Too much wet soot spraying out exhaust tip on start up....

Rentalman

Active member
Good afternoon all. I may need a little advise on carb set up. Everytime I start the Scout up I have to put a piece of cardboard in front of my exhaust tip to catch the wet-soot that sprays out of it.

The engine is a 345 that has been rebuilt, balanced & blue printed with ported & polished heads. It has a Isky split durration cam, headers, Pertronix ignition and a Holley 2300 7448 2-barrel carb. The carb is in stock form from the factory with #61 jets & 8.5 power valve with the idle mixture screws set at 1 1/2 turns out. If I turn the screws in or out from here the vaccum drops to 14. Since the rebuild I have logged 150 miles on it driving no faster than 40 mph slowly breaking everything in.

After the engine is warmed up, my timing is at 10 deg BTDC, 700 RPM's in drive (TF 727 Tranni), vaccum is at 14.5 - 15. Should I change out the power valve to a 6.5 or 7.5? Is the 8.5 power valve taking on more fuel than needed? Sequence of starting Scout. Push gas pedal down 1/2 to 3/4 way with manual choke closed. It starts and I feather my foot on the gas pedal for a second as I push the choke in half way. Then it idles fine. After a few minutes I open the choke more. When I take the Scout out and drive for about 15 miles, the engine runs great. At stop lights with foot on brake pedal it idles great, no stalling.

Since this is a rebuilt engine do my rings need to seat more? Would you think engine oil is part of my black soot? The engine does not blow smoke out of the exhaust when I'm driving it. I have included pics of the spark plugs for your viewing. I did notice #7 & #8 spark plugs had a better burn. Also one side of plugs are darker than the other. Plugs are Champion RJ12YC gapped aroud .37-.38.

As always I appreciate all advice & suggestions. Have a Great Day!
 

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what elevation are you at ? and what is your vacuum with a warm engine in P

my scout has done the same thing for 48 years with the watery/soot i think that is just physics of hot exhaust cooling and condeaditing moisture in the air. modern cars do it also, but they have a little hole in the muffler so it drains and dosent collect and get blow out when started.
 
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