Onan7000 problems

[Pastmyprime]

Is it common for the generator not to run when the temperature outside gets above 85 degrees? It will run for a hour or two then shut down. Let it sit for a hour and it does the same thing. This is when I need it most to run the a/c and keep the coach cool. Is there any way to vent generator and get more air to it to cool?

[CJ7365]

Originally Posted by Pastmyprime

Is it common for the generator not to run when the temperature outside gets above 85 degrees? It will run for a hour or two then shut down. Let it sit for a hour and it does the same thing. This is when I need it most to run the a/c and keep the coach cool. Is there any way to vent generator and get more air to it to cool?

You have something else going on.

I have a Onan Marquis Gold 7000 and run it here in the summer time, temps in the high 90s, no problems at all.

On the way to CA, temps over 100 no prob.

I cant really help on why its shutting down


How many hours on the genset

[FIRE UP]

Originally Posted by Pastmyprime

Is it common for the generator not to run when the temperature outside gets above 85 degrees? It will run for a hour or two then shut down. Let it sit for a hour and it does the same thing. This is when I need it most to run the a/c and keep the coach cool. Is there any way to vent generator and get more air to it to cool?

Well Sir,
It might help if we knew the make/model/year of coach and, what model of 7K gen you have. You see, there are different problems with different models/years. And, If it's a diesel, or even some gas units, it will have a lighted ON/OFF toggle switch. If and when your gen has a particular problem, the engine ECM will tap out a code, in the form of "blinks" in that toggle switch.

In other words, if and when that gen shuts down for any other reason besides it's out of fuel, you will get a series of lights on that toggle. It will blink for a series, take a short pause, then blink again. You count the blinks wait for the pause and, count the second set. If say, you get three blinks on the first set, then pause, then three on the second set, that's 3 + 3 or, code 33.

You then find out in the service manual for YOUR SPECIFIC year/model what the codes represent and be guided by their recommendations on remedies. The codes often mean different things on different series of diesel gens.

Scott

[jacwjames]

I own a 7.5KW onan. It is a known problem that the belt will stretch and start to slip causing lower air flow and overheating. There is also a temperature sensor in the cooling circuit that senses this and causes the generator to shut down.

[FIRE UP]

Originally Posted by jacwjames

I own a 7.5KW onan. It is a known problem that the belt will stretch and start to slip causing lower air flow and overheating. There is also a temperature sensor in the cooling circuit that senses this and causes the generator to shut down.

jacwjames,
Well Sir, unless your 7.5QD Onan's kubota engine is configured entirely different from mine, the belt has absolutely nothing to do with the cooling air. The belt is powered from the crank pulley and only powers the water pump. In fact, that belt can come completely off and your cooling, as far as air flow, will still be at 100%. You see, the cooling fan, that provides all the air for cooling that entire system, is attached to the rotor that spins inside of the stator. The belt, is on the opposite end of that little engine from the fan.

The cooling air, starts by being drawn up in the front of the gen itself, through a large holed, debris screen. It's first job is to cool the rectifier and main electricity producing component(s). Then, that air is routed sideways and is forced through the small radiator and then, it's last job is to cool the exhaust/muffler system and finally is ejected out the bottom of the gen, towards the left rear corner, as you stand looking at the front of the gen.

Now, if that belt does break or, become extra loose, yes, it will slow the water pump down a bit which will in tern, impede the flow of coolant but, it's got to be seriously loose for that to happen.

The coolant temp sensor is located on the lower half of the thermostat housing. And, yes, it's known for causing many of the operational issues of the QD7.5. That sensor can even cause hard starting in cold weather due to misguided or improper signals sent to the Kubotas little ECM which then tell the glow plugs to operate at a given time and specific amount of time, based on outside/ambient temps.

Below are a couple of pics of mine when I tore it down for both a sensor replacement and rotor and stator replacement due to one of the magnets on the original rotor dislodging and disintegrating all over the inside of that gen. What a mess! You can see the fan (it's a rotory, not regular bladed fan) attached to the rotor which, you cannot see 'cause it's inside the stator.
Scott

[gruelens]

I had the same issue as the OP. My gasoline Onan 7000 would run fine in cool weather, but shut down when ambient temp was above 80. My research revealed the fuel pumps get tight when conditions are warm, when the pump gets some age to it. A new fuel pump corrected the problem for me.

[Atom Ant]

If not moving, my 8K shuts down from high temp when trying to run 3 ACs. It does fine with 2 ACs. I think it has something to do with mine being variable speed, which may not be the case with the 7.