Mystery problem

[Pete7]

Mk1, thick stubby type are normally the best.

[Cookee]

Every fuel bulb I've ever come across will pump air and fuel - never had to use my thumb!

[DJL]

Originally Posted by Cookee

Every fuel bulb I've ever come across will pump air and fuel - never had to use my thumb!

I agree.

I use one regularly (or not so regularly as the neighbours might say) to pump fuel from the boat into the lawnmower. That always pumps air and self primes.

[Hensh]

Originally Posted by DJL

I agree.

I use one regularly (or not so regularly as the neighbours might say) to pump fuel from the boat into the lawnmower. That always pumps air and self primes.

Priming bulbs will suck air and there is no need for bleeding the system on carb models as the carb float chambers will do that for you. Even the the injection engines are self perging.

[timw]

Many thanks for your replies...but the mystery deepens.

Despite the engine being able to idle, underload it cuts out.

However, on linking the engine up to a portable tank, it runs fine.

We have changed the bulb as well.

So the problem appears to be that the engine is unable to draw fuel from the main tank.


I guess this may be something to do with fuel lines / breathers. Everything visible looks OK, but there is no inspection hatch to look at the tank

I suppose we will have to cut a hole and make a hatch to have a look at it.

[jwalker]

Does the fuel come up the pipe to the engine easily? If not, work down the piping, opening it at each connection, and try again. If you find that the blockage is in the tank section and you are unable to suck it clear, then blow it back into the tank. It could be that it will never recur.... then again, it may. However, it's a bit less drastic than attacking the floor and opening the tank.

[jyasaki]

Originally Posted by timw

Despite the engine being able to idle, underload it cuts out.

However, on linking the engine up to a portable tank, it runs fine.

Sounds like it *could* be the fuel pump in the engine (unlikely, though, if it runs fine on the portable.)

One thing to try is to leave the filler cap open a bit to bypass your breather tube.

Does the fuel bulb on the primary system collapse when you're running? If so, it points more to fuel line clog.

Oh, and you might want to change out the filters again (I'm assuming you've got a cannister type filter in-line somewhere.) The on-engine fuel filter should be relatively cheap.

Luck;

jky