Gas system - running, timing etc please help

[RRV80]

1984 Dual carb 9.35:1comp - stil running points.

I am going for a gas certificate tomorrow for RWC and all he want is for it to run on gas, doesnt have to run well, just has to run.

So i put 45L of gas in it tonight. and 20L of 98 octane petty, (was empty )

When i got it, the vaccum advance plate was disconnected, the points could move all over the place, the timing was out and was genrally not running well, however it would run on gas and petrol reasonably well. It would not start on gas at all, and sometimes not on petrol, and if it stopped/stalled on gas it wouldnt start again on either for days.

So what did i do, i fixed all the internalls of the dizzy, repaired the vaccum advace unit, adjusted the timing, replaced, leads, coil, cap, rotor button, spark plugs, point etc. Now it runs absolutly fantastic on petrol, When i first switched it over to gas tonight, it ran, albeit not well, but was running, the exhaust sounded funny and sounded as if it may have been missing a touch and then the idle just dropped and dropped and dropped till it died. So i switched it back to petty and fired up straight away, flicked over to gas, and it didnt like it at all and pretty much died straight away, i then tried starting it on gas and flickin the swtich a few times priming the solenoid, and pressing on the accel a bit it turned over coughed and turned over and started and then dies.

So to me it sounds like a timing related issue, for this exercise i dont care if it doesnt run on petty, i just want ti good on gas now i know i can start it on gas. I think it is set to 8 degrees, the manual says 6 degrees, i cant remeber wether it is ATDC or BTDC. is 6 advanced or retarded from what i have it now? what should it be, for the problem i am having should i retard or advance it? or what else should i try?

thanks again for all you help in advance.

[crossy]

Are you doing all this with the air cleaner fitted? Makes a huge differance on gas. To me it doesn't sound like a timing problem.

[Disco300Tdi]

possibly the air/fuel mixture on the gas

[lokka]

Increase the gas flow as it sounds like a fuel problem has the line between the condenser unit and the carbies got a adjustable screw if so wind it out a turn or 3 and try it again if no luck adjust the mixture screw on the condenser to in crease the fuel

cheers

chris

[loanrangie]

When i had my dual fuel rangie i had the timing at 12 btdc and it ran fine on lpg and pet, sounds more like the dashpots in the carbs need a top up or some fine tuning on the sensitivity screw of the converter. You need good leads ,rotor, cap etc for lpg and a better dizzy is a big improvement.

[jasper110]

timing on petrol is around 8 deg BTDC although with gas (lpg) you will need more advance. mine runs and starts at 14 deg BTDC (lpg) its due to a slower flame front.
however, if you have carbs, you need to ensure that they are dry of petrol before switching over to lpg otherwise the engine will flood, with the coughing etc you have experienced.sorrry if you know this already. just a thought.

[RRV80]

yeah thats what i do, , turn the switch to neutral, wait for it to miss and cough as it runs out of petty ans then switch to gas?

Thanks again, ill give it all a go today.

[RRV80]

turns out i had a wire off on the cutoff solenoid so it wasnt cutting off properly, and i adjusted the flow and now it runs sweet, thanks guys, i wouldnt have had a clue about adjusting the flow.