I use 15% Nitro fuel for all my 2 stroke engines and recently I bought a 4 stroke engine. Question is can I use my 2 stroke fuel for my 4 stroke engine ? If it is not advisable, can I modify my 2 stroke fuel e.g. adding certain % of lubricant. Thanks........

I use 15% all synthetic oil in 2 and 4 strokes engines with no problem. I have just recently started using Wildcat #109. This is a 2-4 stroke fuel with 15% nitro and 18% oil. Has a very nice smell also.

Kevin

What exactly are you using now?

Fuelman

Hi Fuelman........I am using SIG 15% Nitro, 20% lub (1/2 castor, 1/2 synthetic).

Rajul,
Using that fuel will not hurt anything in the 4-strokes. You may over time experience an excessive amount of burnt castor buildup on the valves and some gumming of the ring land with a high castor content. The bottom line is that the fuel you're using does have enough lubrication and none needs to be added for most any 4-stroke on the market today.

If you have the availability in your area, an all synthetic fuel or a fuel with the majority (80% or 90%) synthetic will best suit 4-strokes as long as it has enough total oil in it to satisfy the engine manufacturers oil recomendations of your 4-stroke.
A little bit of castor in a 4-stroke fuel will help with keeping rust away without gumming anything up.

Fuelman