TOPIC: synthetic in old motor no good??

had problems with my 62 Evinrude lark IV 40 HP this weekend. Ran bad. Did a compression test, 25PSI per cyl. Now I am told that old motors cant use synthetic oil in pre-mix. Really?? I am about ready to sell this whole boat/trailer . Had enuf of the hole in the water in which i dump hundreds...

By synthetic do you mean TCW-3? Or something else?

Peter
in Denver

As long as its TCW3 rated, its A-OK.

That's where I'm heading - and there's confusion about "synthetic" oils and TCW3 Oils...

Have run true 2-cycle synthetics successfully in my vintage outboards quite a few times with no issues at all. Klotz oil was one of them. Ya' gotta' love the smell of Klotz! Ran it in my drag racing days and what was left over went through my vintage fleet.
Didn't particularly like the way it "left" the engines, however. It would come out of the ehxaust in larger droplets than conventional oils would and left larger amounts of oil sheen on the water. For that reason I will only use conventional mineral or "dino" based lubricants now.

Your motor has been around for 48 years with all types of oils all of lesser quality than the OEM oils of today. I see no advantage of switching oils at this point. OMC XD30 oil will be just fine.

Howerver, 25 PSI is too low for an engine to run. Either your engine is wasted, you failed to open the carb while checking the compression or your gauge is junk.

Any chance you over heated the engine this past outing?

If you're mixing the oil at the proper ratio (as originally called for by the manufacturer of your motor) and you're using a TCW3 rated synthetic, then the cause of your low compression is not the oil.

It is VERY rare that both cylinders would read that low and equal, unless there is a commonality between them. Have you checked the head gasket? Otherwise, I would suspect your gauge or method.

I had it running in the river, and it seemed to only run 1/2 the normal RPM, or at least as half-fast as usual. I could have a bad guage, its old, a non-screw-in type. .Maybe fe4 i give up hope on her, i will get a screw-in type guage and check. No, i didnt have the carb open, either!I DID find I had a dulled,bent prop on her. So, lots of things could be wrong. How do i check for head-gasket problems>?

if it only has half power it may be only running on 1 cyl, do a thorough check of the ignition system.
Al

Running on one cylinder could also point to a bad head gasket. One telltale of a bad head gasket is water beading up on the spark plugs. I've also run into a couple motors this spring that had water in the gas (thanks to ethanol) and the water was fouling plugs, too.

If you confirm you have low compression, the first thing I'd do is remove the cylinder head for a look-see. Check the gasket, cylinder walls, piston crowns, etc. Looking for blown gasket (very obvious if that's the case), scoring on the walls, pitting on the crown, etc. Anything that looks out of the ordinary.

If compression checks out via a second gauge, start looking at ignition problems. Your "half speed" description is a classic 1-cylinder symptom.

- Scott

Bought a new compression tester today, and I have 90 pounds in each cylinder. So, thats GOOD! Raining now, so i havent been able to check spark. Will keep yall abreast of things as the weekend goes on.

also have great spark on both cylinders. havent had time to do much. Wondering if gas is bad? As soon as this nasty weather leaves, i will change gas and try on water again.

Changed all the gas, and new TCW3 Pennzoil synthetic oil. Mixed at 24 to 1. Put the boat in water Sunday, and it ran like a new one. Not sure why. Coulda been the other prop, or maybe the gas mixture. Anyway, its all good now! Thanks for the replys!!

Welcome to my "Old OMC" nightmare....

Some days mine(57 35HP Seahorse) runs like a champ, some days it runs like a bag of crap.

But it ALWAYS runs!

24 to 1????

I know the older engines.


But I would still run 50 to 1 just to be safe.

Hi; 50:1 is anything but safe in the old motors a much richer mix like 24:1 is safe for most 50's classics. When using synthetics in 57 and up 10 or more hp 32:1 is safe. I personally run Shell TCW3 oil at the original mix for all my vintage stuff including a jug of 8:1 for some of the antiques. The current TCW3 is so good compared to the old SAE 30 and 40 weight oils that I just can't justify the extra cost of the synthetic.
Al

The current TCW3 is so good compared to the old SAE 30 and 40 weight oils

which is why 50:1 or to err on the side of caution 40:1 is more than adequate for the old 50's motors

FWIW, ive been running my '57 at 40:1(recommended 24:1 with 30 weight) with el-cheapo Wally World TCW3 oil and have logged over 150 hours on it in the last year and a half...

Compression numbers were a mirror image of what they were a year and a half ago when i checked them last week and I see no obvious signs of wear to be found anywhere. If anything, id say the internals were even better looking than before(less carbon fouling, etc)!

I doubt 50:1 would hurt much of anything but do so at your own risk...but i can assure you, 40:1 is perfectly safe.

