1987 Mercury 115 Idling Issue?

[ShawnyBoy187]

Hi all, new to these forums. I got a 1987 Mercury 115 inline 6 cylinder and I got a question about it. At idle the motor has a shake to it out of the water. I would think that a little bit of shake is ok but this seems like more than average. When the boat is in the water and put into gear at idle the shake does seem to be worse. Enough to where I can feel it through the steering wheel, has even died while throwing it into and out of gear. Top end is smooth. No pinging or other sounds coming from motor while running. Compression is even across all cylinders. I am mechanically enclined but am new to outboard motors. I am wondering what to start replacing. I did bump the idle up from about 650 to 800 hoping that would solve the stalling when going into gear issue. Should i begin with new plugs? Carb rebuild? Any info about this would be awesome. Thanx alot.

 

[donzi gt230]

Re: 1987 Mercury 115 Idling Issue?

Assuming all 6 are firing, I would start with a linkage synchronization and general tune-up. The linkage synchronization needs to be precise, follow the manual step by step. If you're like me it looked a little daunting at first, but once you break it down to a step by step procedure it's not all that bad. On the first go 'round you may want to do it twice over to make sure everything is exact. My motors seemed to run fine when I got them, then I did the synch, and it was an incredible change. It may need a carburetor cleaning, but I'd start at the maintenance stuff. Turning up the idle may damage your gears from hard engagement so that's not a good way to overcome the stalling. If you don't have a manual yet, get only a genuine Mercury, I had to learn the hard way. You may be able to find the synch procedures on-line to get you started.

 

[Mi duckdown]

Re: 1987 Mercury 115 Idling Issue?

Shawny. If I where you. Being mech enclined. I would purchase an OEM MERC Service/ repair manual for that motor. The best investment YOU will every make.
It will answer all of your questions.
If Not. we are here.

 

[aussieflash]

Re: 1987 Mercury 115 Idling Issue?

First check all cylinder are firing and have spark.Then get back to us.Mine is an 88 V6 so my manual is no good to you.Definitely get a merc manual if you don't have one.The guys hear will help you find it.

 

[ShawnyBoy187]

Re: 1987 Mercury 115 Idling Issue?

Has anyone used the seloc manuals? Are they gonna any good? Found one on their site for $37...

 

[1979checkmate]

Re: 1987 Mercury 115 Idling Issue?

I have a seloc, they tell you enough to get you in trouble. There are online copies of the Merc OEM manuals which are a lot better.