Fuel and Lube Question

[bill-m]

I am currently using 100 LL aviation gas in my ’49 Mercury KF5 which I knock down to 90 octane with Coleman fuel. I use Penzoil two stroke oil at a ratio of 32 to 1. I use Quicksilver 90 Wt. gear oil in the gear box. My motor runs well on this combination and when I pull the spark plugs they are nice and clean and dry with a light tan color on the insulator. There is also minimal smoke. Aviation gas is more expensive but I get it free from a neighbor who has an airplane in exchange for fish that I catch.
My question is, would this combination work as well on the ’62 Clinton J-9 Apache that I recently aquired? As usual the manual says to use a good quality regular gas mixed at a ratio of 16 to 1 with a good quality 30 Wt. non-detergant motor oil. I think it would be ok but it would be reassuring to hear other’s thoughts on this. Thanks!

[outbdnut2]

I would use more oil in that KF5. I believe the manufacturer’s spec was 24 to 1. I’d go no higher ratio than 20 or 25 to 1. Yes your spark plugs are clean, but are your rings and bearings getting enough oil? You won’t know until they self destruct. So you may have to clean your spark plugs every 100 hours or so – that beats replacing bearings and rings. With the Clinton, and today’s TCW3 oils, I would go 20 to 1, but no lighter on the oil. Note that 20 to 1 is easy to measure too, because it’s a quart or liter of oil in a 5 gallon can of gas.
–
I’m sure you will get a lot more opinions on oil mix here. I am not a member of the "run as little oil as you can to save money, reduce smoke, and keep spark plugs clean" club for the reasons mentioned above. Oil is cheap insurance.
Dave

[westwind]

There is certainly no need to run leaded gas in either motor. The Merc is fully jeweled with needle bearings so it will be happier with less oil than the Clinton.

[mikesea]

Bill,
Lose the Ava gas and just try pump 92 or 87 which has more BTU’s. More heat greater expansion ratio = more torque.
Just food for thought my 2 cents.
Happy crusing
Mike

[bill-m]

MikeSea7, The reason I use Ava gas is because the manual says to use 85 octane regular or better. Out here all the regular has corn squeezins in it. The manual also said not to use premium auto gas because of all the additives. The Ava gas is low lead and does not have many of these additives. I will have to read the manual again which was written over 68 years ago. Your opinion on this would be greatly appreciated. Thanks!

[amuller]

Remember that 100LL avgas DOES have extremely toxic organic lead compounds (TEL) in it. I see no reason to expose oneself to this in outboard motor service. And Coleman fuel is even more expensive than AVGAS and probably gives you no benefit at all. (But I have no idea what the "octane" of Coleman fuel might be.) There is no advantage to using fuel with a higher octane number than needed to prevent detonation.

Around here (Minnesota) many gas stations sell no-ethanol "recreational" gas, but they are also starting to sell gas that is 15% ethanol, as opposed to the usual 10%. This is pure welfare for the corn growers and distillers. Whether it will cause a new set of problems remains to be seen.

I’ll say no more about oil mix ratios except that Clinton tended to specify a lot of oil.

[Anonymous]

Mercury changed the amount of oil needed for motors made after WW2. All of these were full jeweled and Mercury said to use a 50 to 1 ratio of TCW3 Mercury oil. In the Merc gear case use John Deere corn head grease. The original seals were not made for the use of 90w gear oil.

[frankr]

Concerning "additives", it is my belief that today’s unleaded gas burns a whole bunch cleaner than any of that old stuff. As for the corn, you are entitled to your own opinions on that. Lord knows everybody else has theirs. My opinion is all I ever use is regular pump gas, and have never had the first problem with it. Works for me.

[Pete]

No need for 100LL av gas these engines are low compression and run great on 87 pump gas, save you $$. I use (and suggest) E free on outboards & lawn equipment. As for oil ratio for a service engine that does fishing, idling, trolling, cruising, water skiing, etc 50:1 will do fine with a quality TCWIII oil. But it has been proven the higher the sustained rpm the more oil a 2 cycle needs. Oil ratio is a function of duty cycle, race outboards use a lot more for sustained rpms, same with 2 cycle sport bikes depends on how they are used like dirt, high speed track, etc . There is a practical limit on how much 2 cycle oil based on duty cycle use and the jetting and cylinder temp is part of it to get the best power output.

[bill-m]

Thanks for the input fellas, I will start using 91 octane premium gas in my motors.There are only two places in Wyoming to get recreational gas, Cheyenne and Casper, and I am a long way from both of those cities. I am using Penzoil TW3 oil and will continue to use 32 to 1 in my Mercury because the majority of replies suggested 50 to 1 and one reply suggested 24 to one. I will us 20 to one in the Clinton. As for the gear housing I will start using John Deare corn head grease. I am guessing I can get it at a John Deare Dealer which we do have here in Sheridan. Thanks again and if you think of anything else on this matter please let me know.

[Author]

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