Tuning LPG?

Submitted: Tuesday, Jun 12, 2007 at 19:51
ThreadID: 46586 Views:13528 Replies:5 FollowUps:1
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Hello,
Have a GQ 4.2 that has been converted to gas and was wondering if anyone can tell something about the function of the 2 screws, one of which is spring loaded, located at the back of the converter? There is also a larger spring loaded adjuster located at a junction in the hose going from the converter to the ring that sits above the carbie that I'd like to know about as well. Any insights will be greatly appreciated.
troy
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Reply By: lifeisgood - Tuesday, Jun 12, 2007 at 21:31

Tuesday, Jun 12, 2007 at 21:31
It raises the point that it would be nice if the Gas fitters provided a small operation manual which spelled out the usual mode of operation , Listed parts used including relays - for spare parts ordering down the track and a diagram of the whole assembly. If something goes a little wrong you (or your bush mechanic ) could at least have some idea of whats what!
AnswerID: 246441

Reply By: Graham & Lynne - Tuesday, Jun 12, 2007 at 21:36

Tuesday, Jun 12, 2007 at 21:36
spring loaded screw on converter is idle mixture adjustment you can adjust it you will notice idle speed change set it in middle where runs best.
Screw @ junction is top end i.e. full load you should never need to adjust it.
Graham
AnswerID: 246445

Reply By: Allan F (Gold Coast) - Wednesday, Jun 13, 2007 at 06:44

Wednesday, Jun 13, 2007 at 06:44
Hi Troy,
Most gas converters have 2 adjusting screws, the larger is usually the sensitivity adjustment and the smaller one is the mixture adjustment. There is also a large adjuster screw in the hose from the converter to the mixer. This is the high speed adjustment.
Cheers Allan
AnswerID: 246487

Reply By: Member - Greydemon (WA) - Wednesday, Jun 13, 2007 at 12:49

Wednesday, Jun 13, 2007 at 12:49
Do these comments apply to the direct injection version as well? Mine is newly fitted and I was going to take it back this week for its first 'free' service as it is idling a bit rough but if I can fix it myself I can save the free service until it is really needed.
AnswerID: 246557

Follow Up By: Graham & Lynne - Wednesday, Jun 13, 2007 at 19:11

Wednesday, Jun 13, 2007 at 19:11
Greydemon (WA) what brand is your direct injection?
As far as i know there are no external adjustments on direct injection of LPG
I work on today the commissioning a "VERSUS" one and is done on a laptop.

cheers Graham
0
FollowupID: 507431

Reply By: troy10 - Thursday, Jun 14, 2007 at 19:14

Thursday, Jun 14, 2007 at 19:14
Thanks for the reply's as they have helped confirm some other sources I've been looking at. Would I be correct in thinking that as you adjust the mixture screw clockwise, moving it inward, that the mixture become leaner? I couldn't help but notice that you can realy smell a noticeable increase in that LPG exhaust smell as you adjust the mixture outward which would seem to indicate a richer mixture. Both extremes of this adjustment result in very rough running engine.
AnswerID: 246840

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