Oil/gas mixture for an 85 yamaha 40hp 2cycle

[Dalorean]

This is a new motor to me in terms of owning and understanding. I know it sat for a year with the previous owner so I cleaned out the gas tank and am ready to put new fuel. Online I've seen to use 50:1, 80:1, and 100:1 all on these yamahas. I'm lost here and want what's best for this older motor. Also what brand of oil is best and what gas? Non ethanol? Ethanol? Any carb cleaner additives recommended or keep that stuff out altogether? Also I'm new to 2 cycle engines altogether, I barely understand my retarded chainsaw thank y'all!!

 

[robert graham]

50:1 is recommended....I use ethanol gas with no problems. I use Yamaha Ringfree all the time and Stabil for long lay-up periods. A Walmart/Atwood fuel/water seperater($28) is a great addition to your transom...if you don't already have one...

 

[boscoe99]

Yamaha says 100:1

 

[Dalorean]

Hmm... What about changing the ratio every time I fill the tank up? 50 the first tank then 100 the next and so forth?? Since I'm gathering theres different opinions here? Thanks guys y'all kick serious assness

 

[robert graham]

My understanding was that Yamaha tried 100:1 for a year or so and found that while running it lubricated O.K., but when motor was laid up for a length of time that the 100:1 didn't provide enough oil to protect internal shiny parts like bearings, journals, cylinder walls,etc.....then they returned to 50:1 in most motors....Any thoughts on this Boscoe?

 

[Dalorean]

So I mixed the 50:1. And it is not oily at all. The gas I cleaned out that was in it when I got it was basically motor oil. Really thick. I noticed theres the oil emblem on the cap. Why? Isnt that where the gas mixture goes? My chainsaws have the gas emblem where the feul goes. This is throwing me off. I dont want to blow the motor from lack of knowledge. That is where the 50:1 mixture goes in right? And theres no crank case oil on these motors? Just wondering if it was supposed to be real oily mixture? Thanks.

 

[robert graham]

A gas/oil mixture can lay in a tank or container and under certain conditions the gas can evaporate off and leave behind mostly oil.....

 

[robert graham]

Sounds like you need a manual or at least some one on one instruction on the operation of this motor.....there are things that you need to know or mistakes can get expensive$$$$$

 

[GA_Boater]

Lets see a naked photo of your motor - No cowling. I want to see this cap with the Oil symbol and what the cap screws onto.

You cleaned out the oil tank, that's why the "gas" was thick. If you put pre-mix fuel in the oil tank, DO NOT START THE MOTOR. You gonna blow the motor up.

 

[Dalorean]

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[Dalorean]

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[Dalorean]

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[Dalorean]

Sorry the pictures are inverted my regular camera is blurry so had to use the selfie camera. I looked up the serial number of the motor and it brought up saying its a 2 cycle and thats what I was told when I bought it.

 

[GA_Boater]

The pics aren't upside down. And you can add more than one pic to a post.

What's a selfie camera? You mean your phone. :doh:

Anyway - That is the oil tank and all you put in it is TCW3 marine two stroke oil. No gas!

Straight gas is put in your gas tank - The red or silver thing connected to the the black hose with a turkey baster bulb in the middle. It will say gasoline on it with safety warnings.

Search for an owner's manual online. You can find them for free.

 

[Dalorean]

Ok I got that tcw3 oil. That goes in that reservoir, and regular straight gas into the gas tank..no mix? What about the 50:1 ratio? I know I sound stupid and thats fine I never messed with a boat motor before. And I really appreciate all the help I'm getting here. I'll look for the manual online.

 

[boscoe99]

My understanding was that Yamaha tried 100:1 for a year or so and found that while running it lubricated O.K., but when motor was laid up for a length of time that the 100:1 didn't provide enough oil to protect internal shiny parts like bearings, journals, cylinder walls,etc.....then they returned to 50:1 in most motors....Any thoughts on this Boscoe?

Nope. Yamaha never changed the oil ratio. 100:1 on many models.

Most oil injected models idle at or around 200:1. So if a guy idles before he stops and then does not use his motor for a while he is going to be having even less oil to protect the shiney parts than a pre-mixed model using 100:1.

 

[boscoe99]

I remember when the oil mix was 25:1. When it shifted to 50:1 many folks resisted going to that ratio. Just knew they had to use 25:1 for adequate protection. Now with some models being at 100:1 the thought process is the same.

If just right is good, then too much has to be better. lol

 

[Dalorean]

I have not found any owners manuals online for free, all the ones I found charge. Does anyone have a link?

 

[GA_Boater]

I have not found any owners manuals online for free, all the ones I found charge. Does anyone have a link?

Then buy one! It's cheap compared to repairing a damaged motor by doing something wrong like filling the oil tank with pre-mixed fuel.

Forget about oil/gas ratios. The oil injection system does that for you and seems to be reliable.

 

[boscoe99]

Ok I got that tcw3 oil. That goes in that reservoir, and regular straight gas into the gas tank..no mix? What about the 50:1 ratio? I know I sound stupid and thats fine I never messed with a boat motor before. And I really appreciate all the help I'm getting here. I'll look for the manual online.

Why the ? mark after the words "no mix"?

First thing that you need to do is to find the specific model identity for your motor. Some use premix (100:1) where you mix oil with the gasoline at a ratio of 1 part oil to 100 parts of gasoline and then some use oil injection. The latter being where all you do is to add oil to the tank. You do not, repeat do not, add any oil to the gasoline. The system does it all for you automatically.

With the specific model identity known you can then find the specific owner's manual or service manual for your specific model motor.