Fuel mix mystery.. at least to me.

[meyerboy]

I have always just done what OMC tells me to, but I am getting older now, and I want to know why.

I have a JW12 (1956) that requires 16/1 fuel mix, a JW16 (1960) that requires a 24/1 mix, and two JW22's (1967) that calls for 50/1.

I THOUGHT that all of the 3hp motors above were the same powerhead.

Can the wisdom of the OMC advise team help me?

 

[JB]

Re: Fuel mix mystery.. at least to me.

During the span of time between the JW-12 and the JW-22 several things changed. Superior lubricants came along, OMC changed some specs and some materials.

I would stick with what OMC said back then and BRP is recently reinforcing.

 

[Daviet]

Re: Fuel mix mystery.. at least to me.

Usually the 16/24:1 engines had babbit type bearings and the 50:1 had needle bearings on the crank and rods.

 

[Vic.S]

Re: Fuel mix mystery.. at least to me.

Usually the 16/24:1 engines had babbit type bearings and the 50:1 had needle bearings on the crank and rods.

And with no needle rollers in any of the three mentioned I dont think I would risk 50:1. 24:1 maybe but perhaps but no less oil than that.

Not only a question of lubrication but with no crankshaft oil seals they rely on the oil film in the bearing to seal the crankcase.

 

[Daviet]

Re: Fuel mix mystery.. at least to me.

Vic.S, doesn't the 1967 use needle bearings?

 

[Vic.S]

Re: Fuel mix mystery.. at least to me.

Vic.S, doesn't the 1967 use needle bearings?

It does not appear to See here

.

 

[Daviet]

Re: Fuel mix mystery.. at least to me.

I stand corrected. I keep forgetting about the small engines using babbit bearings longer than the larger ones. Sorry for any confusion.