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Tue Nov 03, 2009 9:50 am

I have just been trying to set the fast idle throttle gap on my PDSIT's. (For a 2L camper) and am a bit confused as to where the choke should be when setting this gap.
Benson says :set with choke valve fully closed" would this be in position A or B in the pictures below?

Thanks

Tue Nov 03, 2009 9:57 am

Who is Benson?

The choke appears to be in the same position in both pictures, what does that cam do when you close the choke plate in the top of the carb? (AKA strangler in your country :wink: )

Photo A shows the fast idle cam at it's highest setting, pic B shows it one notch away from max, niether show it at warm idle position.

Tue Nov 03, 2009 12:01 pm

Thanks for the reply, this might have something to do with why I'm confused about the choke/fast idle link and gap setting.

As far as I know position A is with the choke plate in its fully closed position (do I now set the fast idle throttle gap to 0.6mm? does this position give about 1900 to 2000 RPM?)

Once started the engine vac pulls the cam down to position B (should RPM be about 1300 to 1400)

As the choke coil warms it gradually allows the cam to rotate dropping down each step of the cam in turn, so as the engine warms the amount of choke/fast idle reduces. Until finally the cam does not hold the throttle plate open (via the fast idle link) at all and the idle is about 1000 with the engine nice and warm.

So I guess you set the fast idle throttle gap of 0.6mm when its on the highest i.e. fully closed choke plate, setting?

As to Benson, he wrote one on my university physics text books, I assume he is no relation to Bentley who didn't... and who I obviously meant to quote, apart from a moment of deranged madness!!!

Thanks again for you patience as I am definitely still very much a learner

Tue Nov 03, 2009 12:44 pm

The cam shouldn't move until the choke has opened a bit and you touch the throttle, because of that fine spring between the cam and black choke lever the choke can fully open and the cam will not move.
But anyways, yes, set the high idle gap with the cam in position A (the highest step), the rest works itself out automatically.