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| | | Joined: Nov 2003 Posts: 236 Shop Shark | | Shop Shark Joined: Nov 2003 Posts: 236 | Hey guy's I have a 51, 235 in my 52 1/2 ton. It runs great,(other than the lifter than bleeds down overnight). Question is, why is my exhaust so sootie. It is black and powdery. I can almost sweep it up. It doesn't matter what I do to the mixture and timing. Any ideas? The truck doesn't smoke but does leave a black deposit on the floor.
Glenn, | | | | | Joined: Jul 2004 Posts: 5,708 'Bolter | | 'Bolter Joined: Jul 2004 Posts: 5,708 | Glenn,
The soot (dry) is the product of a rich fuel/air mixture. This means too much fuel which is probably a carburetion problem.
I would do the basic things first which would be to make sure your choke is coming completely open, your power valve is open to manifold vacuum and the float adjustment is dead on. Check your air cleaner too, it must not restrict any flow.
Stuart
| | | | | Joined: Nov 2003 Posts: 236 Shop Shark | | Shop Shark Joined: Nov 2003 Posts: 236 | Thx Stuart,
I'll check the mixture. The chock is manual and I know it is full open since I've checked it many times. You got me on the power valve though. What and where is it? I haven't checked the float since I bought the carb new. I'll look up the specs on that. Thx.
Glenn, | | | | | Joined: Jul 2004 Posts: 5,708 'Bolter | | 'Bolter Joined: Jul 2004 Posts: 5,708 | Glenn,
The power valve is a doo-dad inside the carburetor that gives it a little extra fuel when vacuum is low. This would be when you are climbing a hill or have your foot in it, so to speak.
The base gasket has holes that be aligned under a little passage in the base of the carburetor...sometimes the phenolic spacer has a small notch too. The passage inside the carburetor must be open to the inside of the manifold. I think checking the float level would be good insurance too.
Those are a few of the things that could cause a rich mixture. Maybe someone will be along with more things to check out. Good luck.
Stuart | | | | | Joined: Nov 2003 Posts: 236 Shop Shark | | Shop Shark Joined: Nov 2003 Posts: 236 | Thx Stuart,
Now I know what your talking about. I'll pull the carb to make sure that I didn't put the insulator on backwards. I do know that the notches are at the top.
GEC, | | | | | Joined: Oct 2001 Posts: 3,458 Extreme Gabster | | Extreme Gabster Joined: Oct 2001 Posts: 3,458 | Once you soot up an exhaust, it takes a while for it to clear out. The best way to check your mixture (shy of a gas analyzer) is to read the plugs.
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