Fuel consumption and flow rate

[andrew honychurch]

Wow, some great in put here thanks Guys. David, as you know I have pretty much copied your set up with the electric pump for all the reasons I highlighted above, and a pressure regulator with filter. Previous to getting the tanks resinstalled and making up new fuel pipes, I was running it on a Jerry Can with a small electric pump on the top. Made as a "get me home for the DUKW, if I got fuel pump/tank/line problems whilst at sea. I didnt fancy gradually sinking as I tried to get to grips with where the problem lay, sorry I digress. On the Jerry can the Carrier ran well with no overfueling problems but it did feel odd at higher revs. Almost as thoughyou had to keep accelerating to maintain steady engine revs. I did wonder whether the main jet was blocked and it was only working on the power jet and accelerator jet, but since it is a brand new Carb and really perfect, I dont think it is that. This led me to think that the electric pump on the Jerry can was perhaps not producing the flow necessary and therefore after accelerating there was a momentary loss of fuel requiring a few miliseconds to recharge.

Anyway, without getting to the bottom of that problem I have now fitting all new, copper, fuel line, new original specification "junior" fuel filter and as already mentioned the electric "facet" and fuel regulator. I too , have set this at 3.5 psi.

If the pump is left on for too long without starting the engine, it will overcome the carburettor float valve and flood. It may well be that the engine was designed to receive fuel at this pressure but of course the advantage of a mechanical pump is that it will not pump unless the engine is turning over, unlike the electric one.

I do worry that I may have too much head for the pump to manage to keep up with when the engine is running. In other words, yes it will flood when the engine is not turning over, but MAYBE as the pump and filterking are mounted high up it cannot keep up when engine is running? I have mounted the pump about the same height as the carburettor which is about 3 feet above the bottom of the fuel tank, which in turn is about six inches higher than the original fuel pump.

On the fuel return pipes, I fully get the advantage of returning unspent fuel to the tank, and have long been told that this will help remove the vapour locks back to the tank. However, since there is no obvious way to achive this without creating new pipes into the two fuel tanks ( or just one I suppose) I have left this alone. The Filter King advertises that it is able to negate the effects of vapourisation in its design.

http://www.demon-tweeks.co.uk/perfor...tor-and-filter

I am sure I am somewhere near achieving correct running but as Lynn says, it could be as simple as a vacuum leak somewhere or even a fault with the Governor. More digging is needed, and its stopped raining here in Kent, so I am off to play now. thanks chaps

[Lynn Eades]

Is your pump too high in relation to the tank?
Some pumps are good at pushing , but not lifting.
BTW Jerry cans are notorious for flaking paint on the inside.
Don't let it flood. It will bore wash the lube from the rings in your new motor.
just more thoughts.

[andrew honychurch]

Hi Lynn, the pump is about 0.2 metres above the bottom of the fuel tank, and looking at the Facet cylinder pump data, they will work at 0.3m so I think I am ok as far as that is concerned.

Anyway, I have just taken it out for a couple of miles across country. BLOOMIN FANTASTIC. she ran really well, and the electric pump and regulator seems, as David Gordon agreed, to have ironed out the idling and smooths out the performance. Not discernable flat spots and its getting better and better. Really pleased. The only bad news is its tracks have now got muddy!!

I am going to try to get one of my daughters to do a proper video in the next few days and I will get it posted up to YouTube. I think that the fuel problems may be solved thanks to me having a couple of lose fittings on the new pipes. As many are double flared fittings, they needed to bed down and then get another pinch on the pipe nuts. Fingers crossed. I defintely think it is not doing more than 3 or 4 mpg though! What a fun way to convert cash into hot gases though.

[Phil Waterman]

One more comment on electric pumps and ethanol I would add. I have had problems with electric pumps seizing or working poorly once they have had ethanol gas run through them and then have been allowed to stand open to the air dry.

Discovered this on test stand running in engines once used if the fuel pump was allowed to stand dry they failed. Had two of them do this in a row fortunately this happened both times with in a month of buying the pump and the auto parts store took them back. Now when I disconnect an pump from the engine or from the tank I make sure that the line and pump stay full of gas.

Just a thought.

Cheers Phil

[andrew honychurch]

thanks Phil, I will bear that in mind. Although the pump I have used is an oldish one, its the same as the current Facet offering, and therefore a new one will bolt straight on to my installation. I would assume, that the current Facet range has been designed to take Ethanol fuels???

[Phil Waterman]

Hi Andrew

Should be but not necessarily, both the pumps that failed on me were bought long after we went over to Ethanol 10 gas in the US, like two years. But there is no way of knowing how long they had been sitting on the shelf in the auto parts system. Both of mine were I believe Carter brand.

Got to buy another this week for installation in my HUP so I'll check if they are marked as OK for Ethanol.

As to replacement diaphragms to rebuild old carburetors as has been mentioned. Ones being sold by outfits like MACs are probably good. But I've seen some being sold elsewhere that are single layer diaphragms which I don't really trust. Have one in my spares box in one of the trucks that still has a manual pump. Figure it would at-least get me home.

Cheers Phil

[andrew honychurch]

thanks Phil, I will bear that all in mind. I feel sure that the electric pump system is the way to go with all the changes to modern fuels and the ethanol issues. I will know soon enough if I have problems with the pump, I will of course report back here. thanks