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Fuel pump, poor starting


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Just thinking about jobs for this year......hopefully tweaks now rather than major overhauling.

one thing I’ve mentioned before is since adding a glass fuel filter it takes A LOT of cranking to get the engine to fire after it has been stood for a week or more. When I say a lot if you add the bouts of cranking it would be 45-60 seconds. It was mentioned that it could be the pump, still original mechanical. Should I bypass the filter to see if that improves. If not would it indicate the pump is on the way out. Should I disconnect the outlet and see if there is a flow so possibly indicating an issue at the carbs.

rather than post 4 questions under each area hopefully you don’t mind off topic questions under one post.

slight weep from the thermostat housing so will fit one of those thicker gaskets I got from the club shop.

Going to try to fit the occasional rear seats. If anyone has got a template for the seat bracket that would be very helpful.

might change brake fluid to silicon, do you need to wash out the system or can you just displace the old dot 4 with the silicon?



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Its the fuel in the float chambers evaporating that causes the need to wait while the pump refills them

Nothing to do with the pump any idea its drain back  cannot suck fuel back out of  the float chambers

Both my vit6 and the 2000 need a good few pumps on the hand primer , you can hear the fuel loading the float chambers

This is a trait of carbs that has been there since time began, the float chamber is vented so your magic juice escapes to the clouds 

Electric pump wins as it primes as soon as turned on, 

Without a hand primer your in for some cranking



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As Pete says the float chambers do slowly empty themselves but that cranking time is rather long to refill even completely ones. The mechanical pump has two non return valves in it and if either one doesnt seal well the pump loses effectiveness and its pumping flow rate is reduced which can also cause fuel starvation during high speed runs. The only way I know of testing the valves is by removing the pump filter cover and then sucking on the inlet and blowing through the outlet connections neither of which should allow air to pass.....

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Silicon is a crystalline structure from which transistors are made.  Silicone is what you need for brake fluid. :lol:  It doesn't mix with Dot 4 and the transition is done by pumping it in until what comes out is purple, the colour of silicone. Worth reading this before you decide.



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Trust you Doug, I’m a geologist so I think in silicon rather than silicone! I’ll have a read of the link. I have got a primer and it takes an age, again over a minute of rapid pumping. I feel it’s not sucking enough but not based on any comparison. I take the point on evaporative loss but how long does it normally take to refill them?

failing that it’s a length of tube for sucking and blowing.

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