that spring is not necessarily an indication of a problem. The no load adjustement is to keep the engine from hunting at idle, and should not be used to throttle back the high speed. If the engine goes to full throttle as soon as it starts, you know the governor is out of adjustment.
I would also assume there is a fuel shut off solenoid near the carb for the gas. There may be a delay between energizing this solenoid and having the proper fuel ratio available in the intake. So I would try turning the key to "on", waiting a few seconds, and then turning the key to start. Some experimentation with different delays may yield a workable solution.
I would also assume there is a fuel shut off solenoid near the carb for the gas. There may be a delay between energizing this solenoid and having the proper fuel ratio available in the intake. So I would try turning the key to "on", waiting a few seconds, and then turning the key to start. Some experimentation with different delays may yield a workable solution.
Stimw
Elite Member
In post #88 the pic of the location, those units are right in front of the window. I would be worried about CO (carbon monoxide) getting in the window with extended use.
If there is any way to route the exhaust out away from the location?
They sell an extension for motorhome generators to remove exhaust safely away from coach. If you could plumb something simuliar it might be wise. At least have a CO detector inside.
Generators have poisioned a lot of people from the simplest mistakes!
If there is any way to route the exhaust out away from the location?
They sell an extension for motorhome generators to remove exhaust safely away from coach. If you could plumb something simuliar it might be wise. At least have a CO detector inside.
Generators have poisioned a lot of people from the simplest mistakes!