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Folks, 1957 Series 1 (2ltr) running very rich (as in smoke from the tailpipe and odor). I put a new carb on it with no change. I cleaned the oil bath air filter and reassembled. I adjusted the timing to 6 before TDC. The air hose (cleaner to carb) has oily black coating inside. Changed all four plugs last night.
What else can I check/do? THANKS for any input...I am learning mechanicals as I work on this truck so this is all fairly new to me.
Sounds like the air/oil bath unit needs cleaning - if it's clogged (or overfilled) it will restrict air, causing excessive vacuum in the carb that will then cause the carb to draw in more fuel. Sounds like it may be introducing oil onto the air mixture as well - adding to the smoking effect.
You said you cleaned it. How well? Did you get the filter element out? Brake cleaner? Did you only fill the air filter bowl with oil to the line?
Other suspects - piston ring wear, allowing oil from the sump to be introduced into the burn. Have you compression tested the engine?
What did the old plugs look like? Can you post a picture of the business ends here?
The air cleaner element does not come out (it is crimped into the upper cannister). I sprayed brake cleaner into the mesh, let it sit for a few minutes and then sprayed it again. I also mopped-out the bottom oil bowl and refilled it to the line. I have not done a compression test but I will (once I learn how to use the gauge). I have attached a pic of the plug, and all four looked the same: very black and plug #4 was also a bit wet. Thanks for the assistance!
Attachment 12723
Plugs seem to confirm the rich condition. Brake cleaner ought to have cleared out that filter. Sounds like the compression test is the next logical checkpoint.
Super...I will do that tonight. Looks like you are about 45 minutes from me. Maybe our paths will cross sometime.....and thanks.
Yep - we're close. Looked at some of your older posts. Looks like you have a few Series trucks in your fleet!
Also - be sure that throttle is open (to the floor) when conducting the compression test.
Will do!
Compression came back all around 120..so that seems good. Next I will double check the mixture and idle screws on the new carb and most likely fit a different, more breathable air filter to see if that makes a difference. If that doesn't fix it, I will try to measure the fuel line pressure in case it is too high from the pump. Any other thoughts...and thanks!
120 is good and rules out oil bypassing the rings. I like your thinking on going back to the carb and working on the fuel/air mixture.