TOPIC: Poll: Fuel, Oil, Engine?

Im sure this has been addressed at some point but a quick search didn't yield any results of note.

What kind of fuel do you use in your vintage outboards, 50's and 60's particuarly.

What engine?
what fuel? 87? 89? ethanol free?
Oil? regular TCW3? synthetic?
Ratio? 24:1 40:1 50:1?

I am no expert but from my experience and others comments I believe one should run Premium as most premium has no Ethanol in it. The Ethanol can attack brass and rubber parts in the fuel system over time if they are not made to withstand Ethanol. As for oil, the oils of today are so far superior to the oils back when these vintage motors were made , I don't think you can go wrong with almost anything available today mixed at the manufacturers recommendations.. One mans opinion...Brad

My mechanic recommended the same thing Meteor stated. 1955 evinrude 15hp Auquasonic and 1965 Merc 1000 (100hp)...Dad bought the evinrude new and the Merc was owned 50 years by original owner. I still run my 1978merc 20hp I bought in high school...maybe because each of us original owners had to work hard for this extra money, we just really wanted them to last...and Dad taught me to take care of my stuff...use it plenty as you wish, but learn all you can so you know how to take care of it and your investment will serve you a long time. My grandkids will be 5th generation with the 1955 rude and 1956 Starcraft 14 we still have. I never run ethanol fuel.

1965 Mercury. 1000, only premium/ no ethanol. In Wisconsin, by lake areas, or in marinas, easier to get than in Illinois. We use 50 to 1 of Mercury brand oil. We do add some stabilizer every so often like Starbright etc. With the 100 hp, we don't exactly have tankfuls hanging around too long before it's used up. $$$$$

The older motors, late 50's should run 26:1.

How about a 1966 mercury 350 35hp?

My Merc Manual has a foot not under the Master Spec chart that says "All 1963-1969 Mercury Models use new FORMULA 50 Quicksilver 2-Cycle Motor Oil, mixed one 12 oz. can with 5 gallons of gasoline"... (so if my math is right - that is 53 to 1...but people said it was referred to as 50 to 1)... then it goes on to say "All Mercury Models use Formula 2 Quicksilver 2-Cycle Motor Oil, mixed 12 oz. can with each 2 gallons of Gasoline" ...my assumption is that was an older oil formula. I have used modern Merc oils at 50 to 1. I am thinking the chart on the side of the gallon oil jug actually says something like 2.5 oz per gallon (which is only actually 15 oz for 6 gallons, so 51.2 to 1, yet I am thinking it is common to use 16 oz. per 6 gallons, which is 48 to 1)...Experts or mechanics should chime in. I am just an old boater with a manual and lots of gas and oil mix behind me. I am thinking that a bit too much oil might cause a bit more smoke, but too little oil "smokes" (blows) the motor. My Dad always made sure we were always 100% sure we knew we had added oil, or it did not get burned in the outboards. Hope this helps. Added note: Full Throttle Range is listed at 4,800-5,200 RPM...J6J plug gapped at .025" (I believe you have to find an equivalent plug unless you have god originals as I don't believe that J6J is made any more)

Mercury Bulletin Number 80-6:

"A. USE OF FORMULA 50-D OIL IN OLDER MERCURY OUTBOARDS

Formula 50-D oil can be recommended (at a 50:1 mixture) for use in earlier Mercury outboards regardless of year of manufacture.

Formula 50-D also can be used in other brand outboards (at a 50:1 mixture), provided that the manufacturer recommends use of a 50:1 oil mixture."

The above was copied verbatim from a Merc Service Bulletins Microfiche.

Since this bulletin was issued over 30 years ago, I'd expect that Mercury's latest oil formulations (and any good TCW3 oil for that matter) would be far superior to the Formula 50-D oil.

If anyone has any information where Mercury subsequently changed or rescinded the above recommendation, please post a reply so we'll know.

A caveat to the above would be that this recommendation was made for production motors. If you are racing or operating a "racing" motor, you of course should run a much richer oil mix.

Just to add a bit more context, older (mostly 50's and prior) outboards that aren't "fully jeweled" i.e. don't use roller, needle or ball bearings on every rotating surface in the powerhead and may use some or all babbitt/bronze bushings, will typically require a much richer mix.

For example, a 50's Johnrude 5.5 hp and 7.5 hp have no "jeweled" surfaces so they must be run with a rich oil mixture, typically 24:1 or you'll get internal damage. My old Champion Blue Ribbon, as I recall, says either 16:1 or 12:1 on the instruction plate. Pretty rich!

