gas/oil mix on 1966 Merc 60 6cyl twin

[66merctwin6cyl]

title says it all. trying to get the right oil/fuel mix. seems most mercs of that generation took 50:1, saw some post that as 3 oz oil (50 to 1 TCW III ). Is that correct?

we're thinking the fuel mixture might have had something to do with the engine shutting down after about four hours of stopping and going fishing on the river. hope it's not anything more. read otherwise about bad diaphram, bent impeller causing overheating, etc.

any advice appreciated.

 

[JB]

Re: gas/oil mix on 1966 Merc 60 6cyl twin

3oz oil??? What does that mean?

3oz TC-W3 to 1 gallon is 42:1. To get 50:1 use 2.56oz per gallon.

Really a lot simpler to run 48:1, which is one pint oil to 6 gallons of gas.

It is unclear what mix you are really running so we have no clue what your problem is. If you are putting 3oz TC-W3 in a tank with 6 gallons of gas it is a pure miracle that your engine has not blown up.

 

[66merctwin6cyl]

Re: gas/oil mix on 1966 Merc 60 6cyl twin

3oz oil??? What does that mean?

3 oz oil (50 to 1 TCW III )= 3 oz of TC-W3 per gallon of gas to get 50:1 ration, as some on this or other forums advise. I know it doesn't add up, seems some were "rounding up" to get the amount. no, we are not interested in blowing up a boat, thanks for your warm, heartfelt, i'm sure, concern. i did the math, too, and came up with 2.56 as well. Actually, I think the previous owner advised the boat owner, not me, to use the 48:1 ration, you mentioned, one pint oil to 6 gallons of gas.

Others were also advising to stay away from 30 weight motor oil. So, off we go to find TCW III.

Once we try that out, hopefully any performance problems will resolve.

 

[Fuzzytbay]

Re: gas/oil mix on 1966 Merc 60 6cyl twin

Ok more confusion, if you were mixing SAE 30, then the ratio should have been 24:1. Plus there would be performence issues. You have it right on the mix with TCW-III. Yet if it was still running SAE 30 for all these years, then by all means the carbs need a clean out, and the motor needs to be de gunked, ie seafoam treatment in the fuel, (or similar product) and deep creep down the cylinders as well.