fouling plugs

[87Sprint]

this is a bit of a newbie question but i serviced my car the other day and notced that the plugs had a reasonable amount of carbon buildup - which is supposed to mean a overly rich fuel mixture right? the car runs great and i have heard that carbs are sort of a compromise between smooth running at low revs and smooth running at high revs - is this true? - does this then foul up the plugs if im just pottering around town and its set towards running better at the top end of things? should i get it tuned or am i just being twit?

btw im going to classic adelaide in a minuete so if i take some snaps of some alfas (and im sure i will) ill post em up

[Eddie W]

Hi, because of the twin carb setup it is not unusual for the plugs to show rich in stop/ start running, however if you have Dellortos then it would be advisable to check the float weights as they become heavier over the years leading to a gradual enrichment. This is inclined to creep up almost unnoticed and as the boxer seems to be very tolerant of over rich mixtures it is not as obvious as on some other cars. I have seen 33s going down the road blowing clouds of black smoke with their drivers blissfully unaware. It usually shows up as a flat spot on accelleration and a slowing of the idle when sitting at the lights etc. The weight should be 10gms and anything above 11 to 11.5 is bin material. On the above carbs the idle mixture adjusting screws are on the outside of the carb at the bottom, recessed in a tube and one per each throat. In for lean, out for rich or clockwise for lean, anti clockwise for rich. Hope this helps.
Eddie w

[87Sprint]

Quote:

Originally Posted by Eddie W Hi, because of the twin carb setup it is not unusual for the plugs to show rich in stop/ start running, however if you have Dellortos then it would be advisable to check the float weights as they become heavier over the years leading to a gradual enrichment. This is inclined to creep up almost unnoticed and as the boxer seems to be very tolerant of over rich mixtures it is not as obvious as on some other cars. I have seen 33s going down the road blowing clouds of black smoke with their drivers blissfully unaware. It usually shows up as a flat spot on accelleration and a slowing of the idle when sitting at the lights etc. The weight should be 10gms and anything above 11 to 11.5 is bin material. On the above carbs the idle mixture adjusting screws are on the outside of the carb at the bottom, recessed in a tube and one per each throat. In for lean, out for rich or clockwise for lean, anti clockwise for rich. Hope this helps. Eddie w

[tubut]

I'm not sure if this applies to boxer's as well: Several Alfa mechanics have told me that their prefered way of a tune-up is to take customer's car, warm the engine up, and then drive it in the upper RPM range for about 20 minutes so that the carbon build up disappears. While this does not take care of any possible problems with the carbs, it is a cheap and fun way to keep your car in shape (unless you encounter cops).

One of the mechanics also recommended to install hotter spark plugs (1 or 2 steps hotter) for daily driving in commuter traffic (i.e. for cruising instead of driving).

Good luck,

Ruedi

[87Sprint]

Quote:

Originally Posted by tubut I'm not sure if this applies to boxer's as well: Several Alfa mechanics have told me that their prefered way of a tune-up is to take customer's car, warm the engine up, and then drive it in the upper RPM range for about 20 minutes so that the carbon build up disappears. While this does not take care of any possible problems with the carbs, it is a cheap and fun way to keep your car in shape (unless you encounter cops). One of the mechanics also recommended to install hotter spark plugs (1 or 2 steps hotter) for daily driving in commuter traffic (i.e. for cruising instead of driving). Good luck, Ruedi