this is not automotive, but has anyone had any problem with spark plug fouling with synthetic aftermarket lube, pennzoil , obctw3, etc, certified with a big outboard,, 200hp? thanks, rlw

RLW,

Correctly recomended lube alone less likely to foul spark plugs, Synthetic or otherwise.

Check fuel? Could be "emptyish" tank when the dirt at bottom gets picked up?

Outboard is like 2 stroke motorcyles. The lube is mixed with the fuel and such lubes have special dispersent package to enable speedy mixture of the lubricant into the fuel. If the lube (synthetic or otherwise)does not have this package, it will settle to the bottom and slowly form a mixture with the fuel. Meanwhile, if the engine is started, then the bottom layer (the lube) will get drawn in. In this case it will surely foul the spark plug as fuel to lube ratio is way off. The flash/fire/vapour point of lube is 220 plus C, while that of the fuel will be barely 40 C. This mismatch will result in poor burning and high deposits are anticipated.

Does it run on Kerosene? If so more likely to happen as kerosene is more dirtier than other fuels.

Hussam Adeni