Thread: Fuel pump pulse type

Originally Posted by blip

Cool thanks for the info. The pump im refering to gets a vacuume or pressure pulse from the engine that operates a diaphram that pumps the fuel. It seems to work if I lightly suck and blow on the pulse line.

Yep, lightly suck on vacuum line. Not too hard, it’s only a light spring. If diaphragm has gone a bit hard it will pump but at a reduced volume. Make sure hose is tight on fittings. Pump kits are cheap as if needed. As said before, check valve clearances, they can be fussy little fuckers those engines. Good luck.

Exactly right, they can start being a pain in the arse with very little notice or warning - and then you might not find out what was causing the issue after the third time checking everything out and the damn thing starts running like nothing was ever wrong!!!

Having the aftermarket work that you'e listed on yours, I am going down the fateful track of assuming that the valve clearances, head condition, rings, cylinder are all good and obvious things like the spark plug and magneto/kill switch setup aren't playing stupid games.

I haven't seen one of these with a factory pulse take off as the factory carby relies on gravity feed to the fuel bowl, but the logic in tapping the governor rod hole and using that is sound. That should provide enough fuel to get the thing running right, but then again... A possibility is a marine style primer bulb in the fuel line, a couple of pumps before starting to get enough fuel in to get the thing ticking over?

Its a bit of a learing curve which is half the fun. I just prime it by blowing on the fuel tank breather