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faulknerice · 07-18-2011, 05:28 PM

I have a Generac 40 QP Gas generator on my 2007 class c It over heats when running the ac when the temperature is in the mid 90's

I have done the following
shut down all but ac
installed a hard start cap in ac
new spark
clean carb
syn oil
new air cleaner
adjusted valve lash
checked cooling fan

any one else have problems with generators overheating in 95+ temps with ac on

bearaboo · 07-19-2011, 11:06 AM

Is it shutting off because of overheating? You might try running the gen with cover off and the compartment door open. I have same gen and it only shut off once when it was real hot in Yellowstone NP.
Let it sit for awhile and restarted. Have not had any problems since then, even though
I have run in it some very hot temps. Seems like you changed all the combustion parts except the fuel filter.
My sense is that it is an electrical issue within the generator. Reaches a certain temp and shuts down. Don't mean to a wise guy, but is there more 1/4 tank of gas?

faulknerice · 07-19-2011, 02:03 PM

Quote:

Originally Posted by bearaboo

Is it shutting off because of overheating? You might try running the gen with cover off and the compartment door open. I have same gen and it only shut off once when it was real hot in Yellowstone NP.
Let it sit for awhile and restarted. Have not had any problems since then, even though
I have run in it some very hot temps. Seems like you changed all the combustion parts except the fuel filter.
My sense is that it is an electrical issue within the generator. Reaches a certain temp and shuts down. Don't mean to a wise guy, but is there more 1/4 tank of gas?

Thank you for the idea
I have a new fule filter on order allready
the gass tank is full
and if the temp is below 90 it will run all day no problem
it is over heating i used a infered temp gauge on the oil sensor and it was 270 the shut down temp is 264

I think that maybe this generator are not designed to work in 95 or 100 degrees with high humidity they say ac takes 20 to 30% more juice at that temps and generators loose power 1% fo every 10 degrees after 80

3600 w gen
-3% 108 w
=3492 w
can a 13.5k ac unit working 30% harder =3500 w?

Mr_D · 07-19-2011, 02:07 PM

Quote:

Originally Posted by faulknerice

I have a Generac 40 QP Gas generator on my 2007 class c It over heats when running the ac when the temperature is in the mid 90's

I have done the following
shut down all but ac
installed a hard start cap in ac
new spark
clean carb
syn oil
new air cleaner
adjusted valve lash
checked cooling fan

any one else have problems with generators overheating in 95+ temps with ac on

Yes, we had a 6.2 Kw propane Genajunk unit in our 2000 DSDP, Would over heat and blow the circuit breakers above about 2,500' in 90°-95° weather. It never totally shut down, just blew the breakers though.
We now have a liquid cooled diesel 8.0 Kw gen, will never own another propane unit!

mahon1993 · 07-19-2011, 02:26 PM

I have seen guys use small portable 120 volt fans to blow on the geretator.
Greg

lowpasslew · 07-25-2011, 04:02 AM

Yes, brand new jayco class C quits when it gets over 95 degrees. Took it accross to Las Vegas and suffered. Generator people had no idea or suggestions.

faulknerice · 07-25-2011, 08:06 PM

I have a idea for a mod
Has any one ever put on a oil cooler on a gen set
I was thinking i could buy a car oil cooler kit
they go on the oil filter and are about $150

what do you think

Gma-n-Gpa · 08-08-2011, 12:56 PM

lowpasslew - interesting my 2011 Jayco displayed similar performance on last week's trip to Black Hills - Gen worked great when coach standing still (95+ in Badlands) but quit within 5 minutes after we started moving... Gen ran great when stopped at the BH campground. On return to Iowa wife and grandkids watched movies on gen no problems; within 15 minutes of running A/C gen died again. Going to Onan on Wed will post their "answer"

tcopeland · 08-09-2011, 09:31 AM

Please let us know outcome with Onan visit!

lowpasslew · 08-10-2011, 02:36 AM

We were told by Jayco Headquarters to take our 2011 RV to the Cummings-Onan dealer when we got home in Orlando, FL. Took it in yesterday. People were very nice, said they had similar problems, several possible causes, they would evaluate it. They said not to use synthetic oil, which I had used after the generator was well broken in, so we are switching from Amsoil back to regular. If we had an oil problem, synthetic would invalidate the warranty

. I wonder if they really know what they are talking about??

I also mentioned use of cooling fans or an oil cooler connected to the oil cooler. They acted like they had never heard of that, but would consider it. So we will wait and see. Having an RV that doesn't work in hot weather seems like a waste of $69,000. The overheating experience almost killed my 96 year old passenger during our trip.

I'm not a lawyer, but a medical person.

Davinger · 08-10-2011, 05:54 AM

I work with computers a great deal and heat is a major issue. One of the first things to look for when overheating is insulation. Over time things build up around things and dust and road oil can start to accumulate on both the outside of your generator and the compartment it is in. Sometimes a good cleaning of both the unit’s exterior and the compartment it is in will allow more air flow. Most of the generator compartments have vents and if they become clogged it can stop the flow of air. Just like dust on the fans of your computer. I hope this helps.

Gma-n-Gpa · 08-10-2011, 06:56 AM

Davinger - Agree with you 100% - heat can kill electronics - in my case the coach has less than 5K milles so don't see accumulation of dirt as a major contributor. I will add the vents and gen compartment to my checklist. Thanks for the info.

lowpasslew - So other than blasting you for synthetic oil and "considering" a cooler, did the Onan dealer have any ideas to solve this problem? I am with you, a coach without aux A/C in the summer is pretty useless. Hope your 96 year old passenger is doing well after that experience..

bearaboo · 08-10-2011, 02:45 PM

Interesting that you mention the synthetic oil. The one time my gen shut off in Yellowstone, that was my first thought. Maybe low oil pressure. Even bought a quart of regular oil to change it out if necessary. Hasn't happened again and I continue to use Mobil 1 10W-30.

lowpasslew · 08-10-2011, 08:33 PM

Quote:

Originally Posted by Gma-n-Gpa

Davinger - Agree with you 100% - heat can kill electronics - in my case the coach has less than 5K milles so don't see accumulation of dirt as a major contributor. I will add the vents and gen compartment to my checklist. Thanks for the info.

lowpasslew - So other than blasting you for synthetic oil and "considering" a cooler, did the Onan dealer have any ideas to solve this problem? I am with you, a coach without aux A/C in the summer is pretty useless. Hope your 96 year old passenger is doing well after that experience..

I contacted Amsoil headquarters and they thought it was OK to use their product unless the Onan handbook or spec sheet said no. Onan dealer said nothing was in writing, but they had seen a couple instances where synthetics were suspected in poor ring seating. That is like me taking my person experience instead of my periodontal specialist training in dentistry. They still have my RV. I'll keep you posted on the results. It seldom gets over 95 in Orlando, so I won't really know until I venture into superheated conditions again.