Many years ago, maybe '06 or '07, Frank Robb, a retired marine mechanic and j-rude whiz, performed a controlled experiment using straight tcw3, and synthetic mix, and straight synthetic. The straight synthetic won hands down for less smoke and better mileage. Maybe something else too, I dunno, it's early. After reading Frank's results, I went out and bought a gallon of synthetic tcw3. Less smoke and better mileage works for me, and my understanding of how synthetic coats the interior of an engine also sells me on it. Then again, I run synthetic oil in my two daily drivers and my hot rod. I can't see cheapin out on the vehicles I love.

I also run 93 octane in my '63 Merc.

Frank

MadProps wrote:

The current TCW3 is so good compared to the old SAE 30 and 40 weight oils

which is why 50:1 or to err on the side of caution 40:1 is more than adequate for the old 50's motors

ABSOLUTELY NOT!! 50:1 is NOT more than adequate for 1950s motors! It might work in some motors that have full ball and rollers, but most 1950s motors do not fall into that category. The extra oil does more than lubricate - those old motors are built with very loose tolerances and the extra oil helps seal between crankcase chambers, as well as old seals. On plain bearing motors (found on 7.5 & under models, and partially on some larger ones) the oil also acts as a cushion, too. The blanket statement that 50:1 is fine for all 1950s motors is simply not true. What works for a 1959 Evinrude Fat Fifty will not work with a 1956 Evinrude 7.5. If you know your motor's internals and how it was built, then feel free to experiment with leaner mixtures. Otherwise, it is best to stick with the 24:1 mix...

Another item often overlooked was the fact that thermostats didn't become the norm 'til the very late 1950s/early 1960s and that played a part in the eventual switchover to 50:1, too for OMC.

Chinewalker wrote:

MadProps wrote:

The current TCW3 is so good compared to the old SAE 30 and 40 weight oils

which is why 50:1 or to err on the side of caution 40:1 is more than adequate for the old 50's motors

ABSOLUTELY NOT!! 50:1 is NOT more than adequate for 1950s motors! It might work in some motors that have full ball and rollers, but most 1950s motors do not fall into that category. The extra oil does more than lubricate - those old motors are built with very loose tolerances and the extra oil helps seal between crankcase chambers, as well as old seals. On plain bearing motors (found on 7.5 & under models, and partially on some larger ones) the oil also acts as a cushion, too. The blanket statement that 50:1 is fine for all 1950s motors is simply not true. What works for a 1959 Evinrude Fat Fifty will not work with a 1956 Evinrude 7.5. If you know your motor's internals and how it was built, then feel free to experiment with leaner mixtures. Otherwise, it is best to stick with the 24:1 mix...

Another item often overlooked was the fact that thermostats didn't become the norm 'til the very late 1950s/early 1960s and that played a part in the eventual switchover to 50:1, too for OMC.

Chinewalker I'm running a 1965 65hp Merc at 40:1, I respect your opinion and would like to hear your thoughts. Thanks in advance.

Dan

Hi Dan,
Your Mercury was rated to run at 50:1 from the manufacturer in 1965. Running it a little fat won't hurt anything and may help with old seals and such, although I would recommend that you do an occasional de-carboning using something like Seafoam Deep Kreep or Power Tune from Quicksilver (Mercury).
- Scott

Dan, those old mercs want hi test gas too!

Frank

Thanks Scott I'll try the Power Tune.

I agree Frank not sure about the States but in Canada the only gas that I know of that is ethanol free is Shell Gold so that is what I run in my boats, thanks.

Dan

i didn't know any gas was ethanol free. i use 91 octane and 37.1 mix. tim c. told me when i got my rig that that was the safest way to go. it does smoke a little but doesn't faze me at all. are there any other gas that is ethanol free?

Chinewalker is correct. Mix the ratio according to the bearings. Plain bearing motors should be no leaner than 24:1, full roller motors OK at 40 or 50:1, depending on age. Run my motors with Pennzoil full synthetic, with an occasional shot of Seafoam to keep things clean. And the Pennz is 100% biodegradable, which keeps the tree huggers happy.

When you say "full rollers" Kerry, do you mean needle bearings like in my '63 Merc 1000?

Frank

For alcohol free fuel in your area, go to pure_gas.org and enter your zip code for the nearest station to you. That is all I run in my vintage engine fleet, my Whaler, as well as my lawn equipment. Hassle free when it comes to all flexible fuel components. As far as fuel oil ratio in the old plain bearing engines, my thinking is that there are only so many vintage and antique outboards out there and there are less every day. Why risk an enjoyable day on the water to save a little oil?? Factory Engineers determined the safe ratios for these engines and it's just too easy to adhere to that and not worry. I seriously doubt that if someone tells you that you can run much less oil than recommended (that person) will step up to the plate and help foot the bill on repairs when your particular engine can't cut it on a lean oil mixture.

Pure-Gas.Org shows one station in Metro Denver. What irks me is that you can buy Ethanol Free everywhere in Iowa - a state that's responsible for our having to swallow this ethanol crap. I shudder to think what 15% will do to our motors.