In-Line 115 HP After 1982 is High Output?

[SeaKaye12]

Hi,

I have read on another forum that there is a change in the 115 HP mercs after 1982. That they are actually 140 HP motors.

I would like to be directed to more information on this. What exactly is different?

Specifically...I have read that all 115 motors after the following serial numbers are "High Output":

U.S. Serial No. - 5829464 and above
Australian Serial No.- 8071 135 and above
Canadian Serial No. -7171253 and above

Also; does the 2+2 design factor into this at all? When did 2+2 versions start and stop?

I guess what I'm really looking to find is a source for information on the evolution of the inlines after 1982 or so....

Thanks, Chuck

 

[79Merc80]

Re: In-Line 115 HP After 1982 is High Output?

1982/83 is about the time when Mercury changed from Crankshaft rating to Propshaft rating. Basically, what Mercury did was take the old 140 and make it the new 115 and take the old 115 and make it the new 90 and dropped the old 90.

In 1986 the inline 6 90hp was changed to an inline 3.

In 1989 the inline 6 115hp was changed to an inline 4 (2+2), also the 100 and 125 was the same design. This held until Mercury dropped the 2-stroke (Except the Optimax) line for the 4-strokes.

Once the industry went to the propshaft hp rating system, it has stayed that way, so an 85 115 is about the same as a 2000 115.

Hope this answers your questions, if not some of the more knowledgeable people on the board will chime in shortly.

Craig

 

[emckelvy]

Re: In-Line 115 HP After 1982 is High Output?

Hi, Chuck, I've been in a small Sidewinder powered by a 'prop rated' 115 and believe me, that motor was a Beast!! Incredible mid-range surge and it didn't slow down at the top end either!

It sure put my old '71 1350 to shame, and that motor was a real strong runner in its day.

The late-80's Inlines are definitely the Best of the Best and benefit from a lot of design improvements, including the primer system instead of choke shutters; upgraded 'swept-back' lower units ('79 and up) which are also more 'hydrodynamically' designed to resist blowout at higher speeds; and something you wouldn't notice unless you tore one apart, special corrosion-resistant coatings on the exhaust manifold baffle & cover (and on the inner water passages of the block if I recall), that really make a diff in the durability of the motor in salty and brackish water.

And did I mention the integrated Power Tilt 'n Trim! Another big step forward. Just think what another decade of refinement would have brought. Instead we got the 'infamous' 2+2 design!

Have a Good One...........ed

 

[buzzm19]

Re: In-Line 115 HP After 1982 is High Output?

You guys know a lot about these motors, I had a 1350 and it was a strong runner and now have a 1978 115hp and does run strong to, of course if its bolted to a 14' glastron (james bond). I was wondering if the newer l6's would be heaver and would they match up to the older throttle cables? Thanks Buz

 

[79Merc80]

Re: In-Line 115 HP After 1982 is High Output?

buzzm19:

From 1968 - 1988, the inline 6 used the same 99 cid block, so the weight of each is within 10-15 lbs of eachother. I think the most weight difference was in 1984 when the integrated power trim and tilt was added to the newer style transom bracket.

The throttle and shift cables should be a complete match, but in 1980 the electrical connection was taken from the external on the side of the cowling to an internal behind the front cowling support bracket, also a different style plug on each end.

Hope this answers your questions.

Craig

P.S. My parents had the 69 1250 and it was a dream to run and I now have a 1984 Mariner 90 (Older 115) and it runs fantastic. Idles down to a crawl (1.9 MPH) in gear

 

[buzzm19]

Re: In-Line 115 HP After 1982 is High Output?

Thanks guys, this forum has been such a help I don't know how I would of done with out it, probably a lot of aggg. Thanks Buz

 

[SeaKaye12]

Re: In-Line 115 HP After 1982 is High Output?

We're getting there guys I'm gleaning the bits and pieces from each of you and making my own "timeline" of sorts.....

I also stumbled across the thread that Clams started on Scream and Fly back in 2002. They're still posting to it There's so much to know about just this one engine line

http://www.screamandfly.com/showthr...the-Inline-Six.&highlight=history+merc+inline

I just had the opportunity last weekend to see two engines side by side with their cowling removed: a 1978 150 HP and a 1979 140. That was the year that they changed from the distributor to ADI. What a difference under the cowl! The old '78 was so open and airy in there...the big ol' distributor was there.....but none of the extra wiring and electronics that made up the ADI system. The '79 looked really "packed in" by comparison.

Well; now to continue my search to determine what made the various horsepower differences in that same 99ci block. Learning is such fun! Thanks all....feel free to keep adding to this thread.

Chuck

 

[buzzm19]

Re: In-Line 115 HP After 1982 is High Output?

Chuck, I don't know if you read the thread just posted with the topic (new to mercury's 1970 115hp) he shows pics of his dist and looks like it was converted to points(check spark box connections) If so I would love to do mine, any info would be great as I am having nightmares with my 1978 115hp. Thanks Buz

 

[SeaKaye12]

Re: In-Line 115 HP After 1982 is High Output?

Thanks Buzz....I went and looked. Interesting...

I've never heard of anyone doing that; I have no idea just how unusual his conversion really is. He seems intent on changing it back; I wonder why if it runs OK that way...

Chuck

 

[INDYCAVER1]

Re: In-Line 115 HP After 1982 is High Output?

I really dont know if I want to change it back yet. It seemed to run good when the guy started it to sell it to me, but I havent tried to mess with it yet since I have had it. I just built my engine stand this weekend and plan on tinkerin with it within the next week or so. Im am only worried that the timing wont advance right with the new setup. Its never been in the water, and I dont know when I would get a chance to put it on my boat. I just took my boat out today with my old Johnson and It ran great today for the first time in a long time, and It will be hard for me to swap it out with my new motor till i know it will run good and strong. I wish there was someone local that could come look at this thing and tell me what they think about it. If it does seem like it would work great I would love to share the secrets of the swap, but right now I am scared I will screw it up if I go and mess with it. buying it used off craigslist doesnt help me findin out who originally did the swap.