How much difference 85 vs. 115

[barbwire44]

Curiosity is killing me but I am currently running a 1973 evinrude 85 on my 17' sunbird, I recently purchased a 1981 evinrude 115 with tilt & trim. How much of a difference in performance am I going to see???? it's 30 hp difference and the tilt and trim will be a new addition, had people tell me a few miles an hour and others said night and day difference????
what do you guys think???

 

[jimmbo]

Re: How much difference 85 vs. 115

About 4 or 5 mph, maybe a couple more allowing for the power trim

 

[darrklim2]

Re: How much difference 85 vs. 115

Depending on the boat, but I think you should see a decent improvement in all around performance.

 

[barbwire44]

Re: How much difference 85 vs. 115

4 or 5 huh?? darn I was hopin for about 10 mph increase, but if I get 4 or 5 and a faster holeshot I will be happy. Fot that small of difference I might just wait until winter to install it after the paintjob. Do you guys think the tilt and trim will swap between the two motors?????? the mounts look very close, I haven't measured anything but thought that would be a quick switch, the cables in the control box look the same, just adding the little black box controller for the till unit, and swap controls out if the motor mounts would swap????

 

[iwombat]

Re: How much difference 85 vs. 115

Totally different T&T mechanism.

 

[barbwire44]

Re: How much difference 85 vs. 115

Thanks Iwombat...not what I wanted to hear but hey that's life, if I get over anxious I may tackle the motor swap on a rainy day.

 

[Dhadley]

Re: How much difference 85 vs. 115

You'll get better performance but not 10 mph. You'll have a better gearcase design. Between that and the TNT you should be able to mount the motor higher and use better design prop. That's where your increase will come in. All the controls are a direct swap / hook up, no problem. Add the TNT stuff and a switch at the dash and go have fun.

You can put the TNT & swivel brackets on the 73 but it's not going to be easy. There'll be a lot of fabricating involved including making something for the trim rams to push aginst. And you'll still have the old gearcase. You'll be far better off to use the 115 as is.

 

[jimmbo]

Re: How much difference 85 vs. 115

My est of 4 or 5 mph was based on experience with that swap but both engines had power trim. Adding power trim will change the difference, bepending on how your old motor was set.

 

[barbwire44]

Re: How much difference 85 vs. 115

I would swap them out right away but the 115 needs a water pump it just drips with the muffs on, And the ole 85 has been running really good lately, did put a new powerpack on it last weekend, but it was the original and an easy fix. As far as the motor height the old 85 is 3 holes out from the transom, I would have like it in further for the holeshot but the little lever that releases the motor to raise it for trailering broke off years ago and I have to have enough room to slide a screwdriver in and release the two little catch arms...LOL!!! A real pain in the butt somedays but, a gotta do what you gotta do I guess. You guys said something about mounting the new engine higher???? could you please explain this reasoning and how high would I mount it, my 85 I sat it so the fin was the level with the bottom of the boat.????