Carb issues take two, Idle still dropping off Dual IDF 40s Options

[VaccaRabite]

If you remember from my last thread, I have started having an issue where my idle was dropping from 1100 to ~500 and the engine would sputter. I thought it was due to clogged idle jets.

Well, Friday I cleaned the dickens out of my idle circuits and set idle back to 1100. Yesterday (saturday) I drove the 914 70 miles to Plaskets' summer BBQ. The car did great until I got to within a few miles of Plaskets, with the idle falling off again. ScottyB and I tinkered with it for a while - checking timing and trying to figure out what the hell was going on.

What we found was that the drivers side bank of carbs was dropping out, possibly due to the idle stop backing off. But the carbs were just being wonky. We ended up not really fixing anything. I set idle back to 1100 and headed for home. the 70 mile trip was more or less uneventful until I for a mile or so away from my house. Stopped at a light and almost home, I could feel a cylinder drop off. The idle dropped down to about 1000 rpm and the idle became just a little lumpy. When I got home, I was back to idling on 2 cylinders at 500rpm and the car was sputtering in my driveway while I waited for the garage door to open. I had to keep blipping the throttle to keep it alive.

The thing is, as son as you give the car gas, all four cylinders fire up and the car is a blast to drive. Its just back down to idle where I have issues.

I am at the point where I am going to unhook the linkage and start from scratch to rebalance everything, and hope that fixes it.

If anyone has other ideas as to what is going on I'd love to hear them!

Zach

[jmill]

Even with the idle stop screw backing out you wouldn't drop a cylinder. You'd just close the butterfly all the way giving you a really low idle. Dropping a cylinder means you fouled a plug or have a plugged idle jet.

Getting a better filter and running one at each carb and one at the tank should catch the gunk. Your 1100 idle is a bit high. Even with a healthy cam you should be able to get it lower. Dual carbs smooth out lumpy cams.

Instead of investing in smaller jets, turn in the idle mixture screws a bit. It wont affect the volume through the progression ports but you'll have less flowing out of the idle mixture screw port. It'll lean up your idle a bit.