QuestionI have a Thermal Arc welder powered by a Honda GX 620 engine. It starts easily, but only runs for two to three minutes. It will restart immediately, but only runs for two to three minutes. I have changed the fuel filter and hoses, no change. I have also tried running the engine with the fuel cap loose (heard that there might be a vacuum created in the tank), no change, still runs for two to three minutes.
AnswerInteresting...have you replaced the spark plugs?
Does the engine have a low oil sensor?
Have you checked the carburetor fuel solenoid?
Fuel pump issue? Copy and paste this URL...read all the webpages.
https://www.briggsandstratton.com/eu/en/support/faqs/servicing-the-fuel-pump
Since it starts right back up it's going to be difficult to narrow the problem down right away. You will have to verify the fuel pump, solenoid, and I would have a multimeter connected to the regulator to check the power output to make sure the regulator it not malfunctioning causing issues with the fuel solenoid.
Good call on the gas cap...bad gas caps can be very difficult to isolate/troubleshoot.
One other tool that might help troubleshooting is an inline spark tester to verify the ignition modules are not faulty...but I find it hard to believe both would be bad causing the problem.
Are you absolutely sure the fuel hoses and vacuum line on the fuel pump are not leaking?
Eric
