HELP me solve my popping webers problem

[jumpinjimmy]

I'm trying to resolve an issue with my poor running 1970 911 2.2 litre with Webers. I suspect it is the Marelli distributor but would like some other opinions. I've successfully adjusted Webers before so feel comfortable in dismantling them and checking them over. I've checked the float levels with a gauge and they seem ok. I also checked the amount of gasoline the jets are pumping and that's all adjusted ok. But when I check the timing, at 900 rpms, the advance is about halfway between TDC and 36 degrees, which seems really too advanced (would that be 15 degrees BTDC?). I can't get it to adjust any lower. I removed the distrib. cap from the Marelli and the counterweights seem really floppy and loose. I'm not sure how much free movement they should have before the springs do their job, but they seem to move too freely. Could this be causing my carbs to pop and splutter constantly, especially when warmed up? Especially at lower revs.

Also, I want to do a valve adjust but there is no mark on the marelli to align for the number one cylinder. any ideas on how to proceed?

Any help you can offer would be greatly appreciated.

Steve

[chris68]

Hi Steve,

I spent a long time trying to cure popping Webers on my 2.0 lite car and eventually realised that most of the problem was due to incorrect timing and a poor advance curve.

If the timing is good, popping back through the Webers is a sign of an overly weak mixture. Check the idle jets aren't blocked and also that they're aren't any air leaks. Leakage past worn spindle bushes is particular problem. Check by feeling for play where the spindle exits each carburretor bank.

Again, I'd make sure the timing is correct through the rev range before trying to adjust the carburretors. PM me your email and I'll send you a step by step guide for correctly setting up the Webers.

Best of luck.

Chris

[Joe Bob]

Consider swapping the Marrelli out for a Bosch. Parts for the Marrelli are few and expensive.

[jumpinjimmy]

I took out the marelli and checked it over, did static timing, readjusted carbs and no longer popping and running really pretty good! but I'm going to have the carbs fine tuned by a pro on wednesday. Thanks for your help!