GX670 quitting with load

Good evening,
I hope someone here can help me out. My name is Andy, I own and run Horizon Power Wash, LLC. in South Florida. This is a new business for me and I’m just getting my feet wet on my own.
I have a GX670 with a 4500psi 8gpm pump. The problem is once the engine is running and I squeeze the trigger on something the engine rpm’s seem to drop really low. If I release the trigger, they come back up. This happened today while running a 20" Whisper Wash. When I squeeze the trigger I can only effectively clean for 2-3 seconds before the RPM’s drop out sometimes the engine will run for a few minutes and then it shuts down.

Thoughts and ideas are welcome,

Sounds like the main jet in your Carb is dirty or clogged. When the trigger is squeezed the motor is put under load and requires more fuel from your main Jet. Idle jet takes over when its not pulled. If you are going to take a crack at cleaning your carb and you are not familiar with this I would suggest taking it to a shop or getting someone to help. Carbs are normally full of tiny easy damageable or easily lost parts.

Good luck :slightly_smiling:

I had a similar problem recently - It was a bad (cracked) spark plug.
Could also be a coil.
Good luck.


You might also just check your nozzle sizes against a chart. You might be bogging the engine way down by trying to push 4500psi and 8gpm off of that engine. 8gpm, 4500psi requires over 32 hp by my math (gx670 might be around 24hp).

Thanks a lot for the great input. Looks like she’s going in to dry dock for repairs.

I just wanted to follow up for those that provided an opinion.

We almost had a winner, Evanwindows was close. There was a fuel delivery problem, just not with the carb jets. The fuel hose between the filter and the bottom of the fuel pump was dry rotted and kinked. Also the wiring to the fuel solenoid was “clipped.” Maybe this was done by the previous owner who knows. All is well now.

Thanks again!

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