If you use a quality oil it shouldn't smoke too much, even at very rich ratios. There are a few oils out there marketed as "smokeless" so that's an option.

I run non-ethanol regular unleaded fuel only in all my outboards and other small-engine-powered equipment. Fortunately there's a Cenex 10 minutes away that sells the stuff and I run it in my Nissan PU as well. It runs better and gets better mpg.

If you have a higher-performance engine and can get premium non-ethanol, by all means use it. Most other engines will run fine on 87 octane straight fuel. Any OMC V4 except for high-compression 135's and 140's will run great on 87 octane. Better use Premium on those or get the low-compression head gaskets! Doc Frankenmerc likes to run Avgas 100LL in his hot Mercs, so that's another option if you have a pilot buddy and you're near a local airstrip.

Mercury doesn't recommend use of Premium ethanol-blended fuels, because typically there are a lot of additives and extra alcohol involved in bringing the octane up and these things aren't conducive to the longevity of the engine.

With newer high-performance 2-strokes, it's probably better to follow the mfr's recommendations as far as the brand & type of oil to use. Most any of the older motors would be very happy with a synthetic or synthetic blend. I was using Penzoil synthetic blend for quite a few years but Walmart stopped carrying it. So I get either Merc or OMC synthetic or synthetic blend since Wally's now carries those.

Merc Premium Plus synthetic blend is a bit more than the regular syth. blend, but it has more cleaning additives and will keep carbon buildup down. Or run some Seafoam, Evinrude Johnson Carbon Guard, Gumout Regane, or other quality carbon cleaner thru the fuel system at least a few times a year.

I run stabilizer in all the fuel unless it's going to be burned right away. Stabil Marine or Star-tron work well. Briggs & Stratton sells a stabilizer that's good for up to 3 years with the right dosage. Don't think I'd try that long of extended storage with alcohol-blended fuel, though! If you can only get alcohol fuel, better run a stabilizer all the time. Even alcohol residual will cause corrosion issues sitting in the fuel system between runs. Better off, don't use it! Most of the older motors I'm working on have a lot of fuel problems due to alcohol. The stuff is a nightmare if you're a customer and a boon for mechanics!!

Cheers..................ed

Thanks Ed for all of that expertise. I was hoping you could add much more than I could offer. I just learned a bit more thanks to the good questions asked in this thread!

If you can get gas without ethanol, good for you. In California, virtually all gasoline contains ethanol but with Sta-bil ethanol treatment or the full marine stabilizer plus version older two strokes seem to do ok. I always use premium (91 octane) because the ethanol will absorb water from the air (even with minimum exposure, over time) and that will reduce the original octane level. Go with any TCW3, modern oil composition is so much better than the old days. For really old two strokes 24:1, 50:1 for late 60s engines and newer or go with a half way mix to be sure and let it smoke a little. Anyway, that's been my experience.

If your fuel system is in good shape, with current issue hoses, ethanol resistant carb kits, etc. you are fine with the ethanol enriched fuels. If you plan on leaving the tank for more than a few weeks, add a stabilizer to prevent phase separation. Or, use a sealed tank to prevent humidity from affecting the fuel. I run 87 pump gas in all my outboards with no ill effects. If you wish to spend the extra on premium, you won't hurt anything, but I don't think it's necessary.

I agree with Ed. Ratios should be followed religiously for older motors. All that oil is why they are still running, especially the plain bearing motors. I use full synthetic oil for all of my old outboards and my lawn and garden equipment. I also use regular gas with Seafoam added to everything. In the fifteen plus years I have used it, not one carb rebuild or fuel line issue. I buy it by the gallon.

I'm running a newer Honda for fishing. I had problems with the ethanol content. The stock Honda primer bulb was putting small chunks into my carb. I kept cleaning the system and carb and it would come back after a short time. I was using a conditioner. Honda insisted the hose was the problem. I replaced it again. Out of desperation I cut the primer bulb and run a finger into it and it came out black. Called Honda again and they basically called me a liar. I have a few older outboards but have not used them. This damn Honda sips gas.

So how do you know that the primer bulb degradation was caused by ethanol? Just curious.

I run ethanol free in my '73 Evinrude. I figure better safe than sorry and I can get easily around here for not much over E10 cost. I also run only Evinrude brand (nonsynthetic) oil at 50:1, premixing it myself in the tanks. Brand shouldn't make a difference as long as the oil meets the standards BUT.....it seems like cheap insurance given the cost of a motor.