OVER octaning a 2 cycle engine

[Jay Smith]

A 2 cycle engine has but an approx. 1.500" window to contain the total push that combustion creates. If the burn is not complete some of the push is lost because of its escape out the exhaust port. Equals loss of power. High octane fuels burn slower than pump gas and if the compression of the engine doesn't warrant the use of higher octane to prevent detonation the loss of power is apparent . The higher the octane above what is needed to prevent detonation the MORE power will escape as well as dollars from your pocket book....

Even at 225 lbs cranking compression at sea level I blend my race guys engines fuels and don't run "straight" 112-110...We have found through testing that one that has a handle on the weather conditions ( I use a Kestrell 4000 weather station to set fuel air raio for that particular day ) and fuel octane has an advantage from those that "guess"..

About oils I break-in on petrolium only and then on steel sleeved engines ( what you have ) use ONLY blends no 100% syn oils on steel, I've learned that lesson the hard way ..

Good luck,.

Jay

[larby]

That's a good one to know. Seems obvious now but I'd never thought of it before!

Thanks Jay!

[odyssey aka Blue streak]

Again good to know. Had thought about high octane fuels and the advantages they bring but never the disadvantages that it also brings.

Very good point raised there

[larby]

The most common mistake I see is people adding too much oil, 25:1 or so, thinking it's good for the engine to have a bit more. Not realising that they're actually leaning out the fuel both by diluting it with oil and making it more viscous therefore meaning less of it travels through the jets.