Spark Plugs
 

I run a 540 Merlin with a 871 Super Charger, with two 850 Demon Carbs., 10lbs of boost and am experiencing a huge amount of black soot on the transom. I was thinking of switching to a Champion Projected Fine Wire Spark Plug in hopes to reduce and/or eliminate the soot problem. Looking for any feed back from folks who may have had similar problem and/or running the same setup.

Problem is not your spark plugs but jetting in your carbs. In a blown motor the jetting is important not to get too lean, Get rich & transom gets black & you get to see black soot on water when starting motor. Jetting is a tricky subject. If you do a search you will find many threads on subject. I have procharged 540 & I spent 4 weekends & lost count of times tearing carbs down to rejet to get jetting right.

To start getting jetting right need to first find out what jets you have in carbs & what power valves you have. Are your carbs boost refrenced? Need to buy a bunch of spare spark plugs.

Earlier threads go into all the detail on how to check. Just remember "Black transom is better then Melted Pistons"

Ihave 3.5 power valves,I have 87 jets on the primary,94 jets on the secondary.My pyrometer gauge is 1250 degrees on the primary wot is 1425 degrees. I thought a change in plugs might help.Ihave been using accels 141-plugs.