Oil Mix for big twin

[ryendube]

K so I need some real life experience advice, not this what its specced for etc...

I know it says 24:1 but thats antique oil and gas. I remember tryin it when I first got it at 24:1 and it wouldnt start. Engine guy told me use 50:1 I do and it runs great. Ive even read with the use of top 2stroke oil you can run 100:1 with no problems and have read here all sorts of ratios.

Now I use mid grade gas and Ams oil not the crazy interceptor gold stuff but the 2nd best stuff. ( i use the interceptor for the jetski 1100cc triple)

Now Id love to hear from anyone who has owned one of these for a time or anyone who works on them.

Grade of gas type of oil and ratio.

 

[Bifflefan]

Re: Oil Mix for big twin

guessing you need to let everyone know what the engine is and also the year. All the ratios you mentioned are ones that are still used. But it all depends what you are using them in.

 

[ryendube]

Re: Oil Mix for big twin

guessing you need to let everyone know what the engine is and also the year. All the ratios you mentioned are ones that are still used. But it all depends what you are using them in.

umm dammit, you guys are supposed to guess and give me an exact answer....


1957 Evinrude 35hp.

 

[lindy46]

Re: Oil Mix for big twin

I have a '57 Lark 35hp and mix 24:1 - don't plan on taking a chance with anything else. Regular 87 octane gas.

 

[Chris1956]

Re: Oil Mix for big twin

Ryan, it is likely that '57 should use 24::1 due to it's design. You might PM Joe Reeves and see what he recommends. He is an expert on those oldy/goody

 

[ryendube]

Re: Oil Mix for big twin

I have a '57 Lark 35hp and mix 24:1 - don't plan on taking a chance with anything else. Regular 87 octane gas.

what type/brand of oil

 

[coolguy147]

Re: Oil Mix for big twin

what type/brand of oil

tcw-3 oil from walmart will be fine sythetic will smoke less

 

[rjezuit]

Re: Oil Mix for big twin

The motors of that vintage had plain bearings (bushings) in many of the spots(wrist pins etc). They later went to roller bearings. If you don't care about the motor being around a lot longer, the 50:1 of a new oil will work, but wear will be greater and you will burn up the bushings eventually. If you want to keep it around stick with the 24:1 either semi synthetic or synthetic. 1957 is right at the cusp of where they started converting. If you know for a fact it is all rollers, you are probably okay @50:1, if not 24:1. Rick

 

[R.Johnson]

Re: Oil Mix for big twin

This question goes round, and round on this forum with no real answer. The other day I was looking at a boating magazine, and there was a question about the new E-Tek engine. Seem's it can be programed for tw-3, or synthetic oil. Must be a difference? I have been away from the newer engine's, so I was not aware of this.

 

[JB]

Re: Oil Mix for big twin

There is only one correct answer. Anything else is the result of risk taking and/or elitist mythology.

All OMC-made engines of the 50s, and up through 1963, use a 24:1 mix. All after 1963 use 48:1 or 50:1. That is what OMC said and that is what BRP says.

Any TC-W3 rated oil will do just fine; synthetics smoke less, make less carbon and cost a lot more.

87 octane unleaded regular is quite satisfactory. There is no benefit from using higher octane except maybe a bit of a brag factor and a lighter wallet.

EDIT: Well I stand corrected. There are several answers, depending on what OMC or BRP publication you read. I still say 24:1 for a '57 Big Twin

 

[tmcalavy]

Re: Oil Mix for big twin

Run it at 50 or 100:1 and you'll make a big, useless boat anchor out of it...don't do that to that fine motor.

 

[R.Johnson]

Re: Oil Mix for big twin

If synthetic smokes less, and cost more, why would they have to program the engine? If you were to check, many thing's that did not work in the 50's is taken for granted today. If you had a classic 50's car, would you use 50's oil, or would you go again'st the manufacture's recommendation? There is an alful lot of " I never tried it, but I know it won't work" on this board. My son, and I have been running 50-1 in our 57, 58 18's for the last 10 year's. You would think they would break pretty soon. I'm not telling anyone to do this, just don't come back, and tell me it won't work.

 

[JB]

Re: Oil Mix for big twin

I agree with RJ to this extent: OMC outboards from the 50s will tolerate a lot of abuse for a long time. For a 50+ year old engine 10 years is not much.

That includes running high detergent motor oil and 80 octane heavily leaded gas in mixes as rich as 8:1 or as lean as 100:1.

That they will tolerate abuse is no reason to abuse them.

 

[jay_merrill]

Re: Oil Mix for big twin

I have a pair of 1958 ERude Bigtwin 35hp motors that I ran on Pennzoil semi-synthetic (TC-W3) @ 50:1 for years. They still run just fine.

