I was hoping tha tyou guys could help me with a little problem. When I first purchased my 73- 914 a few years ago, I took out the spark plugs and they looked great. I started driving it myself and now I always have a huge amount of blakc carbon deposits even after only a few minutes of driving. I realize that black deposits normally suggest too rich of mixture however I have not made any changes to the carbs so I cannot figure why this would happen. The only thing that I changed was fuel. I also used 93 octane fuel, not sure what PO used. After this has happened, I have played with the mixture setting on the carbs however I wasn't able to fix the problem.

Could this be from a higher octane fuel? Timing problem? Too cool of plugs?

Engine info-
1.8l case however 2.4l due to new cylinders/pistons...
2.0l heads
msd 6al ignition
bosch 050 dist with pertronix
timing set at 27 degrees at 3000rpms
plugs-autolite with 63 temp, also tried 64 temp, also tried bosch plugs but I dont remember the number
93 octane fuel
plug gap .045 (due to msd ignition)

I clearly do not have a good understanding of plug reading. I have read quite a bit however I cannot figure out an answer to my specific problem. Any ideas would be greatly appreciated.

Thanks,
Steve

dual weber 40idfs

What size ventures do you have, also what jets are you using?

Really...this is a carb issue.
Describe your intake setup.
Carb (s)
Main jets
Idle jets
Air correction jets
Venturis.

Also, camshaft and head flow numbers to be really accurate.
It can be done without those numbers.

What type of driving do you do with the motor??
Street, track, Autox?? A mix of all?

Rich

I will get the settings and sizes when I get home tonight. I use th ecar for a little bit of everything- street, track...

I take it that the higher octane fuel would not be the issue?

not really an issue for running to rich...to much fuel is to much fuel.

Around town you are running on the idle circuit for quite a bit of driving.
The size of the venturis, the size of the intake valve, and the jet sizes are all going to contribute to getting this to work.

The idea is to speed up the intake charge to bring in MORE air...
this require making the venturi/valve smaller, and possibly the idle jet smaller also....

gotta see what you have first.
See if you have the build sheet for the heads and camshaft...it makes a difference.

Rich