Onan Marquis 5000 quits after a while?

[nehuge]

I have a BGM series Onan Marquis 5000 which fires right up. After about 20 minutes it just randomly dies. Then it won't start for 10 minutes or so then will fire up again. Sounds weird, but it seems to do this when it is the generator by itself. With the motorhome's engine running it doesn't seem to do it. Any ideas? It is 1/2 tank full.

[rvten]

I like.many of you ideas. One I am not at home.so things I could do snd the help from other RV onwers in where we live is not available.
I for one can do without the gen. I sit up front and use the engine A/C.
For what a gen cost and the fact many of us do not use them as much as we should.
Another thing. Here on the IL/WI. Line. No mobile RV service. Dealers you can trust. Can be counted witn 0 fingers.

Maybe let DW decide if she really needs it. She can call someone. Onan make a nice boat anchor.

[AWMIII]

Remove the fuel line from the carb and put it in a gas can that is elevated above the carb. Try to run it. If it runs fine, it is the fuel pump. This can be confirmed by putting a cheap low pressure guage on it to confirm it is making 3-6psi.If it still shuts down, then check other things such as carb float and jets. Mine just gave me trouble. It was the metal rod in the mechanical speed control. The Metal had popped out of the plastic bracket. However, your problem really sounds like a fuel pump or carb float problem.

[427435]

A non-RF spark plug may affect other electronic stuff, but they will work fine in the engine.

You can't tell if the fuel lines are tight by "looking" at them. Put a wrench or screw driver on the clamps. It the clamps are spring type, replace them with a worm clamp.

Is the way the genset runs affected by how much fuel is in the main tank?

I had a garden tractor that acted similarly------------it turned out to be the coil. The windings would open up when it got warm enough.

[rvten]

Spark plug is original one.
Fuel conn. look tight.
Gen is clean inside.
Have not found any loose wires.
Could be FP. Gen. Surfers a little just before it shuts down.
Length of time for shut down is about the same each time I run Gen.

Going to try and unused more Carb. Cleaner. If I was home.
This gen would be out on bench.
I would give up a little more space in MH. For a Gen that was easier to work on.
Without having to remove it.

[kmb1966]

mine did this same thing. Started and ran great and would shut down after a while, then hard to start or wouldn't start. For a while, I could wait an hour and it would restart, but only to die again.
Turned out to be the FUEL PUMP. Changed it myself. Very easy to do.
Never had another problem.

[Swamp_Man]

Since I assume this is a gasoline generator, and looking in the manual for the 3600 Onan that I have, sounds like someone changed the spark plug with a non-resistor type. That will cause all kinds of strange behavior. Check your manual and get the correct resistor type sparkplug if you don't have it in the engine at this time. Manual says that non-resistor plugs generator RF energy which can cause strange behavior.

[427435]

Wrong Lane wrote:
I had the same problem last year. Find all the fuel line clamps between the tank and the gennie. I found all of mine were loose to some extent. Tightned all the clamps and problem solved.

Here is a word of caution -- if your fuel filter is the type that screws into the end of the pump, use two wrenches to remove it, one to turn the filter and one to hold the fixed nut on the end of the pump. I decided to save 60 seconds when changing my filter, used just one wrench and caused the end of the pump to fracture. I knew better but thought I could beat the odds and save a trip to my tool box that was all of 20 feet away!

That, friends is a $100.00 lesson on why shortcuts are generally a terrible idea.

X2 on checking fuel line connections.

[rvten]

I have posted on several other forums.
Today was a wasted day.
Replaced FF with help from DW.
I have run out of words to describe todays aggravation.
Bottom line.
I still have same problem

[dcbrewer]

Mine acted the same way, changed the air filter and it started running like new. We run ours while on the road to run roof air. They pick up a lot of dust hanging on the back end . Ours was plugged with only 5500 miles on MH. Now carry a air filter and fuel filter. Good luck!!

[rvten]

Ok I get Code 36.
Changed AF today. Sprayed a lot of carb. Cleaning in today again also.
Checked spark plug and conn.
I have the FF. need to get a deep socket. All mine are not.
Gen. Rustiness. Than starts to surge a little after about 20 or longer than stop sunning.

Thinking FF plugs up. After stopping back flow if any. Cleans it out enough for it to run again for a short time.

[rvten]

OK figured out how to change fuel filter from outside.
Remove hose clamp, than hose and unscrew filter. Will see!!
Thought I had it fixed without doing this. Sprayed Carb cleaner in air intake. Before and while it ran. Was running good. put a little load on it.

Was going to celebrate by having a beer. No trophy. have to replace the filters and try again.

Getting to old to craw under these things anymore.

[rvten]

Wrong Lane
So how did you get to the filter?
Can not get my hand on it. Let alone 2 wrenches.

Stupid design on Onan's part. Put something that needs to be maintained. Hidden in a corner.

[Wrong_Lane]

I had the same problem last year. Find all the fuel line clamps between the tank and the gennie. I found all of mine were loose to some extent. Tightned all the clamps and problem solved.

Here is a word of caution -- if your fuel filter is the type that screws into the end of the pump, use two wrenches to remove it, one to turn the filter and one to hold the fixed nut on the end of the pump. I decided to save 60 seconds when changing my filter, used just one wrench and caused the end of the pump to fracture. I knew better but thought I could beat the odds and save a trip to my tool box that was all of 20 feet away!

That, friends is a $100.00 lesson on why shortcuts are generally a terrible idea.

[rvten]

I will have to try this. Mine just started stopping after running for 10/15 min without a load.
Tried putting a light load on it. Like an air compressor and circular saw. Same thing. Would stop.
When it would stop. It sounded like it was trying to speed up. As if it had a load on it.
Going to try some carb cleaner also.
Trying to figure out how to remove fuel filter from outside. No way I will fit these hands in that tiny filter location from inside.