M923 dies on acceleration

I’ve got a fuel issue(?) with my 923. It will idle great but when you press the accelerator to go, it runs up a couple hundred RPMs then dies. RPM drops to around 400 and it “starts” and runs back up to normal idle.

If I press the accelerator slow, it’ll get to 2000, then it does the same thing.

I’ve replaced the fuel filter, the small primer line, and Orings in the primer pump. Used the air pressure trick to purge the fuel system, even left the hose on to pressurize the tank when running. Still dies on acceleration.

Is there an over speed solenoid someplace that’s bad? Think it's the fuel shutoff solenoid de-energizing? Does that sound like a bad pickup tube in the tank? Thanks for any help!

Sidebar, I've got to jump it to start, but the generator should keep voltage steady for the motor, right?

skuhler said:

I’ve got a fuel issue(?) with my 923. It will idle great but when you press the accelerator to go, it runs up a couple hundred RPMs then dies. RPM drops to around 400 and it “starts” and runs back up to normal idle.

If I press the accelerator slow, it’ll get to 2000, then it does the same thing.

I’ve replaced the fuel filter, the small primer line, and Orings in the primer pump. Used the air pressure trick to purge the fuel system, even left the hose on to pressurize the tank when running. Still dies on acceleration.

Is there an over speed solenoid someplace that’s bad? Think it's the fuel shutoff solenoid de-energizing? Does that sound like a bad pickup tube in the tank? Thanks for any help!

Sidebar, I've got to jump it to start, but the generator should keep voltage steady for the motor, right?

Click to expand...

NO !

You need to have good batteries to diagnosis electrical issues . Turn the bypass out on the fuel shut-off and see if it still dies , then correct your electrical issues.

Delete the primer pump. Just cause you replaced that crap doesn't mean anything. Add an 1/8" pipe plug to block it off. If you have the fuel tank with a air fitting on it then you do not need a primer pump. Run a line from your fuel filter inlet side to a 5 gallon tank of fuel and see what it does running on a different fuel supply. IF you still have the same issue then you need to replace the inlet fuel line from the filter to the IP with a known good line to start before you want to look at anything internal.

Also make sure that the return line is properly tightened on the IP.

That bypass, you turn a thumbscrew clockwise to bypass the fuel shut off, right? That's up on the IP? What's that tell me, that the shut off solenoid is losing energizing because of the batts?

Yeah, that battery issue, looks like I got one of four that's bad. It's expensive, but don't you need to replace all 4 at the same time?

skuhler said:

That bypass, you turn a thumbscrew clockwise to bypass the fuel shut off, right? That's up on the IP? What's that tell me, that the shut off solenoid is losing energizing because of the batts?

Yeah, that battery issue, looks like I got one of four that's bad. It's expensive, but don't you need to replace all 4 at the same time?

Click to expand...

You can run just 2 batteries you do not need all 4.

The battle mode knob should screw in to override the electrical side and allow continuous fuel flow

does it lose rpm when on a full tank as well, or only on a partial tank of fuel? i had a similar issue that was my dip tubes, both intake and return were bad. I replaced with new stainless ones form Tomcat and was good to go, no more issues. So if not sure fill fuel tank all the way to full line. If problem seems to go away should be the dip tubes. also, if not dip tubes, could be a bad fuel line where there is air getting in fuel lines.

Just to verify, this I just a 923 right? Not an A2? Makes a world of difference in diagnostics.

You nailed it. The solenoid was losing voltage and closing. Thanks for your help!

simp5782 said:

You can run just 2 batteries you do not need all 4.

The battle mode knob should screw in to override the electrical side and allow continuous fuel flow

Click to expand...

I dropped down to two group 31 batteries for my A2. Starts it just fine. Much cheaper this way. Fyi