Okay it's not a car, it's in a generator, but I couldn't find anywhere better to ask.

I've got an GX620 Honda V-TWIN it runs fine on petrol but won't run on lpg, it's meant to be dual fuel. If I block half the air intake it will run, but doesn't have enough power to cope with any load. Runs fine without blocking air inlet on petrol, and has full power etc.

Anybody any thoughts?

  • So what's the gas control system - what have you checked? – Solar Mike Feb 24 '19 at 20:40
  • It has a Garretson KN system, I've tried swapping it for another unit, with the same result. Basically it uses the vacuum to open a valve by way of a diaphragm – dragonfly Feb 24 '19 at 21:15
  • Disclaimer, never used a dual fuel engine... If you block the intake and it runs that means it's either getting too much air or not enough fuel. What's responsible for adjusting the fuel/air ratio when you switch fuels? – JPhi1618 Feb 25 '19 at 20:43
  • That is my thinking, the vapouriser has an adjustment, you can't adjust it to give enough fuel, which leads me to a possible vacuum leak, but I've checked and can't find one. Plus a vacuum leak would more than likely effect petrol which it isn't. I have had as suggest that lpg needs a stronger spark, so if my coils are getting weak it's possible it may fire petrol but not lpg, but remain to be convinced. – dragonfly Feb 26 '19 at 21:20

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.