Cold starting

[skywalker]

Hi all- 1st post on the forum so hi to all. Never had any problems before so im a stranger to this forum!
(Ive been running an LPG 4 litre jeep for 8/9 years still going strong with 110,000miles)

I have a question on my other truck- a Jeep Grand wagoneer with the AMC 360 (5.9 L) engine. I had this one converted over a year ago - Its an Impco kit with the 300 a or 425 unit i think - which fires into the existing 2 barrel carb through a kind of trumpet! -Thats a CT 425 mixer i believe. Swapping it back and forward manually and draining the carb every time is a pain - so i dont bother. I run it 100% on LPG. BUT starting is a little hard especially in minus 2-5 etc. It will always fire but after about 3-5 seconds of cranking. On a good day 0n petrol its virtually instant. The installer (no names mentioned) did a pretty shoddy job on the whole- total mess of cabling / used petrol pipes/ old jubilees that ive been tidying up and fettling ever since. The auto choke carb was still activated so the choke butterfly blocked the path of LPG if engine was cold. (installer insisted starting on gas would be fine) I adjusted this so choke flaps remain open but this only makes a little difference.

So after all that rambling i have a reliable/ very heavy on gas / truck - and the question is ? Is there an enrichment device/ choke device to prime the intake with gas and fire this baby up a little quicker - before my new optima and starter motor go on strike?

PS once fired up no probs whatsoever with icing / stalling - warms up quick and runs like a champ ( just dont like the cranking)
thanks in advance

[jayc]

Depending on your vaporiser (likely an impco model e) you can either fit a primer button actuator or start assist valve.

Also depending on what kind of change over switch is fitted you can flick the ignition a couple of times to fully fill the vaporiser with fuel before starting.

To be honest the start assist valves are only really sold to users in the northern american states and canada and with our temperate climate shouldn't be needed if correctly set up. Both my boats start within 2-3 seconds in the coldest winter temps even if they haven't been runs for weeks.

[SimonHobson]

I'll second jayc's comments - I've run LPG vehicles for some years now ... hmm, well over a decade of V8 on LPG and they said it would never last Apart from the last 2 years when I've had EFI in the 110*, it's all been with carbs and I've been starting on gas. Apart from when the battery is a bit low, I've generally not had a problem and have just primed it a bit more in very cold weather.

Most switches/safety relays intended for carb use will open all the gas valves for a while when you first switch on. This allows you to dump a bit of gas in through the mixer and leave a pool of rich mixture ready to be sucked in and mixed with what's already in the manifold.

* It's still EFI but I haven't had a working petrol pump for a few months so I've set the Leonardo for alternate fuel start and start it on gas. It's struggled a bit in this very cold weather, but that's been down to a battery that's past it's best resulting in insufficient spark - so I've got the hang of spinning it in very short bursts so that when I let go of the key it will fire once the battery voltage recovers and kick over.