[DANNY II]

I just bought a new '08 Yamaha 25hp and the dealer was an older gentelman who told me to mix my oil 50:1 vs. the 100:1 ratio listed on all the motor information. Granted I know during the break in period you are supose to mix it rich for the first two tanks of fuel but he said to mix it 25:1 during the break in period. Correct me if I am wrong but mixing it that rich will fowl out the plugs, right? Am I correct in thinking I should mix it 50:1 during the break in period and then back it off to 100:1 after that?

[rodbolt]

actually I think breakin on that engine is 25 to 1.
after that listen to the old man, its already obvious your not gonna read your owners manual, as expected, so the 50/1 is simply trying to save you from yourself.
trust me, after the breakin run 50/1 unless your gonna maintain it as PER THE MANUALS yearly OR calander maint schedule and run it at least once per week under load for 30 minutes or more.
its all in the manuals, no one ever actually reads them.

[bowhuntrrl]

MORE OIL=LONGER ENGINE LIFE !!!!! 100:1 is way too lean unless you will only be trolling 100% of the time.

[rodbolt]

more oil DOES NOT mean more life. it means some insurance against fuel system or cooling system degradation as well as corrosion(rust) protection on all the shiney parts inside the engine.
if the fuel system and cooling system is kept in perfect top notch shape, and its fogged if unused over 30 days(as per OWNERS manual) it can run wot for hundreds of hours on 100/1. only difference notiable to the customer is the cost of twice the oil.
unless something goes degraded, then as its already on the edge it will simply munch a piston or toss a rod.
my 175 E-TEC did it, ran it 15 hours over 17 months, was my fault but BRP covered it.

[bowhuntrrl]

Well, only time will tell if the 100:1 mix will let an engine live like the old 1950's and 60's Johnsons and Evinrudes that I have !!! Running at 25:1 and still running 48 years later, and running like new !! Sure the new engines are "supposed" to be designed to run on 100:1, but I'll bet money right now that they won't still be running in 50 years !!! In fact I bet they won't run for 15 years, just not enough lubrication, even with the modern lubricants.

[Snowdrggn]

I run my 25hp Yamaha at 50:1, not the 100:1 specified. I fog it when I put it to bed for the winter. I change the plugs AFTER I start it for the first time for the season (just cuz I think I should), then run it hard all season on an inflatable. Other than regular l/u oil changes and a water pump every second season, it gets very little maintainance. It has never even sputtered, or quit without using the kill button. It probably has over 2000 hours on it since I bought it new in 1988. Oh yeah, I also check the operating temp once in a while to make sure the t-stat is functioning properly.

50:1 seems to work in my books.......

Cheers,
Snow.

[bchoate]

We can all thank the "Higher than God almighty" EPA for the lower oil mixture regulations. Rodbolt seems to be right on the money with most replys.
I would run 50:1 mixture also, but that can cause more problems with combustion deposits. I would also recommend the constant usage of Ring-Free or simular additives as recommended in your owners manual ("YES" read it.)