1997 Merc 115hp question

[BBK1]

I have a 1997 Mercury ELPTO 115 HP on a 17ft deep V. We bought the boat 3 years ago from a guy that treated the rig like crap. We had some problems with the lower unit and some problems with the tilt+trim unit. The whole time we have had the motor it has seemed sluggish. We are only getting 43mph top end all trimmed out with 1/2 tank gas and when idling it seems to spudder and run ruff. We replace the plugs every other year but I was wondering if we should change the fuel filter or run some carb cleaner through it. (we run sea foam through it every winter) When we bought the boat from the dealer he said we should be getting 50-55mph out of it but we have yet to hit 44.
We run 89 regular no ethanol.


I should add that sometimes when backing it off the trailer, when I shift from neutral to reverse or reverse back to neutral it dies. Sometimes it will shift fine but when I put it in gear it dies. Almost like its not getting enough gas to shift it over.


Any suggestions?


Heres a pic.

 

[BBK1]

Re: 1997 Merc 115hp question

Edited, had wrong year.

 

[99wellcraft]

Re: 1997 Merc 115hp question

I have 99 115 elpto and my buddy has a 2002 115 and they both idle rough when they are cold and even sometimes when they are warmed up too. That motor has something they call, like a 2 + 2 feature as it was explained to me. it runs on 2 cylinders when it is below 2000 rpms, but when it gets above that it kicks in the other 2 cylinders and smooths right out. Mine is on a 1998 19' Wellcraft deep V and it runs about 38 mph in saltwater with 2 people in it and a half tank of fuel. Doesn't sound like there is any problem to me. the stalling thing is a pain but every 115 around that year that I have ever been around does exactly the same thing. My brother has a 2007 115 opti max and it doesn't do this. I think they fixed it later on in years. I am not a mechanic just sharing my experience.

 

[BBK1]

Re: 1997 Merc 115hp question

Thanks, thats good to hear.