Engine Trouble Petrol / LPG

Sorry can't help but had same thing with our Talbot of yesteryear, ran sweet as a nut on LPG but like a dog on petrol. Had the carburetor stripped twice and all was well for a short time then it would run poorly again. Eventually just used to run it on LPG with a comprehensive list of LPG pumps on route, unfortunately, it ruled out some parts of GB.

Good luck.
 
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The only difference appears to be when you switch it over to Petrol. If the engine is not running very well is it getting enough fuel. Normally the fuel is flowing happily through the carb. On yours the fuel is sitting in a hot engine so evaporates as fuel does and could be leaving a deposit behind in the jets. The engine is probably getting just enough fuel to run but that’s about it or it could be the fuel tap not open fully. Perhaps you should look at what you do when you switch over. The outboard we had could be a pig to start if left with fuel in the carb so I just let it run with the fuel switched off until it stopped.
 
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QFour said:
The only difference appears to be when you switch it over to Petrol. If the engine is not running very well is it getting enough fuel. Normally the fuel is flowing happily through the carb. On yours the fuel is sitting in a hot engine so evaporates as fuel does and could be leaving a deposit behind in the jets. The engine is probably getting just enough fuel to run but that’s about it or it could be the fuel tap not open fully. Perhaps you should look at what you do when you switch over. The outboard we had could be a pig to start if left with fuel in the carb so I just let it run with the fuel switched off until it stopped.
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Thats what you are ment to do with outboards engines,no one ever reads the hand book. :unsure:
 
QFour said:
The only difference appears to be when you switch it over to Petrol. If the engine is not running very well is it getting enough fuel. Normally the fuel is flowing happily through the carb. On yours the fuel is sitting in a hot engine so evaporates as fuel does and could be leaving a deposit behind in the jets. The engine is probably getting just enough fuel to run but that’s about it or it could be the fuel tap not open fully. Perhaps you should look at what you do when you switch over. The outboard we had could be a pig to start if left with fuel in the carb so I just let it run with the fuel switched off until it stopped.
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Interesting thanks
OK well the chap who fitted the LPG was super knowledgeable. He said he tested the Petrol switchover and it was fine.
I also tested it once on idle shortly after LPG fitted and it was fine so this is what is happening now:
On cold the engine does not seem to start on Petrol but only tested that once
When warm and running at say 30mph and switched over seems sluggish on Petrol
When warm and idle stopped it is sounding fine on both fuels.
Thanks all for your input and time, much appreciated 👍👍
 
Blocked main jet due to petrol laying in float chamber,remove jet and soak in carb cleaner,blow through and look through,if clear spray carb cleaner in jet hole then refit jet.
Some times i get carbs so blocked on outboards i have to replace them,van/car engines are no different.
 
Lpgs do tend to eat plugs and whilst fine for lpg they may be not be good enough for petrol. Change them first. If no better drive it on petrol for a while and then stop the engine. Take out the plugs and the colour of them will tell you if it is running rich or weak. Coffee colour Ok. Whiteish running weak. Blackish running rich and take it from there. Black take the air filter out and try that. White blocked fuel filter faulty fuel pump, blocked jets or depending on carb split diaphragm.
 
HAVE YOU TRIED REMOVING THE FUEL CAP INCASE ITS A CHOKED BREATHER ,JUST ANOTHER THOUGHT
 
trevskoda said:
Blocked main jet due to petrol laying in float chamber,remove jet and soak in carb cleaner,blow through and look through,if clear spray carb cleaner in jet hole then refit jet.
Some times i get carbs so blocked on outboards i have to replace them,van/car engines are no different.
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Yes I have had to replace a couple of carburetors because I have left petrol in them on a lawnmower and a petrol generator. :(
 
trevskoda said:
Thats what you are ment to do with outboards engines,no one ever reads the hand book. :unsure:
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And chainsaws, and my Honda 125, and my mower, and everything else that runs on crappy ethanol petrol. 6 weeks and no use it will be trouble to start.
 
You should always start on petrol and switch to LPG, it prevents the petrol sitting in the carburettor and gumming up jets, I suggest you take the main jet out and clean it with carb cleaner.
 
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Petes said:
You should always start on petrol and switch to LPG, it prevents the petrol sitting in the carburettor and gumming up jets, I suggest you take the main jet out and clean it with carb cleaner.
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The Gas engineer did not mention that. I am in touch with him and will run it past him.
Thanks
 
I never had an LPG vehicle that didn't start on petrol and automatically switch over to gas. I know FLT's start without petrol but they are often inside and do struggle a bit to start if left out in the cold.
Anybody else had a direct to LPG running setup?
 
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Private said:
I never had an LPG vehicle that didn't start on petrol and automatically switch over to gas. I know FLT's start without petrol but they are often inside and do struggle a bit to start if left out in the cold.
Anybody else had a direct to LPG running setup?
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The LPG on the Van is a manual switch over....just to let you know. Thanks
 
Ah. Any reason why?
My L plated (year 2000?) car was auto switchover as was my latest.
They started on petrol and only changed over to LPG when the engine coolant had warmed the gas enough to help it vaporise. I guess it also helped with lubrication having some petrol use each start.
Is manual changeover a more modern approach as in it doesn't require petrol to start?
 
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Private said:
Ah. Any reason why?
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Reason would be that it is an old Petrol engine circa 1987 with a carburetor system and not a modern injection system.
This is what the LPG Mechanic has said:
There's no real need to start on petrol, if it's something you want to try then the best way to do it is to switch to petrol before you stop for the night otherwise you'll probably flatten your battery trying to start it with an empty carb every time... Especially if its cold up there. All of the modern injection systems start on petrol automatically then they go through the warm up stage before switching over to gas, but they do it all automatically

Thanks for your input (y)
 
Yes, my car does it all automatically; although I can switch the gas off if I want to, I can't turn the petrol off.
 
Yes of course its a carburettor so the only way to switch over is to run it out of petrol, hadnt though of that.
I asume the mechanical pump has been replaced with an electrical fuel pump? If it is stil the mechanical one then there must be a cut off valve fitted to the fuel line. I wonder if the fuel pump is beginning to fail as it will have been working against a large back pressure and is wearing out and as such its not now pumping enough fuel through

All my lpg vehicles have been fuel injected so they start on lpg automatically until the gas is warm.

You could still have a blocked jet as any residue of petrol will be evaporated off once the petrol runs out by the heat of the engine but I would check the pump first.
 
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