So after getting the 69 350 to run well without that infamous timed miss after a carb rebuild, another issue cropped up.

The Gas pedal began to get really stiff and notchy. It became like a on off switch. No fun at all to drive the car, in fact pretty much undrivable.

I also ended up with a strange issue. The engine would idle fine but would not idle down, no miss, but the idle adjustment screw was not contacting the idle step cam at all. So no idle down and no fast idle.

Randy had given me the original carb to the car, which currently has a replacement Rochester carb, which I believe is a Frankenstein of sorts. Some Rochester, some china, who knows.

Ok, so now we pull it apart once again. Taking a good look at the throttle action, it is binding a bit...and the plates do not close in the bore. So the idle can never drop below a fixed point as there is air passing by the idle bleeds.

You can see the light around the plates especially at the screw sides,

So I'd cleaned up the original to the car 2GV base hoping to use it.

Assembled, the shafts are almost perfect, and the blades actually shut much more precisely in the bores. Almost perfectly at the screws. I'd call it very good condition. Way better than the whatever base.

So I put the carb back together with the better (original) base, hook it all back up and I now have idle authority, and the initial tip in is not bound at all. But at partial and adding gas at speed on the road, the pedal is still sticking bad.

Back in the drive now thinking... I've been asking myself is this binding the accelerator pump? Could be. When I first set up the pump rod, as found it was bent very long, in fact the measurement from the horn to the top of the rod (see diagram) was way short, like 3/4". The specs call for 1 13/32" so that is where I set it thinking this was the way to go. Maybe now I should try to go back to where it originally was?

So I pulled the rod, made it longer and put it back in place. Doing this effectively moves the pump piston down the bore a little more, and swings that green lever up into a position that is clearly easier for the throttle arm to push up.

Went for a drive. Perfectly smooth pedal! I'm thrilled! It feels like a different car. I'm in love again... So much so I set the timing and played with the screws. Runs like a new 350. FINALLY! 

I think the rod was binding trying to overcome that straighter push on the green pump lever. When all new, it might not have mattered, but on a old carb the shaft on that green lever into the carb lid is pretty worn. I think an older lever must sit around the 4 o'clock position (like in the image). To spec it's closer to 6. Drivability is great now, no delay or hesitation, seems more powerful even. Ignore the spec for this on a old carb. You need to have the lever preloaded some at idle.

Heres a link to bushing the pump lever hole, 

-- Edited by cdnpont on Thursday 9th of May 2024 08:24:32 PM