stalling 2.8 KV Onan MIcrolite 2800 watt generator

[tinman176]

I have a 1992 B-190 Airstream Van motorhome with factory installed A/C and Generator.

My problem is that I installed a new caburetor in order to make my generator work efficiently, as it was becoming harder and harder to start and run self contained appliances and A/C.

After installing the carb the generator worked very well from the start while not under any load,however when I either use the microwave or the A/C the generator stalls out.

I used a meter that measures voltage,Hz, frequency,resistance, and several other measurements to adjust the governor and speed controls to bring the unit into specs laid out by Cummins service manual.There is no loss of motion or binding on the governor linkage.

Has any on any ideas or suggestions on how to bring a remedy to this problem? Thank you in advance for any help offered. tinman176

[Mr_D]

Wrong carb or jetting? Does the linkage move when you add load? It should do something to take up the load of the load cutting in.

[jlyon69]

From what you have described, everything points to the new carburetor. When you said: "I installed a new caburetor in order to make my generator work efficiently" were you trying to save fuel? If so, the only real way to do this is to "lean" out the carburetor. If the genny is running lean under no load, it will most likely stall when a load becomes present, this is due to not enough fuel.

I would check to be sure the new carb is a direct replacement for the old one. If there is any adjustment on the link between the governor and carb, that could be off enough to starve the engine of fuel. If you have an altitude adjustment, be sure it is set properly. I have to assume the carb has an accelerator pump of some sort to deliver a good shot of fuel when a load quickly arises. Check anything you can there.

Failing that, I would slowly richen the carb and make load tests to see if your problem gets better.

[tinman176]

Originally Posted by jlyon69

From what you have described, everything points to the new carburetor. When you said: "I installed a new caburetor in order to make my generator work efficiently" were you trying to save fuel? If so, the only real way to do this is to "lean" out the carburetor. If the genny is running lean under no load, it will most likely stall when a load becomes present, this is due to not enough fuel.

I would check to be sure the new carb is a direct replacement for the old one. If there is any adjustment on the link between the governor and carb, that could be off enough to starve the engine of fuel. If you have an altitude adjustment, be sure it is set properly. I have to assume the carb has an accelerator pump of some sort to deliver a good shot of fuel when a load quickly arises. Check anything you can there.

Failing that, I would slowly richen the carb and make load tests to see if your problem gets better.

Hello and thank you for your assistance and advice.I was not trying to save fuel or any other economy measures.The generator under the old carb was becoming increasingly harder to get started.I have checked and rechecked the carb adjustments as well as the governor adjustments many mant times in the last several days, and the best that I can get out of the generator is that I can operate the toated inone of the outlets,and when I start the microwave the generator starts to sputter and then runs on regularly.As far as the A/C goes I have not had any luck getting that going in the regualar way.However if I turn the A/c on and then start the generator the A/C will run and cool the RV.This all does not seem right since I have never had this problem previously.I may have to resort to going to Cummins and spend a $100.00 per hour to get them to diagnose what is wrong with my adjustments.In any event thank you again. Don

[jlyon69]

I am no expert on generators...all I can say is the generator is not able to cope with an initial large load, which tells me governor is not compensating enough or perhaps not fast enough and/or the carb is not doing what the governor wants.

How does the A/C respond when you are plugged into a 15amp outlet? Any notice of a slow response? What I'm thinking is the compressor may be getting bad and is generating too much initial surge that the generator cannot handle.

Other than that, since your generator is capable of 23amps continuous, I would slowly turn on 120v appliances until you get to 2500 watts or so. You could accomplish this slowly with say a 1500W hair dryer and a small space heater, also around 1500W max. Start one on LOW, then the other on Low, just keep alternately adjusting them higher until you are sure you're in the 2500 - 2800W range. If everything works as it should, your engine/generator is doing what it was designed for. Now you are sure it's a problem with compensating for surges.

After more thought....

The fuel filter could be partially blocked limiting fuel flow when need. I would check and/or replace that. It could also be a faulty fuel pump, doing the same thing. Could be why it started acting up in the first place. Deeper than that (with my fuel starvation theory) could be a kinked fuel line or it's cracked allowing air to enter the fuel supply.

[tinman176]

Originally Posted by jlyon69

I am no expert on generators...all I can say is the generator is not able to cope with an initial large load, which tells me governor is not compensating enough or perhaps not fast enough and/or the carb is not doing what the governor wants.

How does the A/C respond when you are plugged into a 15amp outlet? Any notice of a slow response? What I'm thinking is the compressor may be getting bad and is generating too much initial surge that the generator cannot handle.

Other than that, since your generator is capable of 23amps continuous, I would slowly turn on 120v appliances until you get to 2500 watts or so. You could accomplish this slowly with say a 1500W hair dryer and a small space heater, also around 1500W max. Start one on LOW, then the other on Low, just keep alternately adjusting them higher until you are sure you're in the 2500 - 2800W range. If everything works as it should, your engine/generator is doing what it was designed for. Now you are sure it's a problem with compensating for surges.

After more thought....

The fuel filter could be partially blocked limiting fuel flow when need. I would check and/or replace that. It could also be a faulty fuel pump, doing the same thing. Could be why it started acting up in the first place. Deeper than that (with my fuel starvation theory) could be a kinked fuel line or it's cracked allowing air to enter the fuel supply.

Hello again.I would not believe it if I did not see it with my own eyes.Each and every time I placed the generator cover back on to the unit I did not notice that a very small corner of the molded fibreglass insulator was just barely touching the end of the governor preventing full free movement of the governor arm.Once I was able to keep the governor arm free, the generator started beutifully and powered up when I called for the A/C or microwave to come on.It was particularly hard to see, but I did find it under close examination.Thank you again for your input, and suggestions and I wish you and your family a very prosperous new year. Don