hsp-sandiego

iTrader: (7)

have a O.S. 21 XM outboard on the way and I have both 30% and some 50% aquacraft nitro. O.S. states up to 30% nitro for this motor and was looking to order some Torco nitro because you can buy a gallon for $40 shipped; minimum nitro for their marine is 50%. Anyway, any reason O.S. would limit this motor to 30% as most smaller nitro boat motors run on high nitromethane content such as 50, 60%. Anyone run this motor on 50%?

appreciate it.
thanks, Harry.

Ron Olson

O.S. is playing it safe by recommending only 30% nitro. .21's love the stuff so going higher won't bother it. 50% will be fine, just richen the carb some.
Me, I'm a little crazy as I've been running 65% Wildcat for years in everything from .12's on up to .45's.

hsp-sandiego

iTrader: (7)

thank you for confirming. and how about the O.S. #8 plug? I see it is spec'ed as a medium plug. running 50% in the "cold" to very cold range. will any short plug in the cold range work well? maybe the A5/#10 ?

thanks again.
diggin' the nitro stuff; sick of charging batteries. LOL.

Ron Olson

I like cold plugs myself for high nitro fuel. My old standby plug was the McCoy MC-9 as it seemed to work in everything. O'Donnell plugs are supoosed to be very good. I never tried any O.S. plugs.

hsp-sandiego

iTrader: (7)

cool.. thanks again. the O.S. plug is a shorty as with all O.S. engines (i believe) so will try their #10 with the 50%. new motor setup and going to run here the next two days.

thanks again.