Pat Norman
New member
Well my GX670 just started backfiring on cold startup, then runs rough a few seconds before smoothing out. Any suggestions what might be the problem? Never done this before.
Cold Start backfire
- Thread starter Pat Norman
- Start date
outdoorprowash
Member
Sounds like it is flooding. Running rich on start-up and runs good after burning off excess fuel? You may have build-up in your gas tank and in your float valve. When you turn off the engine always turn off the gas. If this fixes the problem then Float valve is getting stuck intermittently. My guess is it's from the ethanol causing corrosion in the fuel system. Could be something else though.
Doug Rucker
Roundtable Host 2009
Air Filter?????????
Vince Wood
Active member
I had a Kohler 15HP that back-fired since day 1 every time I shut the unit off. Never fixed it though, I liked hearing that pop after every job. It let all the neighbors know that I woke up that I was finished.
Alexy
Active member
+1
run it out of gas. Replace the fuel line with EPDM line and take the carb off. Remove the bowl and float inside of it. Clean it out and blow it out as well. Might want to soak the entire carb in carb cleaner then blow it out as well. You will find there is rust from the tank , pieces of deteriorated fuel line and brown varnish from ethanol thru out the system.
Russ Johnson
Equipment Expert
When is the last time you tuned it up?
Pat Norman
New member
I put new plugs and filter about 120 hours ago. I am familar with backfire when cutting off a hot engine, yes that is due to too much fuel. But this happens as soon as I turn the key on a cold engine. Could it indicate valves needing adjusted? Engine has 650 hours. I am going to try some fuel system cleaners like Lucas or Seafoam first.
Paul Kassander
New member
I would guess it needs the valves adjusted but start with some sea-foam to clean out the system first, it may be something simple like that.