Totally Confused on 2-Cycle 115hp motor

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Capt. Scully

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Firstly, never had a 2-cycle motor, always been a 4 cycle (just spoiled I guess). can't find a repair manual for this motor. There is a large (and I mean LARGE) opaque plastic tank towards the top and front of the engine. Secondly, is this the 2-cycle oil tank or mixing tank for the fuel and oil ? If that is the case, where do I put the 2-cycle oil, NO, it won't fit in there. LOL
I am an "old salt, but willing to learn new tricks".
 

Tim_C

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First, we need more info. What is the year, make and HP of the motor? 'Large' is relative, especially since you said you aren't familiar with these motors. Photos would help. For larger motors this would be the emergency oil reserve tank. As stated above most motors have an auto oil injection system. If the motor is pretty old the auto-inject may have been removed after it failed. Then the user would have to premix oil and gas and the oil reserve tank would no longer be needed.

Is this motor mounted on a boat or on a test stand? Most service manuals for the past 35 yrs are available on-line... some free and some pay. Type service manual and the above requested info in a search engine, the motor serial number will help narrow the search range even more.
 

Pat Dilling

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It would help to know the make and year of the motor. Also, is there an oil tank in the boat itself with a hose going to the motor?
 

Capt. Scully

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First, we need more info. What is the year, make and HP of the motor? 'Large' is relative, especially since you said you aren't familiar with these motors. Photos would help. For larger motors this would be the emergency oil reserve tank. As stated above most motors have an auto oil injection system. If the motor is pretty old the auto-inject may have been removed after it failed. Then the user would have to premix oil and gas and the oil reserve tank would no longer be needed.

Is this motor mounted on a boat or on a test stand? Most service manuals for the past 35 yrs are available on-line... some free and some pay. Type service manual and the above requested info in a search engine, the motor serial number will help narrow the search range even more.
Ok this is a 2005 Mercury 115hp. Cant find any other oil tanks in the boat. the tank was so large that it scared me, wasn't sure. Thanks for the come back and will try the on-line stuff....Capt. Scully
 

Tim_C

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No other tanks in the boat that I can find....its a 2005 Mercury 115 hp
Here is one source for manual and parts.

A youtube

I highly recommend you take the boat and motor to a marine mechanic and have him familiarize you with the motor.
 

Pat Dilling

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I highly recommend you take the boat and motor to a marine mechanic and have him familiarize you with the motor.

I absolutely agree with this. I used to think outboard motors, 2-strokes especially, worked by magic. They are sophisticated pieces of machinery and very dependable if operated and maintained correctly. Taking time to educate yourself through reliable sources could save you much money and grief in the future.
 

Duane Mauzy

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If it is like my last 115 Mercury it’s a oil tank, there should be a cap on the top of the cowling, under it will be a yellow cap with a dip stick. Fill the tank to the full line on the dip stick. If you overfill the tank it will leak out under the cowling.
 

Butch

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Is it an OPTIMAX 115? 3 Cylinder? This was the original engine on my Nitro 2005 188 Sport. Make Sure before you get a manual you know what engine it is. Fuel Injection or Carbureted makes a difference.
 

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