Board logo

too much fuel
phil m - 9/12/06 at 01:02 PM

Just been primimg the engine with the new side draughts on a x-flow.

Plenty of petrol reaching the cylinders, but I.m getting overflow from the forward carb out of the trumpets. Float level seems ok -- any ideas

Phil

ecosse - 9/12/06 at 01:25 PM

Stuck needle valve maybe?


Cheers

Alex

phil m - 9/12/06 at 01:32 PM

that seems ok , thanks. Still on the mechanical pump aswell

02GF74 - 9/12/06 at 01:36 PM

quote:
Originally posted by ecosse
Stuck needle valve maybe?



or dirt preventing the valve from closing or a holef float.

you can put carbss on a bench then connect a fule line, funnel on the end, pour in petrol and if it is coming out of the carb, then need to look at the fuel meterining = float/needle vavle.

needle valce - this could have a brass point or a viton (rubber type of point). if former, and has a wear grrove, you can polish it out - put in drill and apply fine enery cloth - it may work but if it doesn;t the needled is throw away anyway.

use a ear bud or similar for the valce seat; I have in the past made a cone from fine amery clother and gave a couple of turns - to clean the face up - didnp't do any harm.

Peteff - 9/12/06 at 02:00 PM

Have you got a return line, the pump will not cut off when the float is full and could be beating the valve.

phil m - 9/12/06 at 02:16 PM

I don't have a return- and I wondered aout this , but I'm sure on another thread it wasn't clear about the need for oe with side draughts - it dose make a lot of sense though-- is it definitive to have a return on this type of set up ?????

Peteff - 9/12/06 at 02:35 PM

Stick tour thumb over the end of the pipe and see if you can stop the fuel flow with the engine turning over on the key. From an article on Triumph tuning:-
Webers need lots of fuel flow but can't stand pressures over about 5psi (3-4psi is a good number). The shiny-toy pressure regulators sold in discount stores cannot flow enough fuel to keep three big float bowls full at high engine speed, unless you use one per carb. An unregulated stock fuel pump will put out up to 8psi at hi-rpm which will sink the floats, causing other problems.

[Edited on 9/12/06 by Peteff]

phil m - 9/12/06 at 04:23 PM

done the thumb test - stops flow, I,ll have another go and see waht happens -thanks for the replies

madteg - 9/12/06 at 06:51 PM

throtle pump jet seats leaking. I had this on mine, was dripping when engine had bean run then stopped, dripping out of front of the choke.