Villiers Carb

[Gannet]

On my Villiers carb, the cap to the throttle slide bore (the bit the cable adjuster screws into) has, on the inside, a raised cast 'peg' acting as a stop to the throttle slide. This stop results in the throttle slide, at the max open position, still restricting the air flow, ie it doesn't open fully to clear the main bore. This cast 'peg' is 1/8" long, which is about the same distance that the throttle slide needs to travel to be in its true fully open position.
Is this correct? Does it restrict power output? The engine is an FV, which has not been recently fiddled with.
In my box of bits I have a brass throttle slide bore cap which doesn't have this cast 'peg'.
Why is this stop sometimes provided? Does it depend on the engine spec?
Jeremy '

[Vic]

You dont mean the little peg that locates the top correctly (1974 Featherweight)



cos that doesn't



You mean something more like this ( on a ca 1950 Villers engine)




That does not either



because it slides into this hole

[Gannet]

Thanks Vic, excellent photos. I should have posted a photo instead of trying (and failing) to describe it.
Anyway better late than never - here is a photo. The cast 'peg' as I described it, is to the left of the throttle slide location rod.
Cheers,
Jeremy

[Keith.P]

Looks like a max throttle stop, so you don't get full revs, not seen a seagull with one, either remove the peg or replace the part.
Nice little FV.

[Hugz]

A governor in affect. A special order? Another mystery to solve. Though it could be to reduce airflow to match carb to motor.

[Gannet]

Thanks for your comments.
I have just looked - and I should have done this before- at the carbs on my two other FVs.
Both have this throttle stop. So all three Fvs are the same. This is unlikely to be a coincidence, even though the part is so easily removed. These are relative early/mid FVs - 1786, 1867T and 2682.
Perhaps all FVs (and FVPs?) have this stop?
I wonder why; hopefully one of the experts on this site will comment.
I was wrong to describe it as a cast 'peg'. It is a machined steel (stepped I think) dowel located in a hole in the top cap.
Thanks
Jeremy