115 Mercury power loss

[jimmydod]

115 Mercury outboard serial #394-2559 is having power loss trouble. Ran great for 8 minute run across lake at full speed and the next run out it would only idle at 5 mph. While idling 5mph on full throttle, will start to speed up and then down on it's own. Checked vent and it's good. Runs great in the driveway everytime. Can you help me out?<br /> jrchappe1@yahoo.com

 

[FishermanRich]

Re: 115 Mercury power loss

What else can you say about how it is acting?

 

[Skinsk]

Re: 115 Mercury power loss

Have you guys checked for water in your fuel?

 

[FishermanRich]

Re: 115 Mercury power loss

Sea Foam - from what I read - should be able to get the water to be in suspension and burn up better.

 

[Skinsk]

Re: 115 Mercury power loss

Water is hard to see going through a fuel line. What I'd do is get a fuel line quick connect (the male side, like the one on your motor), and a clean bucket. If the boat is on a trailer, crank the bow up, and then plug the male connector into your fuel line, and prime a few gallons into the bucket. Look to see if the fuel separates out like salad dressing. Water on bottom, fuel on top. With pre-mix it should be easy to see, but with strait fresh fuel it may take some close looking to see if there is separation. <br /><br />If you find no water, just get a funnel and dump the fuel back into your tank.. <br /><br />I think most boats should be equipped with a water sep fuel filter installed in the boat anyhow. It adds another layer of filtration, and will catch some water that get inside fuel tanks. Such as from condensation, or cheap gas, or from water coming in through poor gas cap seals or vents.. <br /><br />Scott..

 

[Skinsk]

Re: 115 Mercury power loss

Also, just cause I can't figure it out, are these 115's the 4 cylinder 2+2 motors?

 

[FishermanRich]

Re: 115 Mercury power loss

I did a search and here is what I found:<br />Water in Gas, Junk in tank collecting on fuel pickup screen in the tank, Cracked fuel hoses or connections allowing air into fuel line, Backwards facing primer bulb (not likely), Fuel Tank Vent clogged or closed, Fuel Pump clogged or diaphragm broken - not pumping enough gas - need to pressure test, bad spark plugs, bad wiring, bad stator - frayed wiring under the flywheel, bad CDI or switch box, bad stabilizer module, bad coil, Sticking float(s), clogged carbs - requiring rebuild/cleaning - Check main jets & imulsion tube - reset/check float levels, out of sync carbs, out of timing, crank case vent hose clogged, compression may be bad.

 

[FishermanRich]

Re: 115 Mercury power loss

Jimmy, did you ever find / fix the problem?

 

[loiue13]

Re: 115 Mercury power loss

I have the same motor with same problem<br />going over the list that was posted i think i got the same list <br />I've changed floats,plugs,wires,stator fuel lines,checked vent,checked primer ball,checked throtle cables, still same ol thing runs fine with no load witha a load maxes about 10mph<br />but i had a question also is the lower unit pressurized cuz mine has a leak and wondered if this could effect my power loss under load??

 

[mikemondo]

Re: 115 Mercury power loss

Hey guys<br /> Ya know , mine acted like that too. After going over everything I could think of, one night in my driveway I took the cover off and ran the motor in the dark. It looked like Bagdad a few months back. Sparks were arcing all over. I thought I had good wires but I didn't. So I replaced them very carefully and also I tightened the fitting a little where the fuel line actually first enters the motor. Now it runs like it is supposed to. Good luck Doo

 

[Max7]

Re: 115 Mercury power loss

I was having same problem I change power packs and spark plugs cables and problem end