no it will not harm your motor, however you should be down on power, not up. the higher the octane, the lower the BTU content, however the harder it is to ignite. hence the reason for high compression motors to use it to control detonation. if you have a boost in performance, you were suffering from detonation prior. as asked by pnwboat, where is your ignition timing?
Either the timing needs to be set correctly or you have high carbon build up causing pre-ignition when using regular octane gas. A borescope will be helpful in finding out if it is carbon build up. It doesn't have to be the expensive type. I bought a mini-borescope from the bidding site for less than $20. It is tiny and not as bright but it works.
More like a placebo effect, there's nothing about 93 that will boost performance.
It is possible that you were running E-10 and the 93 was E-0, this could result in a slight increase in power, but it's not normally noticable. The difference has nothing to do with the octane rating though.
I worked at a marina that sold the super premium for the local hot boat crowd.
My boss got his fuel at cost and used it in his twin Johnson 300's and said it contributed to his burning up an engine??
The burn lasts longer and is supposed to raise exhaust temps???
These were made for regular gas and I'm pretty sure the engineers know way better than I do.
Plus the premium leaded is $1.00 more a gallon here.
Thanks Guys Timing is perfect. mabey a little carbon in the bores. going to wait till the end of the season to de-carb. I don't want to risk my season. She's running great on a Bayliner 17" capri 36mph with a 17p prop at 5000rpm
