carb popping 6 this time, everybody loves carb threads Options

[dem]

Drove the 914 to turkey time yesterday, about 50 miles of backroads. Seemed to be runnin' about normal with the usual symphony of only-occasional random backfires and pops. It was, of course, ridiculously fun.

Car sat til I left around 10 PM, and by then it was around 40 degrees outside. Lots of popping and stuttering at part throttle. Full throttle and it was the usual fun excitement.

The ride home on the freeway was unpleasant because the 2.7L doesn't need much throttle to keep my little car moving. Could this just be temperature related? Idle jets sized for Los Angeles (where I bought it.)?

Otherwise I assume I'm looking at checking for gunk in the idle jets, I assume.

This is my first carbed porsche, so I guess it is time to really "grok" them. Is there an obvious "start here carb newbie" direction? Book and/or web site? Googling turns up tons and tons of random stuff.

Thanks.

[john rogers]

You seem to be getting on the right track. Several things to consider to help with carbs that were never made to use the gas we try to suck through them now: First is to drive the car every few days and get it hot so the carbs will keep clean. Otherwise you'll get that snot stuff inside. Noew even race gas can develop that stuff if allowed to sit. Next to to use some Marvel Mystery Oil now and then to add some lube and help keep them clean. Next is to make sure there are no air leaks such as base gaskets, insulator blocks, cracks in the intake manifolds (especially if they have been ported and modified) and as you saw those pesky o-rings. If one cylinder seems off from all the others when you are adjusting or checking then there is something wrong, usually an air leak. Finally budget the cost every 2 to 3 years to have the folks at Pierce Manifolds do a full blown overhaul which is not cheap but they will be like fine running Rolex watches when they get done!

If you have radical cams such as 908s or other wild high revving grinds, the carbs will pop and thet is due to the wild cam overlap that is used. To cure this many race cars will idle at 1200 to 1400 RPMs which while irritating on a street car is okay for a racer.