8 KW Generac oil change. Need advice about foam.

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I've taken over the maintenance of our 8kw Generac generator because the maintenance guy retired. This is my first oil change. Pull up the stick, lots of foam. It's had yearly Mobil 1 10w30 oil changes its whole life. It has a weekly maintenance schedule of approximately 15 minutes. Is there something I can do about this?

Note the oil came out pretty much clean. We've had no extended power outages this year. So it's run minimally.

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Exactly what I was thinking . Is it liquid cooled or air cooled ?

If liquid cooled , maybe the tstat is not letting it come up to " normal " operating temperature or maybe you need to run it for longer periods of time ? Try running it an hour , in cold weather & see if the white foam goes away ?

Does it have a PVC valve / system ? That is not working ?
 
It runs on propane. I don't think it's liquid cooled.. and of course when I take over maintenance somebody before me always put the filter on way too tight can't get it off. It's a special filter size I don't have tools for. So I think I'm stuck till I get the right tools. Why do people do that!
 
Originally Posted by LeakySeals
It has a weekly maintenance schedule of approximately 15 minutes.
it's run minimally.




There's your problem. You're killing it with love.
I would run it far less often, maybe once a month MAX (especially considering it's propane powered and you don't have to worry about gasoline aging or clogging carb jets), and also for a longer period. 15 minutes might be just long enough to get condensation in the crankcase and not burn it off.
 
Originally Posted by LeakySeals
It has a weekly maintenance schedule of approximately 15 minutes. Is there something I can do about this?
Is that 15 minutes at idle or does a transfer switch cut in the target loads? Weekly exercise seems excessive. See if you can cut it back to one 20 minute run per month under load. Most of these standby units exercise once or twice a month, not once a week. There has to be a way for you to change this. Read the manual perhaps?
 
That looks like condensation. Without gasoline to go bad why are you exercising it at all? The purpose of exercising it is to push fresh fuel through the system. The oil doesn't need a workout and the gen-set is just metal parts.

If you must exercise it I would do once a quarter. warm up for 5 minutes then load for another 25 mins. If the oil looks milky youre still getting condensation.

I have a 15 yr old 5kw generac I haven't run in 5 years I got tired of pushing fuel thru it so emptied the tank and ran it dry. I have no doubt if change the oil and put fuel in it would work without issue.
 
Air cooled engine. Condensation from not being run long enough to evaporate moisture in the oil/crankcase. Run the engine for 1 hour let it set check oil after engine cooled off. Repeat til condensation is gone. I would run the system under load 1 hour per month or twice a month. Check dipstick for condensation prior to monthly start. Many variables contributing to condensation. Monitor the condition until you figure out how often to run the unit to keep it condensation free.
 
I have one of these generators, but running off utility natural gas. There's no way to tell it to not run a weekly test; you only get to set the day and time it runs for 12 minutes, which obviously isn't enough time to fully dry it out.

So, I just clean out the mayo every couple of months that collects in the fill/check tube. It doesn't seem to hurt any and looks to be just in the tube.

It's easy to run a load test simply by flipping a breaker to make it think the power went out, but I'm lazy.

And, I'm running Rotella T6 5W30. I think that a better choice than Mobil 1 10W30.

A couple of months ago it was due for its 3rd bi-yearly service, so I just warmed it up and changed the oil. In the past, the spark plug and air filter looked new, so I let them be. I also didn't change the oil filter because the oil always looks perfect. I check the oil monthly. The filter is large for the measly 1.5 quarts of oil.
 
Originally Posted by Asterix
I have one of these generators, but running off utility natural gas. There's no way to tell it to not run a weekly test; you only get to set the day and time it runs for 12 minutes, which obviously isn't enough time to fully dry it out.
Wow! The engineer in me says that this is a bad design, but then he also says it is a design for people who are not engineers.

Originally Posted by Asterix
It's easy to run a load test simply by flipping a breaker to make it think the power went out, but I'm lazy.
I think you might want to simulate that power failure and let it run for half an hour with the target loads once in awhile. Twice a year should do it. Try to aim for maximum loads.

As others have stated, don't worry about the mayo on the dipstick; it won't hurt anything.
 
Originally Posted by Asterix
I have one of these generators, but running off utility natural gas. There's no way to tell it to not run a weekly test; you only get to set the day and time it runs for 12 minutes, which obviously isn't enough time to fully dry it out.

So, I just clean out the mayo every couple of months that collects in the fill/check tube. It doesn't seem to hurt any and looks to be just in the tube.

It's easy to run a load test simply by flipping a breaker to make it think the power went out, but I'm lazy.

And, I'm running Rotella T6 5W30. I think that a better choice than Mobil 1 10W30.

A couple of months ago it was due for its 3rd bi-yearly service, so I just warmed it up and changed the oil. In the past, the spark plug and air filter looked new, so I let them be. I also didn't change the oil filter because the oil always looks perfect. I check the oil monthly. The filter is large for the measly 1.5 quarts of oil.


OK thanks. I was wondering why I couldn't find it on the keypad. Can't figure out how to adjust the time. Worked good today when the power went out. Fired right up within 15 seconds.
 
Does a a propane powered generator need its carb cleaned? Is it at the end of that intake tube? Is there danger because of the propane gas?

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My 10K air-cooled Generac also runs a 10-minute weekly exercise and I have never had a condensation on the dipstick issue. My unit sees -25 degree winter Temps so I run a synthetic 0-30 oil in it. My unit has a manual start control so I can run it and warm it up when I do it's bi-yearly oil and filter so as others have said just crank it up and let it run for a half an hour. Engine only runs at its normal RPM when it's running so it should warm up fast and cook out the condensation. Last tune-up I put a set of iridium plugs in it the originals look good but now with the Iridium is in there I won't have to play with them for a long time
 
Last edited:
Originally Posted by Astro_Guy
Originally Posted by Asterix
I have one of these generators, but running off utility natural gas. There's no way to tell it to not run a weekly test; you only get to set the day and time it runs for 12 minutes, which obviously isn't enough time to fully dry it out.
Wow! The engineer in me says that this is a bad design, but then he also says it is a design for people who are not engineers.


(I am an electronic engineer...) I would rather it didn't run weekly as well, but it won't do that unless you switch it to manual, which defeats the whole purpose of a standby generator.

The power company gives mine a decent run maybe twice a year, but typically for under an hour. From memory, my 6-year old unit has maybe 120 hours on it.

LeakySeals, since the fuel on these is gaseous and not liquid, the carb is not the same as what you're used to. There's no bowl or float. Propane is quite clean, so the whole intake will stay clean. If you're going to work on anything about the intake, shut off the propane. There must be a valve not far from the generator.

Really, the only other thing to do is adjust the valves. Get a new valve cover gasket before you do that.
 
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