Mechanical Fuel Pump & Priming

Mechanical Fuel Pump & Priming

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HustleRussell

Original Poster:

24,724 posts

161 months

Friday 17th July 2020
quotequote all
My Dad and I recently bought a Formula Ford with a Kent engine.

When we bought it the previous owner told me that it was tough to get fuel up to the carb when the car has been sitting for a while. You'd be turning it over for ages flattening the tiny battery waiting for fuel to get up to the carb. He advised removing the air cleaner and squirting some fuel in the top to get it going.

I ran the car at Brands pre-lockdown and sure enough it was a bit of a pain. I didn't like the idea of squirting fuel in the top because I was worried about putting too much in and hosing the bores down, so I duly flattened the battery before resorting to the recommended method.

Once it was going it was on the button all day.

I suppose the issue is that the carb and possibly even the fuel pump are higher than the fuel level in the tank so the fuel drains back over time.

Is it typical to have a check valve in the fuel line to prevent this? If not, how else can I solve it? I can't imagine everyone else with a Kent FF is having to do the same engine start procedure!

HustleRussell

Original Poster:

24,724 posts

161 months

Friday 17th July 2020
quotequote all
Will check the regs but I suspect that if electric fuel pumps were permitted the car would have one

HustleRussell

Original Poster:

24,724 posts

161 months

Friday 17th July 2020
quotequote all
How long do we think it'd take for the fuel in the float bowl to evaporate?

P.S. checked the regs and electric fuel pumps are prohibited

HustleRussell

Original Poster:

24,724 posts

161 months

Saturday 18th July 2020
quotequote all
tapkaJohnD said:
In FF, are you allowed an accessory battery, connected by an Anderson plug?
Then, you can have full size battery for start up, even on the grid, if your crew will bring it.

JOhn
My car does have the Anderson connector. Using a battery tender used to be absolutely necessary and a lot of people still do it... however the little AGM batteries used these days have enough power to start and run the car all weekend with little or no topping up provided the engine is able to start promptly.

I’m not going to have a crew so I will be making do without a battery tender.

It would help if even for the first start of the weekend but the car is taking so long to start due to the fuel drain back / evaporation issue that I’d want to rectify it for the sake of the starter motor and wiring as much as the battery. I think the starter motor is an inertia type as well but I’ll need to check that.

Currently thinking that I need to make sure there’s no way for air to get into the fuel lines upstream of the pump but apart from that I’m not sure what I can do... I’ve gone off the idea of a non return valve a bit because it’s an extra thing to go wrong and two extra joins in the fuel line...

I think I need to find out if this is an issue which will manifest overnight or whether it’s only when the car isn’t run for weeks because if it’s the latter I’ll probably just work around it like the previous owner did- get the car running in the workshop before I set off for the weekend and / or squirty bottle of fuel.