Generator Problem - Montana Owners Club

Mudchief · 06-07-2007, 07:46 AM

On our trip to the Northeast Rally I found out the generator would quit after 20 minutes of running. What is happening is the exhaust air blow down hits the ground and is sucked back up into the return causing the unit to over heat and shut down. Keystone says it's a ONAN problem and ONAN says it's a Keystone problem. I'm in the middle. However if my buddy OZZ has a metal break I will fix it myself. Just want to let those that order the unit with a generator to be aware of the problem.

Ozz · 06-07-2007, 10:31 AM

No break, but have a sheet metal shop handy for our needs.
Just let me know when.
My sharp little wifey asked if it was vented to the side, would that fix the problem??
Ozz

Mudchief · 06-07-2007, 12:14 PM

OZZ, Sue is right. Just need to vent the exhaust to the side so it won't be sucked back into the cool air intake. You would think the design engineers would be smart enough to know that you don't put the hot air exhaust next to the cool air intake without some kind of deflection. Glad you have a sheet metal shop handy. If the fight between ONAN and Keystone is not resolved soon I will give you a call. It will be simple to correct.
Thanks

Ozz · 06-07-2007, 12:37 PM

I'll be here for you, my friend.

lwcdg · 06-07-2007, 12:42 PM

Mudchief, I haven't seen the new installs of Onan. Our dealer installed our Honda 5500 they put the genset on the door side and then went under the RV and over to the other side with the muffler and exhaust. Plus they turned the last 18 to 24" of pipe at a 30 degree bend to kick it even further away from the bedroom window. We've never had any exhaust fumes odor or problem. I'd look into the exhaust before putting in some sort of deflector. But I'm sure you and Ozz will come up with the correct solution.
Good Luck,
Chuck

Mudchief · 06-07-2007, 02:27 PM

Chuck, it is not the exhaust pipe that is the problem but the air cooling the engine. It pulls the air up from the bottom circulates it over the engine and blows it back out the bottom. The hot air hits the ground and is reflected back up where it is sucked back into the engine. Therefore you do not get cool air coming back into the engine for cooling. The deflector I am talking about is for the hot air not the exhaust fumes from the engine. The exhaust pipe is about 8 feet long and I do not get any fumes into the unit.

lwcdg · 06-07-2007, 02:47 PM

Mudchief, I bow to your knowledge. I didn't understand the "intake" issue. I could only think of "heat" coming from the exhaust. I've never had an intake problem with ours and have run it for 8 hours or more a couple of times. (power outages) I'll check ours and see if I can come up with any "quality" ideas to help.
Chuck

Russ and Sandy · 06-07-2007, 03:27 PM

I've never noticed any heat problem either, but our unit was built with a intake air vent in the door compartment door. I noticed Keystone stopped doing that somewhere along the line.

Ozzie · 06-07-2007, 04:10 PM

I wish I was nearby to help...many years of sheet metal fabricating under my belt. I'm sure you and Ozz can handle it just fine.

Mudchief · 06-08-2007, 12:42 AM

Thanks Bruce, By the way the screen door you fixed for me in Branson is still working great. We have pulled the unit over 2800 miles after leaving Branson. i also put a slight offset to the bike spoke mod you added and it now clears that latch that it was hitting. Thanks again for doing that.

Redrover98 · 06-08-2007, 01:12 AM

I have an Onan in my 07 Tana and have run it for 2-4 hours with no problem. However, I had gone to Lowe's and bought a white air conditioner return air grill and installed it in the door. It has a channel for a filter and the color is almost a perfect match. I bought one of the blue cut to size, washable filters for it. It helps keep road grime and water from the rear tires out of the comparment.

bsmeaton · 06-08-2007, 11:42 AM

Dennis,

Good info to know. I've actually never had a problem with the 5500, but doesn't mean I won't. I least I'll know what to look for. I was just thinking I would open the front door, but doesn't really matter does it? Nothing vents or circulates above the base on the Onan.

Mudchief · 06-08-2007, 12:32 PM

Brad, that is the way I found out I had a heat problem. I open the front door and removed the front cover of the generator and it would run until I turned it off. Going down the road I would crank it with the remote and when we stopped to eat it was nice and cool inside. But in 20 minutes it would shut down. I'm sure the hot pavement in the rest area's added to the problem. The Dealer is working with both ONAN and Keystone to resolve the problem. They both know there is a problem. I found out I am not the only one with this issue. I'm sure they will get it resolved if not OZZ and I will fix it.

k0nsa · 06-09-2007, 01:51 PM

Our new 3400RL just arrived at the dealer last Thursday and while the Wife and I were checking it out today, I noticed that we have a solid baggage door over the front compartment where the Onan generator is. When we ordered it our sales guy said that it would be a vented door when with the generator installed. From reading the comments in this topic is sounds like Montana changed that and that door is no longer a vented door and the cooling is handled via openings beneath the generator. Can anyone with a newer unit confirm that? Just want to know if I need to talk to my sales guy about this. Thanks!

Mudchief · 06-09-2007, 05:10 PM

K0nsa, The new style ONAN does not require a vent in the door like the old units. You might want to let the unit run for a hour at the dealer to see if it shuts down like mine. It may just be something with the size of the generator mine is a 7KW.

bsmeaton · 06-09-2007, 05:39 PM

Bill,

Dennis is right - learned that myself through the MOC. I kept running around the Dealer lot trying to find a door with the vent so I could look at the generator prep. No longer need the vent in the door.

If you look at the case around the Onan, it all sealed above the base, so a vent in the door wouldn't really do anything.

k0nsa · 06-10-2007, 01:39 AM

Great, thanks for the Information!!

01RAMer · 06-26-2007, 09:33 AM

Quote:

quote:Originally posted by Mudchief

K0nsa, The new style ONAN does not require a vent in the door like the old units. You might want to let the unit run for a hour at the dealer to see if it shuts down like mine. It may just be something with the size of the generator mine is a 7KW.

I had an overheating problem and it turned out that the knockout hole in the bottom of the front compartment was too small for the Onan Genset, which partially covered the exhaust side of the genset cooling port. This pushed the heated air back toward and into the intake side causing a cycle of increasingly hotter air for cooling, till the genset finally shutdown due to overheating.
By opening the hole completely and adding a piece of metal to divide the two sections with a flare on the bottom of the metal pointing toward the exhaust, to add additional direction to the hot air, I now have no overheating problems. My front storage compartment door is solid and I always leave it closed and use the remote start without problems.

Mudchief · 06-27-2007, 02:57 AM

01RAMer, That is the problem I have. I have cut out the hot air vent hole to the proper size. I have made a divider with a 45 degree offset to deflect the air to one side. I also re-routed the wiring because it was in the path of the hot air and had already started to melt. Thanks for the information I hope to have it finished by tonight and I will post some pictures for others that may have this problem.

01RAMer · 06-27-2007, 06:18 AM

Quote:

quote:Originally posted by Mudchief

01RAMer, That is the problem I have. I have cut out the hot air vent hole to the proper size. I have made a divider with a 45 degree offset to deflect the air to one side. I also re-routed the wiring because it was in the path of the hot air and had already started to melt. Thanks for the information I hope to have it finished by tonight and I will post some pictures for others that may have this problem.

Yeah, I rerouted wires also as mine too started melting. I would recommend that for everyone.

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