2 cycle fuel mix

Apr 23, 2017
15
O'Day Day Sailer 3 Lake Nockamixon, Pa.
Does someone have an idea what the mix would be for an older Mercury 20 hp outboard. I think it is about 1980? My son is about to use it and has forgotten the ratio he used.
 
Feb 8, 2014
1,300
Columbia 36 Muskegon
Just about everything uses 50:1. Some chain saws are 25:1 though. I once had an Evinrude 9.9 that was labeled 100:1 but the dealer advised they had a lot of them seize up and I should use 50:1. Ran fine on it, a little smokey, but they all are.
 
  • Like
Likes: sail sfbay
Apr 23, 2017
15
O'Day Day Sailer 3 Lake Nockamixon, Pa.
These answers confirm what I thought, but wasn't sure of. Thank you to everyone for the answer!
 

RussC

.
Sep 11, 2015
1,578
Merit 22- Oregon lakes
And use a high quality oil. it will smoke/pollute less as well as better protecting the engine.
I owned an outdoor power equipment business for 31 years. when customers would ask me if I liked brand x oil from the box store. I always replied "I love it. it's a guarantee you'll remain a customer in my repair shop". ;)
 
Last edited:
  • Like
Likes: Allan12210
May 24, 2004
7,129
CC 30 South Florida
A 20 HP 2 stroke engine should weigh more or less around 80 lbs. Check the rating on the motor mount if used in a small sailboat.
 

Tedd

.
Jul 25, 2013
745
TES 246 Versus near Vancouver, BC
These days, 50:1 is typical. But in those days 40:1 was the norm. Maybe oil is better and 50:1 with modern oil would be fine, but if it were my motor I'd use 40:1, if I couldn't find an authoritative source that said otherwise.
 

Tedd

.
Jul 25, 2013
745
TES 246 Versus near Vancouver, BC
All my two stroke motors in the 70s specified 40:1. But, of course, that's not really the point. The point is that, in the absence of an authoritative reference for the specific engine in question, 40:1 is the safer choice.
 
Last edited: