No fuel getting to carburettor/ fuel pump problems.

[tynelord1969]

Hi there,

I've spent quite a few days trying to get my '75 Viva Deluxe 1256 started.
This is the situation with the car:
The car has been hardly used for the last few years but I try and start it up and drive it around my estate every few weeks. What I've noticed over the years is that if the car isn't started for a more than about 2 weeks, I sometimes have to squirt petrol into the air inlet area of the carburettor ( after removing the air filter housing and lifting up the piston of the Stromberg carb) about half a dozen times and keep turning the ignition on until it finally starts. Sometimes when the car is fully warmed up and I stall it by accident or try and start it after parking it up for a short while, it won't start at all ( as if there is no petrol). Eventually it starts up so I wonder if it's fuel vapourisation. I've had the car for 29 years and only in the last 5 years has this problem occurred. I was told by another classic car owner that new petrol is rubbish and is prone to vapourisation. I usually put Frost Ethomix additive into the tank to compensate for the change in petrol formualtion. I don't get this problem with my FD VX/4/90.

With the recent problem of the car not starting, I fitted a newer battery from my VX4/90 and checked if fuel was actually getting to the carburettor, which it wasn't ( the car wouldn't start even when using Easy Start spay either). I took off the top of the petrol pump and there was some debris inside but on the carb side and not the fuel tank side of the filter, which was very puzzling.There was petrol inside the fuel pump. On turning the engine over on the starter no petrol came out of the outlet pipe of the fuel pump either( this pump was replaced 6 year's ago and the car has hardly been used). Thinking the pump was at fault I swapped it over for a sealed unit type pump ( the type originally fitted to 1975 cars). On unbolting the old pump I noticed a crack at one of the bolt holes of the pump and the whole side finally cracked completely off after re-bolting it back on again. It seems that the contact surface on the engine seems to be slightly convex so that when the new pump is correctly positioned, there is tiny gap on either side of where the bolts go and I assume this has caused the pump to crack along the bolt hole when it was tightened onto the engine. It was hard to tell if there is a heat insulator but it looked white when I scraped the surface and was less magnetic than the engine block. When I fitted the new pump I didn't tighten it too much in case I cracked that too. Are new heat insulators available and are they simply tapped off to remove the old one, mine doesn't seem to have a flat mating surface anymore? On turning the ignition the engine didn't turn at all on the starter but made a click, so I think the starter motor is now jammed. I tried turning the engine over by using a spanner on the engine pulley to see if petrol was being drawn from the tank, but nothing came out ( there is just over 1/4 of a tank of petrol in). I'm wondering if there is a blockage from the fuel pipe in the petrol tank now.

I tried uploading some pictures to help illustrate the problems but the file sizes are too big unfortunately.

Any suggestions?

[jpsmit]

The click when you start is typically a dead battery not a stuck starter.

In terms of your description, I would suggest you most likely have bad gas - followed by gummed up components (do you have ethonol in the UK?) followed by a blockage somewhere.

The easiest way to start to sort this is to see if you can run the engine from another tank with fresh fuel - I might start with a gravity feed to the carb directly, then through the pump. If it works as gravity feed, the problem is not the carb.

If the pump - not the pump.

you may need to drain the tank and refill (and possibly clean it)

also are there any filters that need top be replaced?

[droopsnoot]

I used to have a similar problem with my Sportshatch, after it was left for some time it would crank over but not start. That was down to the diaphragm in the fuel pump losing strength - I was still using the mechanical pump, and the engine just didn't crank over quickly enough to pull the fuel down from the tank. To get around it I'd do the same - chuck a bit of petrol into one of the carbs, or spray some easy start - or even the other way (which I've since found out can be very dangerous to the health) of taking the pipe off and sucking the fuel down to the pump. Fitting a new mechanical pump cured the problem, but a rebuild kit would probably have done the same.

I wouldn't expect that turning the engine over with a spanner on the crank would do anything towards pulling fuel from the tank, it's just not going quickly enough.

I'm not sure how the heat insulators are sited on the OHV engine. On the OHC, some fuel pumps need a thicker insulator because the actuating arm is longer, and if they are fitted with the wrong one it doesn't get as much movement from the auxiliary shaft - the results are that it works, but not very well. I've also seen the "not flat" mating flange on the OHC pump, but that causes an oil leak rather than poor pump performance. You can either try to file the flange, or modify the heat insulator block (if indeed it has one) to fit snugly.

I have also been told that, with modern petrol, one of the additives that aids starting is also one of the additives that "goes off" quickest. Hence sticking a bit of new petrol in the carb, or starting the car with a pipe directly to a fuel can with new fuel, can get the car running, whereupon it continues to run.

[Fred Dukes]

Ethonolmate is an additive which amongst other things claims to reduce the rate of the fuel going stale
https://www.flexolite.co.uk/item.asp?iID=130

[tynelord1969]

Thanks for the replies. I'm not sure how to reply to each individual.

The click when I last tried to start the car is puzzling as it is a newish battery and was put on charge that day, but I hope it is just gone flat rather than the starter motor.

I think Britain is increasingly adding ethanol to petrol so maybe that's why the car is worse than years ago. So yes I do use ethomix in the fuel tank and had only just put a fresh gallon of petrol of in the tank, which was practically empty. If I only put a gallon or so at a time , I was thinking, that at least there is a better chance of diluting any petrol that has gone off, more effectively.

I see what you mean that trying to turn the engine over with a spanner wouldn't be enough for the pump to draw fuel along the pipes.

Thanks for advice on possible weak diaphragm action of the fuel pump. Even though the car has only done probably a few hundred miles since 2011, I wonder if lack of use has actually caused the diaphragm problem, rather like leaking break cylinders, if the car isn't used for long periods.

I'm wondering whether the cause of the non-flat contact surface of the heat insulating block of the fuel pump mating surface is due to a mechanic trying to remove the old pump in 2011, and he damaged the surface of it. Does anyone know if new heat insulator blocks are available for the OHV engine?

Leon. HC171

[droopsnoot]

I don't know specifically about the OHV engine, but I do see those heat insulators on autojumble stands from time to time, which suggests something else uses a similar idea. They also come in one of the gasket sets, perhaps the bottom end set.

[tynelord1969]

Thanks for the advice about heat insulator blocks coming with a lower end gasket set. I will check to see if I have a set amongst my spares.

[tynelord1969]

Paper gasket over the possible heat insulator block. I couldn't really tell if the insulator block was actually present, but there seemed to be a 1/4" thick spacer ,due to a faint joint line where it is in contact with the engine .

[tynelord1969]

Looking down at the possible insulator block with paper fuel pump gasket.

[tynelord1969]

The existing fuel pump with the cracked bolt fixing hole which I think was caused by the non flat surface on the engine block. The section must have fractured when the pump had been tightened onto the engine.