NEW LPG CONVERTER WORSE CONSUMPTION

[Dannyroger]

The truck has been nice for quite a while, then suddenly wasn't idling properly and died on deceleration.
Did the normal MAF & throttle cleans, pipes and connections etc plus cleaned the gas mixer and checked connections, no better. So reluctantly took it to a LPG mechanic who diagnosed a stuffed converter with a porous diaphragm "dumping gas like no tomorrow". So he installed a new converter + new safety relay.
Now the car runs nicely, but my gas consumption is about 25% WORSE.
Got him to check it and he said his analyser said it was perfect, but gas consumption is definitely worse than it was (about 27l/100 now vs 21l before).
Huh? A leak? Tuning? Misassembly? Wrong mechanic?
Any help appreciated.

98 D1 V8 200K basic Impco lpg B2 convertor/200 Mixer

[bee utey]

There is a mixture adjuster on the mixer marked "L-R" move it one notch towards "L" and see how it goes. The new converter has no adjustments. Also check that the ignition timing is set to around 10 degrees BTDC.

[Dannyroger]

Thanks bee utey. Actually I don't know where I got the"200" from. This is the mixer but I can't see the "L-R" adjustment - do you mean the big screw adjuster top right?

[bee utey]

Thanks bee utey. Actually I don't know where I got the"200" from. This is the mixer but I can't see the "L-R" adjustment - do you mean the big screw adjuster top right?
That is what is sold as an Impco model 200 mixer. The visible screw is the idle mixture screw and doesn't affect the economy under load very much. The lean-rich adjustment you need is adjacent to the LPG inlet hose and is connected to a flat vane that partly blocks the gas flow as you turn it. It is usually hard to get at as it faces the engine. I think you can move it with a 14mm flat spanner. You may have to remove the mixer to access the adjuster.