1994 Yamaha 115 2 stroke questions (water separator filter? ring-free? )

Clinton37

Cadet
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Dec 28, 2016
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10
I currently own (for about 3 months now) a 94 Ebbtide 178SS with a 94 Yamaha 115 2 stroke. The boat has a 24 gallon internal fuel tank and I premix at 50:1 w/ non-ethanol gas. Freshwater use only in SC mostly pleasure riding, fishing and pulling daughter on tube. It seems to run just fine. There are no filters on the fuel line, however, either before or after the tank. Question 1...Is a water separating filter absolutely necessary..especially since I premix the fuel? Also, do you recommend using the Yamalube Ring-Free additive? Any other recommendations? Thank you!
 

dingbat

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Nov 20, 2001
Messages
15,481
Question 1...Is a water separating filter absolutely necessary..especially since I premix the fuel? Also, do you recommend using the Yamalube Ring-Free additive? Any other recommendations? Thank you!
Not sure what premixing your fuel has to do with filtering contaminants and moisture from your fuel.

Oil and water don't mix....any water in the fuel will displace the oil so badly needed by a two stroke. If you have water in your fuel, Contrary to belief, you have a higher probably of water contamination using non-ethanol fuel than E10. Ethanol actually help keep your fuel "dry" by absorbing any free moisture that has accumulated in the fuel tank.

Carbon buildup is a problem in 2 strokes that needs attention. Running good fuel and high quality oil goes a long ways toward keeping carbon build up in check. If nothing else, run Ring Free in every couple of tanks for good luck.
 

robert graham

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Apr 16, 2009
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The Walmart/Atwood fuel water seperater costs $28....easy to install on transom and great preventive maintenance....I've always used Ringfree on my 1999 C90 2 stroke pre-mix motor....never a problem.
 

QBhoy

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Mar 10, 2016
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8,308
Hi
firstly. Congratulations on having such a great engine.
Secondly, I’m normally all for pre mix and doing away with the oil injection...but if ever there was an engine with a reliable oil injection system...it’s this one. What happened to it on yours ?
 

Clinton37

Cadet
Joined
Dec 28, 2016
Messages
10
Thank you Dingbat, Robert Graham and QBhoy! Great information and advice. Dingbat, I mentioned the pre-mix because I was under the impression that the water separator filter was designed for just gas. I thought maybe the gas/oil pre-mix might cause some problems with the filtering mechanism? Thanks for clarifying that. QBhoy, the oil injection was removed before I bought the boat and the previous owner told me this was done just after the warranty ran out because he just didnt trust it.
 

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dingbat

Supreme Mariner
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Nov 20, 2001
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15,481
Dingbat, I mentioned the pre-mix because I was under the impression that the water separator filter was designed for just gas. I thought maybe the gas/oil pre-mix might cause some problems with the filtering mechanism?
Oil molecules are a lot smaller than the recommended 10 micron filter. ;)
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Hi
firstly. Congratulations on having such a great engine.
Secondly, I’m normally all for pre mix and doing away with the oil injection...but if ever there was an engine with a reliable oil injection system...it’s this one. What happened to it on yours ?

The C90 model designates a commercial rated motor or base model without all available features including oil injection...I far prefer the premix motor for it's simplicity....but lots of folks prefer oil injection for it's convenience.....
 
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