Correct oil and lube for 1963 40hp Big Twin

[baytonemus]

I've been searching the forum for awhile trying to find what type of motor oil and gear lube I should use with this outboard. I don't have an owner's manual, although I guess that wouldn't list currently available products.

Also, I've read a couple of threads about whether or not to mix at 24:1 or a higher ratio such as 50:1. Thoughts?

Lastly, does anyone use an additive for cleaning such as Marvel Mystery Oil or similar?

Thanks!

 

[tx1961whaler]

Re: Correct oil and lube for 1963 40hp Big Twin

24:1, TCW-3 2 stroke oil. Synthetic will smoke less.
80-90W Marine gear oil for a manual shift gearcase; Type C gear oil for an electric shift.

 

[baytonemus]

Re: Correct oil and lube for 1963 40hp Big Twin

Thanks! Any concern about switching to synthetic oil after 40+ years of conventional?

 

[tx1961whaler]

Re: Correct oil and lube for 1963 40hp Big Twin

None that I know of. I switch back and forth between conventional, synthetic blend, and full synthetic 2 cycle oil with no issues. Synthetic switching only seemed to be an issue with some cars, and some of that controversy smacked of urban myth.

 

[rolmops]

Re: Correct oil and lube for 1963 40hp Big Twin

In 1963 OMC came out with an update for the fuel mix.They clearly stated that all engines with needle roller bearings are good to go on 1:50.
Your big twin does have needle roller bearings.1:24 is not going to hurt it(in fact you are supposed to use 30 weight engine oil),but it will do fine on 1:50