Using synthetic 2 cycle oil in older engines??

RiverRock

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Aug 9, 2012
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Anyone have any experience or knowlege in using a synthetic 2 cycle oil in older engines. Basically I'm wondering if it's a good idea to run a "modern" oil in an older engine. Does an older engine require a heavier oil (tcw 3) for lubrication? or will the newer synthetic oil provide plenty of lubrication etc etc...
The engine I'm thinking of using a synthetic in is a 1973 Johnson 9.5

Thanks.
 

Lk40hp

Petty Officer 3rd Class
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Aug 22, 2012
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Re: Using synthetic 2 cycle oil in older engines??

I use non synthetic in my 68 40hp, and 18hp. Never had a problem, but personally I like to mix it a little thicker, being its older. That's my .02 worth.
 

Rick.

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Re: Using synthetic 2 cycle oil in older engines??

I think the synthetics are better than conventional but I'm not saying they are necessary. Any good quality TCW-3 oil will do the job if mixed properly. I have heard synthetics are biodegradable so I bought some and it doesn't say anything on the label about it so I'm thinking it isn't true or at least not true for the product I bought. Rick.
 

RiverRock

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Re: Using synthetic 2 cycle oil in older engines??

I think the synthetics are better than conventional but I'm not saying they are necessary. Any good quality TCW-3 oil will do the job if mixed properly. I have heard synthetics are biodegradable so I bought some and it doesn't say anything on the label about it so I'm thinking it isn't true or at least not true for the product I bought. Rick.

From the things I've read about synthetics, they are supposed to be better to run in outboards. The engine I have is a 73' and has very low hours and is in mint condition. I want to run/use the best products through it to prolong it's life the best I can, with proper maintenance as well of course, but my concern is if the synthetic oil is ok to run through an older engine?
 

aerobat

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Re: Using synthetic 2 cycle oil in older engines??

synthetics burn off better, lubricate better, carbon buildup is lower, less visible smoke. there is no reason not to run in an older engine. but the engine does not need such oil, and the thruth is that in 1973 the best available oil was worse than the cheapest TCWIII today.

the only thing you should not run are synthetics specially designed for direct injected engines. ( e.g xd100 )
 

F_R

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Re: Using synthetic 2 cycle oil in older engines??

I don't consider a 1973 to be old. Here is all I've used for the last several years. Note that it does say Biodegradeable on the label, right above where it says NMMA TC-W3. More importantly, it smokes much less. My motors range from 1937 through 1984. Right now, my main problem is finding it at a reasonable price. Wal-Mart used to sell it, but doesn't seem to have it any more.

EDIT: I should mention iboats sells a Synthetic Blend oil that should be good also. That's probably where I go next time.
 

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Haffiman

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Re: Using synthetic 2 cycle oil in older engines??

The 2-strokes using 2% mix, needle bearings on crank and piston pins, may use synthetic as they are not dependable on film thickness but more on film strength which in most cases are considerable better in the synthetic oils.
 

yorab

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Re: Using synthetic 2 cycle oil in older engines??

I wonder to what degree these are truly biodegradeable. I haven't thought much about this before, but if there are biodegradeable oils available, then I'd definitely prefer to use these. I almost get sick every time I see how much unburned fuel/oil mix my old motor puts into the water.
 

tin knocker

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Re: Using synthetic 2 cycle oil in older engines??

Too keep from getting almost sick console yourself with the fact that oil cannot go into the water, it can only float on the surface.
 

Tim Frank

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Re: Using synthetic 2 cycle oil in older engines??

Too keep from getting almost sick console yourself with the fact that oil cannot go into the water, it can only float on the surface.

If that were actually true, the English language would not need the word "emulsion". :eek:;)
 

82rude

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Re: Using synthetic 2 cycle oil in older engines??

I wonder to what degree these are truly biodegradeable. I haven't thought much about this before, but if there are biodegradeable oils available, then I'd definitely prefer to use these. I almost get sick every time I see how much unburned fuel/oil mix my old motor puts into the water.
try g-oil. its 100 percent bio,and if i remember correctly is made from cow tallow.i used it in my 90 evinrude for 2 years and loved it.i currently have a 60 etec and use xd-100,the only way you know that thing uses oil is to pay attention to the oil resivior!
 

Chris1956

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Re: Using synthetic 2 cycle oil in older engines??

Actually the real polution problem with carb 2 cycle motors is unburned hydrocarbons that are pumped into the water with the exhaust. The oil is not the biggest poluter. That is why the DI Motors pass the polution standards. DI motors burn fuel more completely, and release automobile-like exhaust gases, plus some unburned 2 cycle oil into the water.

Getting back to the OP qustion. Synthetic 2 cycle oil is not necesssary to run in your motor. Any TCW-III 2 cycle oil is fine. Mix both at 50::1. It is not necessary to use more oil, just don't use less oil in the mix.
For the record, I used some really expensive synthetic TCW-III oil in my speedboat, for a whole season. The difference in smoke and smell from the Wallyworld dino TCW-III was minimal or non-existant. just my observation......
 

kfa4303

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Re: Using synthetic 2 cycle oil in older engines??

I don't consider a 1973 to be old. Here is all I've used for the last several years. Note that it does say Biodegradeable on the label, right above where it says NMMA TC-W3. More importantly, it smokes much less. My motors range from 1937 through 1984. Right now, my main problem is finding it at a reasonable price. Wal-Mart used to sell it, but doesn't seem to have it any more.

EDIT: I should mention iboats sells a Synthetic Blend oil that should be good also. That's probably where I go next time.


I like this stuff too. It's usually about $20 a gallon at Wally world when you can find it. I get very little, if any, smoke except upon start up even running 24:1 in my '66 20 hp.
 

RiverRock

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Re: Using synthetic 2 cycle oil in older engines??

synthetics burn off better, lubricate better, carbon buildup is lower, less visible smoke. there is no reason not to run in an older engine. but the engine does not need such oil, and the thruth is that in 1973 the best available oil was worse than the cheapest TCWIII today.

the only thing you should not run are synthetics specially designed for direct injected engines. ( e.g xd100 )

These are the things I was hoping to hear and some of the reasons I'm wanting to run synthetic oil through my engine. I just wanted to be sure that it's ok to run a "modern" oil through an engine made in 73'
Thanks everyone for the replies and good information!
 

aerobat

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Re: Using synthetic 2 cycle oil in older engines??

enjoy !

and even think a minute about your mixing ratio using modern synthetic oils-remembering that the recommended ratio for your engine was chosen in the 70` with the oils available in those days . todays synthetics dramatically outperforms these old brands so less oil is the better choice.
 

Rick.

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Re: Using synthetic 2 cycle oil in older engines??

enjoy !

and even think a minute about your mixing ratio using modern synthetic oils-remembering that the recommended ratio for your engine was chosen in the 70` with the oils available in those days . todays synthetics dramatically outperforms these old brands so less oil is the better choice.
I wondered if someone would bring this up. I have read the Machinist uses a leaner mix of synthetic than 50/1 but not sure how he arrived at his mix rate. Rick.
 

tanuki

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Re: Using synthetic 2 cycle oil in older engines??

enjoy !

and even think a minute about your mixing ratio using modern synthetic oils-remembering that the recommended ratio for your engine was chosen in the 70` with the oils available in those days . todays synthetics dramatically outperforms these old brands so less oil is the better choice.
I agree that today's synthetics outperform the old brands with the "same" ratio of oil used in the 70's....but why would you "default" back to 70's performance by using less synthetic now?
(BTW I use Pennzoil synthetic blend in my 1975 Rude 9.9)
 

Haffiman

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Re: Using synthetic 2 cycle oil in older engines??

Oils in 2-strokes have 2 main functions.
1: Lubricate while running.
2: Preserve when not running.
The first may well be achieved by reducing the mix ratio to 1% by using modern oil, and was the reason for the, short lived, recommendation of 1/100 by OMC.
The second however is a different story. The amount of oil left to preserve internal parts when engine not used gets on the risky side if reducing the mix ratio. If using the engine daily and in fresh water, most likely you may even reduce the mix ratio. However with more random use, once a week or even longer intervals, stay with the 2% ratio whatever 'quality' you use. Today's fuel with its alcohol mix attracts moisture and increases the risk of corrosion and storage damage.
 

aerobat

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Re: Using synthetic 2 cycle oil in older engines??

I agree that today's synthetics outperform the old brands with the "same" ratio of oil used in the 70's....but why would you "default" back to 70's performance by using less synthetic now?

i do not think you go back to default performance, quite the opossite. modern oils for 2strokes are able to mix up with fuel better than the old ones and give fully protection using a thinner oil film on the parts that need lubrication. beyond the aspect they burn off better with combustion, using a lesser amount of them further improves characteristics on trolling, carbon buildup and smoke.

we have to understand that when the engine is "fully" lubricated a further increase of oil will not give more lubrication and engine health but will give the negative aspects of carbon buildup, spark fouling etc etc.


haffiman is right that oil is also needed to preserve when not running- further the old engines may have a more poor corrosion protection than new ones-so finally he is right that it also depends on characteristics of usage of the engine . but also here modern oils with a thin but solid oil film outperform the old ones in corrosion protection.

cheers
 
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