The person who advised me to do this, is the owner of an Evinrude dealership. He has been an authorized OMC/BRP service center for over 30 years.

The key to being able to do this seems to be in whether or not the motor has needle bearings. If it has them, you can go with 50:1, as long as you use a quality oil, which means TC-W3 as a minimum. I would not, however, run the motors on anything thinner than 50:1 and my personal preference is to run at least a semi-synthetic oil.

 

[cougar1985]

Re: Oil Mix for big twin

in all my old omc,s i run full syn at 24 to 1.these are all pre 58 models.ive never had fouling problems or excessive smoke problems atall.

 

[Chinewalker]

Re: Oil Mix for big twin

With the old OMCs, there is a second consideration to use when determining whether to go 50:1. In addition to bronze/plain bearing vs. needle/roller bearings, there is also the fact that they started adding thermostats to their motors in the late 1950s. This allowed the internal tolerances to stay more consistent at operating temps, which in turn allowed the oil ratio to be leaned out to 50:1. Non-t-statted motors can have some significant variance in tolerances, which is where the extra oil can help.

For the most part, I adhere to the manufacturer's cut-off at '63/'64, but I do lean the mix on some models if they have the thermostat... Not to 50:1, but maybe 32:1...

- Scott

 

[jay_merrill]

Re: Oil Mix for big twin

For whatever it is worth, the late fifties Bigtwins don't have t-stats.

 

[jbjennings]

Re: Oil Mix for big twin

K so I need some real life experience advice, not this what its specced for etc...

I know it says 24:1 but thats antique oil and gas. I remember tryin it when I first got it at 24:1 and it wouldnt start. Engine guy told me use 50:1 I do and it runs great. Ive even read with the use of top 2stroke oil you can run 100:1 with no problems and have read here all sorts of ratios.

Now I use mid grade gas and Ams oil not the crazy interceptor gold stuff but the 2nd best stuff. ( i use the interceptor for the jetski 1100cc triple)

Now Id love to hear from anyone who has owned one of these for a time or anyone who works on them.

Grade of gas type of oil and ratio.

Just for clarification, there is no way that your motor wouldn't start because you were running 24:1 instead of 50:1 mix.
I run mine 24:1 and would not knowingly purchase a 50's motor that had been run at 50:1. I've got a couple of the 50's motors that I've worked on and the only one that I'm not satisfied with, the owner said his son ran it at 50:1. It was a '55 10hp and had a lot of scoring and scuffing on the cylinders. It still runs, just not as nice as it should. Your motor may have all roller/needle bearings (I'm not sure) but it is still 52 years old. I'd give it the full 24:1 just because of all those years of wear.
JMO,
JBJ

 

[ryendube]

Re: Oil Mix for big twin

Just for clarification, there is no way that your motor wouldn't start because you were running 24:1 instead of 50:1 mix.
I run mine 24:1 and would not knowingly purchase a 50's motor that had been run at 50:1. I've got a couple of the 50's motors that I've worked on and the only one that I'm not satisfied with, the owner said his son ran it at 50:1. It was a '55 10hp and had a lot of scoring and scuffing on the cylinders. It still runs, just not as nice as it should. Your motor may have all roller/needle bearings (I'm not sure) but it is still 52 years old. I'd give it the full 24:1 just because of all those years of wear.
JMO,
JBJ

K how about we ask this, can we all agree that synthetic oils are superior to reg oils? that they lubricate far better and do not breakdown like reg oils do?
So running a leaner mix with a synthetic can give the same protection as a richer non synthetic.

oh also Im getting responses of 50:1 for my motor because it is bearing not bushing your older smaller 55 10hp is not so from what im understanding 50:1 is NOT acceptable.


the whole starting thing is true granted I may have mixed up the gas can with an older one but I swear it happened to me before cause whan i first got it I used the labeled mix. It just cranks and cranks with the reg 24:1 mix soon as i swapped the tanks (have 2) to the 50:1 synthetic it ran mint. Now once i was out on the water i swapped again and it ran well with the. 24:1 no difference but at start the 50:1 it fires right up.
Im going to try again this weekend with fresh gas the boys up there may have been messing around woth the gas cans, dupping old gas in them.

 

[JB]

Re: Oil Mix for big twin

K how about we ask this, can we all agree that synthetic oils are superior to reg oils? that they lubricate far better and do not breakdown like reg oils do?
So running a leaner mix with a synthetic can give the same protection as a richer non synthetic.

Absolutely not. Synthetics probably lubricate better, make less smoke, stink and carbon and are generally biodegradable. That is it. Oh, and they cost a lot more.

The notion that they can therefore do an acceptable job in leaner mixes is not logical.