Xanax1961
Active Member
Hey Guys, What's your favorite choice of two-stroke engine oils as far as engine protection? TIA (99 225 Promax, oil injection system removed)
Best 2-stroke oil
- Thread starter Xanax1961
- Start date
Haha! Can o' worms! This is gonna be both a long post here and a long thread... and likely will have a great variety of excellent choices presented. When in doubt can't go wrong with the Mercury oil type specified for the type of Merc motor. The motors with air compressors use the top end stuff. Quickcleen is a good Mercury product to run in the fuel as well.
Now this is likely to be thought of as pretty damn weird, but here goes. Am definitely expecting to take some flack for this but know I am standing by my post no matter what... because I have decades of experience with this product in both water and air cooled engines, including high performance pro level chain saws as well as air and water cooled snowmobile motors. Those air cooled 2 stroke motors run way hotter and more RPM than any outboard under normal operating conditions. High piston speed along with high brake mean effective pressure creates a recipe for short engine life without excellent lubrication of metal surfaces.
Back in the 80's a new 2 stroke ash less oil was engineered in Texas. The carrier oil is food grade mineral oil with a special additive. It was used in the nitro/alcohol burning 2 stroke drag motors with great success during that time, even sponsoring some events. It uses what is called a phosphamid molecule, that additive does a surface treatment on the metal surfaces inside the motor, actually chemically reacts and converts the metal surfaces with the result of lower piston temps, lower friction, nearly or no smoke when warmed up, and reflects more heat back into the combustion chamber. The result is less wear of moving parts than more conventional oil formulas. The conversion process takes place for the first 45 minutes running the motor at fast idle. That oil also lifts carbon off metal surfaces during that process. My room mate and I did it to his 30+ year old 4 cyl Johnson 85 two years ago. At the start of the experiment we pulled some spark plugs and shined a light onto the pistons to see the carbon. It was built up unevenly a good sixteenth of an inch thick. 45 minutes later after shutoff we pulled the plugs and took another look. During the conversion a cylinder would occasionally miss from carbon getting in the spark plug gap. It would clear itself. We pulled the plugs again and took a look after shutdown... we could see the metal piston top through a very very thin layer of remaining carbon! In my Dad's old Bayliner/Force cross flow 85 I got two more MPH top speed after changing over to this oil. The tops of those pistons are bright and shiny metal! I also use Yamaha Ring Free with that oil. In tests that oil protected down to a 400/1 ratio. I was working for a boat dealership at the time and had some long phone conversations with the marketing director about the product, so I feel like I did due diligence by reading the results of the tests as well as asking him lots of questions. In snowmobiles this oil greatly reduced emissions to more like what a 4 stroker would do.
It's called Blue Marble, and I get mine in a case of four gallon jugs for around 42 bucks a gallon on eBay or Amazon, similar in price to the Optimax specified Merc synthetic blend. Yamaha's Ring Free is expensive, but only require a small amount, I use 1/2 ounce with every 5 gallon can of fuel I premix. I mix in the cans and siphon that mixture into the boat tank.
Hope this info helps. All the best to ya.
Now this is likely to be thought of as pretty damn weird, but here goes. Am definitely expecting to take some flack for this but know I am standing by my post no matter what... because I have decades of experience with this product in both water and air cooled engines, including high performance pro level chain saws as well as air and water cooled snowmobile motors. Those air cooled 2 stroke motors run way hotter and more RPM than any outboard under normal operating conditions. High piston speed along with high brake mean effective pressure creates a recipe for short engine life without excellent lubrication of metal surfaces.
Back in the 80's a new 2 stroke ash less oil was engineered in Texas. The carrier oil is food grade mineral oil with a special additive. It was used in the nitro/alcohol burning 2 stroke drag motors with great success during that time, even sponsoring some events. It uses what is called a phosphamid molecule, that additive does a surface treatment on the metal surfaces inside the motor, actually chemically reacts and converts the metal surfaces with the result of lower piston temps, lower friction, nearly or no smoke when warmed up, and reflects more heat back into the combustion chamber. The result is less wear of moving parts than more conventional oil formulas. The conversion process takes place for the first 45 minutes running the motor at fast idle. That oil also lifts carbon off metal surfaces during that process. My room mate and I did it to his 30+ year old 4 cyl Johnson 85 two years ago. At the start of the experiment we pulled some spark plugs and shined a light onto the pistons to see the carbon. It was built up unevenly a good sixteenth of an inch thick. 45 minutes later after shutoff we pulled the plugs and took another look. During the conversion a cylinder would occasionally miss from carbon getting in the spark plug gap. It would clear itself. We pulled the plugs again and took a look after shutdown... we could see the metal piston top through a very very thin layer of remaining carbon! In my Dad's old Bayliner/Force cross flow 85 I got two more MPH top speed after changing over to this oil. The tops of those pistons are bright and shiny metal! I also use Yamaha Ring Free with that oil. In tests that oil protected down to a 400/1 ratio. I was working for a boat dealership at the time and had some long phone conversations with the marketing director about the product, so I feel like I did due diligence by reading the results of the tests as well as asking him lots of questions. In snowmobiles this oil greatly reduced emissions to more like what a 4 stroker would do.
It's called Blue Marble, and I get mine in a case of four gallon jugs for around 42 bucks a gallon on eBay or Amazon, similar in price to the Optimax specified Merc synthetic blend. Yamaha's Ring Free is expensive, but only require a small amount, I use 1/2 ounce with every 5 gallon can of fuel I premix. I mix in the cans and siphon that mixture into the boat tank.
Hope this info helps. All the best to ya.
Last edited:
Xanax1961
Active Member
Very good info and read buddy, much appreciated. I saw it used in some OBDA videos on youtube.
SLOmofo
Well-Known Member
Blueally XB21
Active Member
I use Alisyn and purchase here, https://www.aerospacelubricants.com/
If you are a member of scream and fly you can get free shipping as well. Used it for many years with no issues. It is a full synthetic oil as well.
If you are a member of scream and fly you can get free shipping as well. Used it for many years with no issues. It is a full synthetic oil as well.