1963 oil mix 75 hp

[yorab]

I'm rebuilding my engine now so I'm scouring the forums for info. Even though I'm looking for info related to the rebuild, I still like to read up on other topics as well. I've come across slightly confilicting recommendations for fuel/oil mixtures for my motor. Some posts say that anything pre-1964 should run 24:1. Some say that the mix for the '63 75 hp can be 50:1. The fairly exhaustive article in the FAQ says 40:1. Of course I would like to know the correct mixture, but I would also like to know why the mix should be at the recommended ratio. The FAQ mentions jeweled engines. I'm not sure what that means. I am thinking that the engines were made of different materials at the bearing surfaces or the bearings themselves were made of different materials for different years, thus requiring different amounts of oil. Is this correct?

 

[tashasdaddy]

Re: 1963 oil mix 75 hp

i don't have a manual that covers your motor, so i'm not going to suggest the mixture. but you are correct in the thought that the bearings were made of different materials, is the reason for the different ratios. i do know that during your break in period on your rebuild double the amount of oil for the first 10 hours, it's going to smoke, but needs the oil, so everything seat correctly.

 

[JB]

Re: 1963 oil mix 75 hp

In 1964 OMC decreed that all pre-1964 OMC built engines use 24:1. That is the recommendation I would go with.

Some people run 50:1 and get away with it, some don't get away with it.

 

[BoatBuoy]

Re: 1963 oil mix 75 hp

From the Evinrude website:
"Q - What is the fuel/oil mix for my motor?

A - The following is generally true: 1958 and prior used 20:1, 1959 thru 1963 used 24:1, 1964 and newer use 50:1. High performance usage (racing) requires a ratio of 25:1. New engine break-in (not DI) requires 25:1."

http://www.evinrude.com/en-US/About.Us/FAQ/Oil.Fuel.htm?popup=true#Q2

 

[F_R]

Re: 1963 oil mix 75 hp

Putting all the opinions and whoop-la aside, the bottom-line truth is if you look at the parts list and specifications for the '63 and '64 they are the same. However, if I tell you to run 50:1 in your '63 and it blows up you will swear and be durned that the oil was the cause of it, and blame me for telling you it's OK. Therefor, it is a matter of you decide for yourself. BTW, I can show you a Johnson Service Bulletin that says to use 50:1---But only if you use Johnson/Evinrude oil. Hey, they gotta plug thier own stuff, right? Besides that, J/E oil is not the same stuff today as it was back then. Again, you decide.

 

[yorab]

Re: 1963 oil mix 75 hp

Well, I'll have to decide. I know that running the engine with insufficient oil will cause undue wear and failures. What would be the ramifications of running "too much" oil? Maybe I will go with a ratio between 50:1 and 24:1. Also, FR, I would never blame anybody if MY decision of oil mix led to some kind of failure of the motor. But I know how a lot of other people are (they blame everybody and everything besides themselves) and I realize that you are just trying to CYOA.

 

[tashasdaddy]

Re: 1963 oil mix 75 hp

too much oil it will smoke a little more, but the synthetics, don't smoke as bad. also having to clean or change plugs more often. decarb once a year, should be done anyway.

 

[steelespike]

Re: 1963 oil mix 75 hp

My info from a 50 year Evinrude dealer is 50:1 on all larger motors back to
1960.I know I read somewhere that the 58 V4 fat fifty was 50:1 mix.

 

[JB]

Re: 1963 oil mix 75 hp

Here we go again. Smart alec know-it-alls think they know more than the people who designed and built the engine.

OMC said 24:1, they always said 24:1. Evinrude (BRP) says 24:1. Anyone wonder why they said that??

Yes, you can use 50:1 but do it at your own risk. Heck, if you want to take the advice of KIAs you can use 100:1.

 

[Don S.]

Re: 1963 oil mix 75 hp

I've also hear that, that vintage motor should be run on 24:1. IIRC wans't it due to the fact that some of the older motors didn't use berings. They used used sleeved berings instead. please correct me here if i am wrong.

 

[Scaaty]

Re: 1963 oil mix 75 hp

Ya got rollers on the small rod ends, ok..50..bushings..?24 (but run 24 anyway..new oils run super clean)JMHO

 

[yorab]

Re: 1963 oil mix 75 hp

Okay, I'm really leaning toward 24:1. Now, after my rebuild should I run 12:1 as per the requirement to double the amount of oil for break-in? This seems like an awful lot of oil to be mixed with the fuel.

 

[angus63]

Re: 1963 oil mix 75 hp

At 12:1 you'll have no problems with flying insects, but you may have to rename your vessel "Exxon Valdez II". Stick with 24:1 in my opinion, just stay below 1/4 throttle for first hour, below 1/2 throttle for next two hrs., and only short bursts of WOT until you have about 10 hrs.
Good luck

 

[yorab]

Re: 1963 oil mix 75 hp

JB, you seem to be well informed (and adamant) about the 24:1 ratio. Do you know what mix is recommended for the rebuilt engine break-in on an engine that normally runs 24:1?

 

[JB]

Re: 1963 oil mix 75 hp

I don't have any documentation on that, yorab, but I tend to agree (opinion only) with angus.