About to buy a 1989 Merc 115 6 cyl

[spgla]

I am about to buy a 89 Merc 115 inline 6 and looking for feedback on history, typical problems, specific glitches, etc. I'll be using it in salt, fresh and brackish water. I read somewhere that pre '92 Mercs didn't hold up to salt that well. One mechanic said all he knows about is some ignition problems being typical. Any experts or anybody using this motor I would really appreciate the feedback!<br /><br />Thanks

 

[dicktaber]

Re: About to buy a 1989 Merc 115 6 cyl

Last November I bought a 1972 17'er with a 1982 Merc 115. Had an old faded-away sticker on the back of the cowling; looks like it's original dealer was in Miami. Don't know how long it spent in the salt (I bought it from a guy who lived on the Mississippi in Illinois) but it's still looking good--just a little cleaning and repainting of the lower unit this spring. Runs great too--I asked on this board before I bought and heard nothing but good things about the inline six. Runs great, smooth, good power, sounds great and the throttle response is super. Now that I replaced my idle stabiliser it never dies at idle either...guess you could say I'm sold on it...

 

[spgla]

Re: About to buy a 1989 Merc 115 6 cyl

Thanks Knot2Much. I ran the boat this afternoon and it seemed to be in solid condition. I'm having a mechanic do a complete check tomorrow. The motor is on a Cobia 18' dual console and seems to run very smoothly at 4500 rpm at about 30 mph. I wonder what engine speed you cruise at? I appreciate the feedback.

 

[dicktaber]

Re: About to buy a 1989 Merc 115 6 cyl

That's just about right for me--4000-4500, about 30 mph...have only had it out a half-dozen or so times and have had other (non-motor) issues. Just put on a 15P prop (from a 17) and now it'll happily to rev to 5500, but I'm okay at 4500 for now. I really want to check the timing before running WFO for extended periods; I just read too many stories about blowing up motors, and I can't afford that!

 

[spgla]

Re: About to buy a 1989 Merc 115 6 cyl

Knot2much,<br />I had the motor checked at the shop and everything checked out. It had one problem with the #1 cylinder not firing sometimes and they said it was one of the powerpacks, so I need to have that replaced. We plan on buying the boat and I am wondering what grade of fuel to use and what oil and oil mixture to use. I have heard mixed reports on running 93 vs. 88 octane, but I have heard about 24:1 on the oil almost across the board. Some people said synthetic. What are you running and where did you get your info.<br /><br />Look forward to hearing from you and to running the "tower of power" as i've heard it refered to.<br /><br />thanks for the prop tip. Don't know if you've heard but I found a merc oriented site called screamandfly.com. May be of some use to you.<br /><br />spgla

 

[Jango]

Re: About to buy a 1989 Merc 115 6 cyl

GreaT Motor - Have a friend who has a 79, 17ft Procraft with a 115 Merc (1979. Boat is a Deep Vee, motor and Boat weigh 1800 lbs. <br /><br />WOT with a 21 Pitch Prop, turns 6000RPM @ 55 MPH+.<br /><br />I believe the 115 Merc performs more like a 140 or 150