Thread:

What is correct oil /gas ratio?

Why is their a difference of opinion on 2 cycle mix ratio? I'm new to outboards,454 for many years,allways on Havasu.Bought a 1997 Stoker with a 2.5 efi Merc.Thru several guys recomendation here i was able to have the engine rebuilt completely.The guy did a awesome job. For break-in the mix is at 30 to 1 and they are saying after break-in 40 to 1 . I found a mix bottle in the boat and can see the original owner was mixing 32 to 1 . Would appreciate opinion on this. For sure the guy who rebuilt the engine knows his business and for many years.

Those ratios sound perfect for that motor (I'm guessing a 2.5 200hp efi?). I ran my 2.5 280 at 32:1 when I would be running it hard, and 40:1 when I would be taking it easy (not often). The lower hp and rpm of your 2.5 200 will be fine on 40:1 for all types of running.

Originally Posted by Rayzor

Those ratios sound perfect for that motor (I'm guessing a 2.5 200hp efi?). I ran my 2.5 280 at 32:1 when I would be running it hard, and 40:1 when I would be taking it easy (not often). The lower hp and rpm of your 2.5 200 will be fine on 40:1 for all types of running.

Thanks Rayzor.

A 2.5 260 you need to run 32:1 not 40:1!

I agree with Dale the only thing I might add is that I would spend the extra and use 100% Synthetic after your break-in period.

Originally Posted by badbait

I agree with Dale the only thing I might add is that I would spend the extra and use 100% Synthetic after your break-in period.

Good call Bill. I forgot to specify in my post that I always ran Red Line Oil Racing 2 Stroke Oil (the red stuff) at those pre-mix ratios. Believe it or not, Chris Fairchild has me running Yamalube R at 20:1 in my SST120 motor! It's the oil he prefers, and under race conditions/rpm, he recommends 20:1. In my Optimax motors, I run the Mercury recommended oil, which I believe is some really odd Mercury oil for my new 2.5/200XS/ROS motors. I'll know when I get the motors here in April/May. How's your hot rod Cougar doing?

How's your hot rod Cougar doing?[/QUOTE]

I got busy working with Scott and Steve testing the War Canoe before the Parker. I did go out one more time and ran a 32 Hoss on my Cougar to 113 mph. It was warm and the water was very flat so there may be one or two more mph left in it. Not bad for a stock 280 on a 21 Cougar, I'm actually quite surprised that I'm running those numbers.

Thanks,

Originally Posted by badbait

How's your hot rod Cougar doing?

I got busy working with Scott and Steve testing the War Canoe before the Parker. I did go out one more time and ran a 32 Hoss on my Cougar to 113 mph. It was warm and the water was very flat so there may be one or two more mph left in it. Not bad for a stock 280 on a 21 Cougar, I'm actually quite surprised that I'm running those numbers.[/QUOTE]

That's awesome Bill! You've got quite an impressive rig. You need to weigh it some day, I bet it only weighs around 1,400 fully rigged out with no fuel.