Fuel pump

Post by **britab1967** » Tue May 12, 2009 11:29 am

Probably not much help but I've got an inline filter in mine. Sometimes before I turn the key the filter will be empty and then it will rapidly fill up. You will then be able to see the filter slowly filling with regular ticks, so sounds right to me.

That's what I expected, but it isn't what's happening. Turn on the key and it pumps a tiny amount into the filter and then stops.

BMC
Yes we cleaned out the pump filter. When we stopped on the road it was full of rust so we took the bottom end off the pump and totally cleaned it out.
The pump runs sweet until it gets fuel into it and then it almost totally stops. I will try and lightly oil the pivot points for the contact mechanism.
I can't think what else could cause the problem, after all it is only a solenoid mechanism with a spring return.

Brian

Post by **kennatt** » Tue May 12, 2009 12:10 pm

The only way to check the flow is to take off the pipe at the carb and see how much is being pushed through into a container, There should be a steady strong pulse of fuel for each tick of the pump,I think somewhere in the manual tells you how much flow per minute with a funtioning pump.If the carb bowl is full then there should be no flow although the pump will still tick in standby mode,so looking at an inline filter will tell you very little about the state of the pump.

Post by **britab1967** » Tue May 12, 2009 1:04 pm

Thanks Kennatt

So, in effect, the diaphram stops working due to the back pressure against the closed float valve, when the valve opens, it allows fuel to flow again. "Standby mode" being where the energised coil cannot overcome the backpressure against the diaphram. (That's how it makes sense in my head anyway)

I will try with the outlet disconnected.

I will also try lubricating the original pump contacts as that looked to be a newer pump.

Brian

Post by **bmcecosse** » Tue May 12, 2009 10:24 pm

The pump is supposed to stop when the float valve shuts! Problem with extra filter - if it's mounted above the carb - is that when you switch off that fuel will slowly drain down into the carb and be lost. On restart - the pump has to refill the filter. Just seems a waste of expensive fuel!