When I first saw this thread I thought someone had figured a way to get horsepower from menthol cigarettes.

**** you must be really really smart...my favorite comment....boy do I feel stupid.

Thanks for your insight. I can tell your an expert. I digress.

funny, I coulda swore that mercury recommended 92 octane on the 300 pro max and the 300x promax

well I should state that I know for FACT that the on the 300x 92 octane or better is called for...I'd have to look the 300 pro max up...but your the expert.

I might be wrong on this, but I think 300 pro max compression is around 120-130 not to be more then +/- 15 lbs . Page 1-21 of the service manual. Can you show me otherwise?

you're an idiot.

3.0Ls don't need oil injection blockoff kits, because even the old ones dont have POS plastic drive gears.

bridgeports are 240ish HP. 260s 280s and 300 drags are not bridge port engines. they arent even the same displacement :rolleyes:

a 300 promax requires 91 octane minimum.

and you cant spell worth a ****. :grinser010:

He forgot more then you ever knew about outboards. Don't argue with him.

Go take the potatoes out of your bilge and get your bridgeport 280 running on some 77 octane and go for a boat ride since your not currently under seige by a hurricane.

To the original poster, I personally wouldn't chance any guess you didn't feel comfortable with. I always run any gas that I think may be questionable through my truck and re-fill my boat with new fresh fuel.

i'm sorrry, i didn't know this was a spelling contest. my bad. 120-130 #'s of compression is standard for any 150-300 hp, stock production Mercury . If they don't require the higher octain, they why would this gentleman need to run it in his. All I was trying to get across was the fact that he can't hurt his motors by running the lower grade fuel........

Interesting way of getting your point across...So if mercury recommends high octane fuel what in your vast experience of forgetting more about outboards then the rest of us leads you to believe it's not necessary?

I'll check our local sherwin williams paint store. When I was looking a few weeks ago I checked the building supply center,lumber yard and small town hardware store in the hick town I live close to but all three said they no longer sold it,they used to have it in 1 and 5 gal cans but didn't know why it was no longer available/stocked. Until 2 weeks ago I could buy torco 110 for 4.89 a gal,now it finally jumed up to over 6$ a gal. I throw 10 gallons in with 50-60 gals 93 octane when my boat hasn't been run for a few weeks and I know I'm going to be holding it in boost to help ensure my octane hasn't degraded from the poor characteristics of ethanol gas sitting. This spring was the first year my local station no longer sold 93 octane without ethanol,Smitty

do the math........and im out................

so I guess that mercury recommends 91 octane or higher in their owners manual just because they feel like it then? :rolleyes:

What math is to be done? You do realize that compression alone is not the only factor to determine which octane fuel a 2 stroke outboard engine requires right?

Typical I don't have anything to back up my opinion so I will just call you stupid internet answer....

Congratulations.