A few months ago i had a engine rebuild done. I got the shop to rebuild the motor and to cut costs down i put it in. Now my problem is that it keeps fouling up the spark plugs. He has gone to the tailpipe and wiped his finger inside bringing it out all black and says it is "Over fueling" I know it is not as i have a 650cfm Holy carb on it that was just rebuilt by a reputable company here in town they put it on and set it up for me. WHat else can cause this Black soot in the tailpipe? I want this guy to Honor his warrenty but i have no idea what to tell him when he comes up with this Over fueling argument. What i should have done is did my homework and found out before hand what a croock this guy is. But since i have not i need some other alternitive without spending another 11 hundred bucks.

 

Welcome to thirdgen.org.

Black soot would indicate it's running a rich.

Not sure I'd be looking at the engine builder just yet, have your carb guy monitor the air/fuel ratio and see how it's doing...not just in park/nuetral, but also under driving conditions.



Could be in need of a carb tune, distributor ajustment, etc.

Is the engine rebuilt stock or for performance? Both would alter the way the tune would be done.

Only thing I could see the engine builder not doing correctly that could cause extra fuel/poor combustion, would be incorrect cam install, or misadjusted valves.

 

I agree with Mike,

Sounds like you are running rich. I would talk to the people who worked on your carb before the engine builder.

-peace

 

Kushal,

Welcome aboard!

You're about to find out just how "reputable" your carb rebuilder really is. The soot is NOT from the engine rebuild, unless there is absolutely no oil left in the sump. Even that usually makes an oily black residue, not dry soot.

You are most certainly running rich under some conditions, and can't blame the engine rebuilder for that. As previously suggested, contact the carb rebuilder and ask to have the carb adjusted based on A/F ratios under load.

 

Even if the carb is assembled properly,it may be jetted wrong for your engine. Lots of carbs are just taken out of the box and installed without any thought to tuning [getting it jetted right etc.] If it's a universal model it can't be be right for all engines.