100:1 mixture?

[roach502]

my 1985 30hp evinrude has a 100:1 sticker on the side and was just thinking this seems a bit on the lean side,i am useing a full synthetic oil but would like to here some input on this topic. i have just completly rebuilt motor,bore,pistons,con&crank bearings,and a good polish with a set of boysens to boot! hope she runs fine.thanks guys

 

[Joe Reeves]

Re: 100:1 mixture?

The 100/1 was a OMC goof that resulted in many blown powerheads. Avoid this mixture!

Use the 50/1 mixture in that engine.

 

[dazk14]

Re: 100:1 mixture?

my 1985 30hp evinrude has a 100:1 sticker on the side and was just thinking this seems a bit on the lean side,i am useing a full synthetic oil but would like to here some input on this topic. i have just completly rebuilt motor,bore,pistons,con&crank bearings,and a good polish with a set of boysens to boot! hope she runs fine.thanks guys

Don't forget 25:1 for break in and wait until broken in before running full synthetic. Think xd-25 or xd-50 or any other quality oil. The concern with full synthetic is the cylinder walls will glaze before breaking in.

Expect to tweek the idle mixture with the boyesen's - usually richer. I wouldn't want you to have a heart-attack on start up if it runs a bit rough!

 

[1946Zephyr]

Re: 100:1 mixture?

Yep, I second what Joe Reeves said. I had a 1986 Evinrude 25 that benefited from a rebuilt powerhead, because of the 100:1 mix. Got me a nice motor with a rebuilt powerhead for free.

 

[jasper60103]

Re: 100:1 mixture?

I have two 30 hp motors from that era. Good runners. Don't forget to remove the sticker.