Single IDF weber

RJM · tinkerer Joined: 10 Oct 2001 Posts: 109

Has anyone tried to run a single 40mm IDF weber on a g200,
if so what size jets etc did you end up using?

With 115 main jets its way to lean, dies after 3000rpm.

Any ideas on setting up the jetting?

Mooch · backyard mechanic Joined: 17 Oct 2001 Posts: 573

what manifold are u running? did u have to swap for a remote brake res.? or does it fit. (assuming it's not a tx.)

RJM · tinkerer Joined: 10 Oct 2001 Posts: 109

Ported stock manifold, made up a adapter out of a cast aluminum box.
Its a TG.
It fits, the filter rubs a bit on the hood but it closes ok.

Are you familiar with this sort of setup?

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

I haven't tried your particular carb/setup, but first off, are you sure it leans out?

Have you pulled plugs, used an oxy sensor, etc?

Is it a sudden die, or a gradual diminish of power as revs climb?

What was the carb off when using the 115 main jets?

If its a similar engine, then it cant be far off, you just have to go up slightly (or down). It may be too rich if it has small air correctors.

Ben Wight

RJM · tinkerer Joined: 10 Oct 2001 Posts: 109

Yeah its got 115 main jets, 28mm venturies.
Have used a colour tune to see whats happening in the cyliner.
Ie Blue is just right, yellow is rich and white/misfire/engine stops is too lean. At the moment
even with the mixture screw wound in the revs pick up and the mixture looks correct but after about 3000rpm under load it dies (doesn't stall just no power).

I can't get it to go yellow (rich) even on idle.

Are you running a weber/holley carb manual secondary type carby if so what are you jet sizes?
I think a holley 180 is like primary 145 secondary 150 or something but not sure?
Any any ideas as that might help me out!

(Thanks for the reply)

Ben Wight · backyard mechanic Joined: 04 Oct 2001 Posts: 946

I've run a few different webers before, the Holley (weber DGV) has 140's as both main jets, with 165 and 175 air correctors for the primary and secondary circuits respectively.

Check what air correctors you have, they may be too big. You should be able to get a rich idle by turning out the idle mixture screw all the way, if it doesn't start running really crappy (even stall) with it wound out, then either the idle circuit is too small, or the carb is blocked up with crap.

If you have a 150ish air corrector, then I would assume you need a larger main jet, at least arond 130ish.

Explain further the loss of power, after 3000, is it like someone turns off the ignition key, or does it rev higher, just slowly.

Ben Wight

RJM · tinkerer Joined: 10 Oct 2001 Posts: 109

After 3000rpm it flatspots and the car slows down but then engine doesn't stall.

If I floor it fast then sometimes it will fire out the air cleaner, like its way to lean. The revs drop until you back off the throttle.

GasGem · backyard mechanic Joined: 05 Nov 2001 Posts: 755

Check your venturi this happened to me several times, inside your venturi is a small brass tube with a slot in it, this comes loose and due to the slot making it lighter on that side it rotates until the slot points up, and it needs to point down if you are going to get the fuel into the engine, and rev, this may be your problem,

cheers