Modern 2 cycle oil same as older???

[Tinker]

My question is: My motors call for 24 to 1 oil mix. That seems like a lot of oil. My motors are both 50's models. With the modern oils I notice the newer motors call for 50 to 1. Is this because the new oils are better or are the motors designed better. Could I lessen the oil used in my motors. They both leave quite an oil slick. Also can anyone tell me where parts are available for a 56 Neptune 1.7<br />Thanks<br />Tinker

 

[JB]

Re: Modern 2 cycle oil same as older???

Hi, Tinker.<br /><br />I believe that the leaner mix is because of engine improvements.<br /><br />Some guys here say they use 32:1 or 50:1 in their older engines and have no problems.<br /><br />How you use your engines may make a difference. Many oil injector systems use 100:1 or even 150:1 at idle and go to 50:1 only at WOT. In between the mix is in between.<br /><br />That suggests to me that the factory recommended mix is for safe operation in worst case use with worst case oil. <br /><br />I wont recommend that you use a leaner mix. You need to use your own judgement on that.<br /><br />Good luck.

 

[rterrian]

Re: Modern 2 cycle oil same as older???

For what it's worth, I have a 1953 5 1/2 Johson I have had since the early 70's and I have always used ashless oil at 50:1 even though they call for 24:1. In those days (the 50's) all that was availibol was outboard oil that was about the same as automotive oil.

 

[Chinewalker]

Re: Modern 2 cycle oil same as older???

Most 1950s motors REQUIRE the extra oil not only as a lubricant, but as a sealant. They have bronze babbit bearings and no rubber seals between crankcase chambers and on upper and lower crank mains. The oil helps seal them and also acts as a cushioning agent. 32:1 is the absolute leanest I would ever run ANY smaller 1950s Johnrude at, as they are primarily bronze bearings on all the moving parts. That's when using premium oil, too. I've got a pile of 1950s 3, 5.5, 7.5, and 10hp blocks that all show evidence of the bronze bearings being scorched and in some cases the blocks are holed where the rods came out. I've also got a bunch of 10hp and 15hp rods with ovaled wrist-pin ends - came out of motors with trmendous rod knocking noises - also due to too lean of an oil mix...<br />- Scott

 

[FlyBoyMark]

Re: Modern 2 cycle oil same as older???

Rite chinewalker...unless the engine is all roller bearing...better look out! 24:1 using TCW-III is MUCH better than using old standard 30 wt oil in these engines though. The only possible exception could be some of the VERY old outboards(40's and earlier...) need to be run on straight 30 wt mineral oil.

 

[alcan]

Re: Modern 2 cycle oil same as older???

I agree with Chinewalker, The older motors need more oil for sealing purposes. Now days we are all more sensitive about water quality. One half a drip of oil or fuel on the water will make a beautiful rainbow. We have also become more sensitive to smoke from our motors. The feeling that it is bad, and with most modern engines it is. If these older outboards are tuned and adjusted properly it should keep the emitions to a somewhat tolerable level.

 

[Yepblaze]

Re: Modern 2 cycle oil same as older???

I got a bunch of old crap I run daily. The 58 Johnson gets 24:1 and the 53 Merc 32:1 ( it has the needle bearings )I use Pennzoil Premium Synthetic Blend<br /><br />When in tune they really don't exhibit a lot of smoke. Unkess you are trolling one downwind with the right breeze.<br /><br />

 

[Tinker]

Re: Modern 2 cycle oil same as older???

Hey guys, thanks for all the info. Guess I"ll just fiddle with the mix a little and tune till I'm happy. They take a dim view of oil slicks on the lakes here in Montana. <br />Thanks again<br />Tinker