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Just bought a 2001 13' Sport with Mercury 40 HP. It's a 2 stroke and the dealer told me I needed to use 50:1 fuel mixture. I'm thinking that's wrong. After taking her out twice, and investigating the low oil alarm I heard upon taking sharp turns, it looks like the motor is actually oil injection. This is blowing my mind. I didn't know that was a thing that existed. So I'm thinking I merely need to fill up the oil reservoir each trip, on the motor, and start using straight gas.

Can someone confirm that I got this right?

note: My motor does not say "fuel injection" on the side like some pics I see online. But it does have an oil reservoir that says it takes TC-W 111.

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Maybe the dealer didn't tell you the whole story.

In my experience, oil injection systems are problematic. Every one i ever owned ended up failing. I personally would never use one.

Keep the tank empty and use premix. If you use straight gas and the oil system fails, you have 1 dead motor.

Maybe the dealer already knew it was broken...

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So you got a new to you Whaler!! Outstanding choice. You should have gotten an operators manual for the engine in the packet with the boat. That booklet,operators manual would tell you in detail what to do for your engine. If you don't have it, go by a Mercury dealer with the Model number and serial number of your engine and get the true scoop from them, see if he would copy one for you. Your assessment of the oil is probly correct. Try Google the motor, everything is on the web these days.

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I would ignore the advice given in the 2nd post to this discussion. If that is accurate, Evinrude/E-tec would be out of business, since they ONLY make 2 stroke, oil injected outboards!

If your Merc 40 has an oil injection system, and it is NOT in need of repair, it should be used. Fill the on-board oil reservoir as needed, and use straight gas. If the oil injection system on this engine is not working, you made a bad deal on the boat, or it was mis-represented to you.

I have logged thousands of hours on Mercury oil injected engines, 90-200 HP, and they all have been flawless and work perfectly, with never a repair even needed.

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Our boat has a 1992 Yamaha 150 with "precesion blend". Oil is not mixed in the gas tank. Instead it gets added to a remote oil tank and injected as needed. Knock on wood, 26 years and counting.

"Fuel injection" refers to how the fuel is delivered to the cylinders. An outboard engine with "oil injection" could be fuel injected or carbureted. Many early oil injection engines were carbureted like my Yamaha. I suspect your Merc is too.

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Thanks, Finnegan, that's what I was hoping to hear. Your statement about reliability is congruent with what I am reading elsewhere.

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JRP, my bad, I meant to say, "oil injection". I've seen lots of images of Mercury 40HP 2 strokes that literally say "oil injection" on the outside of the motor. Mine doesn't. I think it's probably just a branding change Mercury has done over the years. 2001 models must not have said branding on the motor.

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My 2002 40HP Merc that came with my 130 Sport had oil injection. Worked perfectly. I suspect your engine might be the same model/design.
My suggestion is to fill the oil reservoir on the engine with high quality 2 stroke oil, such as Quicksilver premium plus, and mark the level at rest. Continue to use the 50:1 gas in the 6 gal tank- just in case the oil injection isn't working- and run through 1/2 tank or so. Check the level in the oil tank and if it's down from the "full" mark, you know the injection system is working. 3 gal of gas should consume enough injected oil so that you can notice the change. If the level dropped- you know the oil injection works and you can use straight gas. The double oil should be OK- might foul the plugs a bit but that's easily dealt with.

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My point exactly. That's what i was trying to convey in my second post.

If you fill the oil tank and its not working, the motor will be toast. If you leave the oil tank empty and do premix you'll be fine.

Maybe the CORRECT response would have been to speak to the dealer and ask him what he meant by his statement. Maybe it was just his way of beating around the bush rather than tell you he sold you a pig in a poke.

Regardless of other's experience with oil injection, mine has been dismal. That's why I don't own a system like that anymore.