Tuning LPG System help.

Joined: 17 Dec 2003 Location: South Side Brisbane

Hey all,

Just did a service on the Mav and it seems to have thrown the tuning of the petrol / lpg system out. Now Im pretty confident I can tune the petrol side of things , reading the manual its just the normal mixture / idle settings..

Now, my worry is the LPG system, ive never touched one of these before. Its a IMPCO 300 system I think, on top of the air filter it has a gas feed going in and that has a nut on the top, L R on one side of it and POWER on the other.

Now im hoping that basicly the carby with still look after the idle side of things and the only adjustment for the gas would be mixture.

Now has anyone here tuned these before? any help would be muchly appreciated.

Thanks guys.

Joined: 24 Oct 2002 Location: ACT

the big L-R knob is the open throttle mixture. mine and others I have seen all end up set down pretty close to full lean, about halfway between the last 2 marks. under the 1/2" nut on top (right in the centre of the spigot) is the idle mixture screw. the nut is just a dust cap really. if it is not idling, it is probably too rich. the screw is the same as any other mixture screw. in is lean, out is rich. it is on a spring though, so when you are turning it don't let the weight of the screwdriver and your arm rest on the screw,cause it will push it down leaner, then when you take the screwdriver out it will run rich again. be delicate!
mixture is all you need to tune. volume is controlled by vacuum through the carb..

Joined: 17 Dec 2003 Location: South Side Brisbane

Thanks for your help Wendle,

Is the tuning procedure that same as petrol, basicly lean it out until it reaches max idle speed ?

Joined: 24 Oct 2002 Location: ACT

Draven wrote:

Thanks for your help Wendle,

Is the tuning procedure that same as petrol, basicly lean it out until it reaches max idle speed ?

yeah, when you think you have it right, thump the throttle a couple times, it will settle out. and just set it to slightly rich of perfect, your valves will thank you!

Joined: 17 Dec 2003 Location: South Side Brisbane

Excellent!, Thanks mate!