This is for Fr. Frank

[seacraft76]

I was reading you earlier post talking about the 1983 115 inline 6 and all the advice you gave that member,
I own and 1984 115 hp in-line 6 in great shape with low hours,i would like some advice please
right now i am using omc tcw 3 because i had an evinrude before at 50-1 is this oil ok? reason is i heard that pennzoil is sometimes used for the merc's , and should i drop down to 40-1 like you advised the other member i usually like to go fast it has a 13 1/4 x 17 prop spinning 5400 rpm tops
also i always put in the 87 octane , i recently put in a trim and tilt and will be testing that tomorrow, i would like to take care of this engine as it runs great thanks

[Fr. Frank]

The OMC oil is good. I have two Mercury motors, and I run the Premium Quicksilver synthetic blend oil. I don't recommend off-brand oils, but Pennzoil is good, considering that they actually make the OMC 2-stroke oil to BRP's specs. Quicksilver oils used to be made by Texaco, but I believe Chevron now makes them to Mercury's specs. BTW, TCW-3 is a minimum standard for oil, not a guideline. But not all motors can use TCW-4.

As to the gas-oil ratio, if you run above 4800 rpms more than you run below, you should mix 40-1, and if you constantly run in the 5600-6100 rpm range (or higher) go one heat range colder with your plugs to avoid detonation. (The price more that doubles for the different plugs, and you'll probably have to special order from a marine racing supply company. For instance, the Denso SF51 plug retails locally for $8.42, as opposed to the SF50 for $3.77)
If you continue to run just the stock carbs and mostly below 5600, just run the BUHW plugs from NGK, or the SF50 from Nippon-Denso. I prefer these to Champion for quality control reasons. If you have to go with a colder plug, go with the Denso brand.
If you run mostly below 4800, mix at 50-1. If you have the original carb jets, never mix heavier than 40-1, or you'll end up leaning out your fuel-air mixture, and risk blowing the motor. Racing applications mix at 36-1 or 24-1, but they run larger jets to avoid lean conditions. The downside to that is horrible economy.

Hope all that helps.

[seacraft76]

Thanks for the quick response and all the info when you say running from 5600-6100 rpm's i thought the max rpm on these motor is 5500.My max right now is at 5400 with that prop,i guess you mean it will reach those rpm's but you don't recommed it ?

[seacraft76]

also if i was to switch to Quicksilver oil would it matter if i switched all at once or should i slowly start mixing the quicksilver oil into my gas tank as i use up the omc oil" i premix my oil"

[Fr. Frank]

That 1983 "115" hp motor is capable of producing over 170 hp at between 8000-9000 rpms. The inline 150 version was capable of making nearly 240 hp at 9200 rpms. But you DO NOT want to run it between 6200 and 6900 rpms, unless you're rapidly accelerating through that range. Mercury ran some tests in the early 80's and found the I6 motors will self-destruct rapidly if run continuously in that range, with the most destructive range being 6400 - 6700. Something about destructive harmonics.

For normal use, you should consider 5500 as the maximum rpm at which to run continuously, i.e.; for more than 10 minutes at a time. A few minutes at 5800-6100 will not be a problem.

You should be able to reach the max normal operating rpm (5500) with your boat at maximum gross weight. So propping your boat should be done with full fuel, and max persons on board (or their equivalent weight). That also means you will be able of exceeding that rpm with anything less than a full load, which is appropriate.

You can make the oil switch all at once, if you want, by just using the Quicksilver oil the next time you add fuel, because you're pre-mixing. The Quicksilver synthetic blend oil will mix/blend with any 2 stroke oil already in the tank. But if you've already got some OMC oil left over, use it, don't throw it away, it's good oil. Just don't use the really cheap stuff they sell at the major discount stores.

[jwclbi]

Not to get away from the subject but like many others i use the quicksilver 2 stroke oil for my merc believing its a better product. But as i think about it, and discussed with friends who use the yamaha oil, who is making the oil? Mercury, Yamaha, or any outboard company are not oil companies, where do they get it. And is it made by penzoil? shell? Exxon? There are only a few oil companies in the world so its got to come from one of those right?

[Fr. Frank]

Quicksilver/Mercury oil used to be made by Texaco, so it's probably made by Chevron now, as they bought out Texaco's refineries. I have heard, with no authority whatsoever, that Yamalube sold in the USA is made by both Pennzoil AND Ashland oil.
I just use Quicksilver oil, as I know it's as good or better than any oil out there, and I want my motor to last.

[NoBones]

We talked about this a while back...
I have a friend that did a chemical break down
of most of the popular TCW oils.
His scientific results were that Mercury oils
have the highest and best properties of all
of the leading major brands.
I will look in my archives for these results if anyone
would like them....

This means if you have a Merc, Johnson, Suzi, Honda or Yami
etc, etc... that Merc oil would be the better choice.

See ya, Ken

[jwclbi]

No bones,
That would be great if you could find, I would love to show to my yamaha loving friends who badger me about my merc. They swear by the yamalube.....of coarse i have seen them swear at their yamaha's as well!!