OMC 100:1 mix?

Question

Some week ago there was a topic about older OMC engine mix.

I replied that only Yamahas mix 100:1.

Then there was a reply that said:

"Frank is wrong, there are some OMC outboards that run 100:1.

I have a Johnson 15 hp which is one such engine."

I was wrong on the answer but not realy.

There were 9,9 hp and 15 hp johnsons sold in `81 until `85 with 100:1 mix decals, but..... In `85 OMC came back on this and mailed the dealers to remove these 100:1 stickers and to replace the sticker with the 50:1 mix.

They found problems with the engines running the100:1 oil mix.

If you still run it 100:1 it is your choice but you are not up date!! No offend though, just to straighten this out

I wanted to give the person asking this question about the mix on his johnson a good and non questionable answer.

Frank

Answer 1

This is true.  I have a 1984 6hp evinrude that the original manual said to mix at 100 to 1 ratio.  Later a change bulletin was sent to me to disregard manual and use a 50 to 1 mixture.  I never had the decal on the engine changed. Fortunately I didn't trust using the 100 to1 mix from the start and always mixed  50 to 1 except for the first couple of tanks which I used 40 to 1.

If anyone out there has purchased one of these old engines and it's labeled with 100 to 1 disregard it and use 50 to1 to be safe.

Answer 2

I remember commenting that I didn't know of any 100:1 OMC - but now, hearing the whole story, I do recall that happening.

If you'll pardon a little off-topic chatter -  I think I have an SB around here somewhere, putting some of the older 24:1 motors on 50:1......

There are some oil manufacturers recommending 100:1 with their oils even in 50:1 motors (amsoil).  They have not converted me.

Answer 3

Sir,

Please accept any apologies you are due, I was the one who pointed out the 100:1 OMC outboards. Yes, I run my 15hp Johnson at 100:1, and while I am not up to date, it has provided years of reliable service. (knock on wood)

Misinformation is commonplace here in these forums, take answers and responses to answers with a grain of salt. I myself had my nose out of joint this morning and posted a question about a rogue here in the forum. After working hard to give spot on advice those "thumbs down" gnaw on me.

Anyway, nice follow-up. Will Yamaha continue at 100:1 or are they looking at a richer mixture? BTW, several of my clients run Yamaha 4-strokes and I think they are the best O/B out there right now.

Cheers.