Oil mix
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- This topic has 30 replies, 14 voices, and was last updated 2 years, 5 months ago by reivertom.
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October 15, 2021 at 8:02 pm #248137
The section of a bearing that is under pressure
as a motor runs has the thinnest film of oil.
There is only room for so much oil there no
matter how much you mix in to fuel. Once you
have enough to prevent contact, there is no
benefit to adding more. Then there is friction.
The slicker the oil the less wear. You see it’s
the friction of the oil as the components rotate
that wears away the metal. Just as water does
running over a stone. It’s the same for the rings.
For me it’s the quality that will reduce wear
resulting in longer engine life. Others obviously
see it differently.October 15, 2021 at 8:41 pm #248138…feed that journal with premix…50/1 verses 16/1 on a plain bearing….not my motor…roller elements 50/1 is fine. With a high silicon piston skirt 50/1 is okay when things are perfect. Early pistons were soft and need 16/1.
I understand the gas flashes off leaving the oil film. 50/1 is not enough oil for a non-pressure fed plain bearing. 50/1 was a boardroom decision for sales. The newer crowd sees an oil cloud they assume the motor is worn out like a 4 stroke.
The very first week of getting my 4 year in mechanical the prof says any product that lasts too long is a product failure…and products are designed to make investors money but that’s another issue..
- This reply was modified 2 years, 5 months ago by rudderless.
- This reply was modified 2 years, 5 months ago by rudderless.
- This reply was modified 2 years, 5 months ago by rudderless.
- This reply was modified 2 years, 5 months ago by rudderless.
- This reply was modified 2 years, 5 months ago by rudderless.
October 16, 2021 at 1:24 am #248144When OMC switiched to 50 to 1 all the motors had fixed high speed jet which prevented operators from running them too lean.
October 16, 2021 at 2:17 pm #248162…and keeps operators from running slightly rich for safety. Every fixed jetted carb motor I have received I go one hotter plug and jet to that. The folx on the chainsaw forums understand this. Manufactures have no incentive to make their products live much past warranty period. By running short on oil and slightly lean this is accomplished.
The only 4 stroke outboard I have owned from new was jetted too lean for optimum operation also. Most carbed 4 strokes of today are jetted slightly lean …especially the low speed jet.
- This reply was modified 2 years, 5 months ago by rudderless.
October 18, 2021 at 8:20 am #248255I stand by my opinion expressed before, this OMC recommendation is dangerous when it comes to CD/AD series engines with plain bearings. 16:1 is what should still be used. The beauty part of these engines is that they smoke very little, even at 16:1 when in good shape and properly tuned…
October 18, 2021 at 12:39 pm #248267Here’s a ’58 Johnson CD which I just finished servicing. It’s running on a 16:1 mix using Canadian Tire dino oil and shows no smoke at idle and just a bit when revved up some.. This wouldn’t even be noticeable if it was on a boat out on a lake.
October 18, 2021 at 4:08 pm #248281Here’s a ’58 Johnson CD which I just finished servicing. It’s running on a 16:1 mix using Canadian Tire dino oil and shows no smoke at idle and just a bit when revved up some.. This wouldn’t even be noticeable if it was on a boat out on a lake.
What a beautiful engine, thanks for the testament to the old engines….
October 18, 2021 at 7:22 pm #248297Anyone remember the 100/1 recommended mix some years ago? how’d that go…
October 19, 2021 at 3:34 am #248336I remember seeing a can back about 1963……..can’t remember the brand. It was in a small sealed can, similar to a baked bean can, but smaller. I think it came from Singapore and if I remember correctly, it had a warning on it that it wasn’t good for your health and to be careful using it.
It was a bit of an eye opener to us young guys who were used to using 24 to one oil ratios
Monte NZ
October 19, 2021 at 7:42 am #248339Anyone remember the 100/1 recommended mix some years ago? how’d that go…
Great point indeed…. This is what happens when the marketing department has way too much control….
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