SWAPPING FROM 115 TO 85

[fireman_103]

I have a 1977 Evinrude 115 which number three lost compression and in scared up. I have a 1977 Evinrude 85 that has good compresson but needs carb and powre pack. Will carbs from 115 work with out changing Jets if not do I just have to change the Jest that are viewd from th side only. Also what size wrench do I need to take off fly wheel nut. 1 1/4 is to small I was told it looks like a 1 3/8.
thanks

 

[ezeke]

Re: SWAPPING FROM 115 TO 85

It is 1-5/16.

 

[tashasdaddy]

Re: SWAPPING FROM 115 TO 85

go to brp-evinrude, clik literature, then clik engine diagrams, follow prompt to your engines , and compare parts.

 

[ezeke]

Re: SWAPPING FROM 115 TO 85

You need someone like DHadley or Joe Reeves to tell you what to/can swap. They are different engines as to bore/stroke displacement, etc.

 

[WillyBWright]

Re: SWAPPING FROM 115 TO 85

I get in there through www.johnson.com.

Power pack-probably Yes.
Carbs, probably No. They probably have different throat sizes. Jetting would be purely experimental unless the porting, reed stops, and exhaust tuning are the same as the 115.

 

[jimmbo]

Re: SWAPPING FROM 115 TO 85

Carbs are bigger on the 115

 

[Chinewalker]

Re: SWAPPING FROM 115 TO 85

Flywheel nut is 1-5/16....

- Scott

 

[Dhadley]

Re: SWAPPING FROM 115 TO 85

The 115 carbs will bolt on but will probably flow a lot more fuel than is required by the 85. The bore of the 85 is 3 3/8" (3.375") and the 115 is 3 1/2" (3.500").

I've never made that swap so I'm guessing but I'd think the carbs would work, the holeshot might be slower, you might pick up a tad on top and your mileage would suffer. All of that can be overcome with jetting but unless you happen to have a bunch of carb jets it won't be easy.

That being said keep in mind that the carbs don't know what motor they're on, they just flow fuel according to how much air is flowing thru the venturi. The smaller bore and smaller ports might not create enough velocity to be very noticable. It's easy enough to try.

What's wrong with the 85 carbs? If they just need cleaning, it's easy enough to do that.

 

[fireman_103]

Re: SWAPPING FROM 115 TO 85

I have the 85 carbs and will rebuild them. Just trying to take a short cut. Now I have another problem. Number one is not firing. I have changed the coil and power pack and it is still not firing. It will fire the first time i turn it over then stops. The other three are firing but the engine will not start and dont even sound like it wants to. Compression is 95 in all four. Do I need to change stator base? How can I check this.

 

[tashasdaddy]

Re: SWAPPING FROM 115 TO 85

i'd try another compression guage, 95 is getting to the low side. how long has this engine been sitting.

 

[fireman_103]

Re: SWAPPING FROM 115 TO 85

Motor has been sitting for couple of years. I used the same gauge on a 70 johnson and got 125

 

[fireman_103]

Re: SWAPPING FROM 115 TO 85

I changed the stator base and it is now trying to start. With a 95 compression on all four will that get better with time or should i just not bother using the motor at all.

 

[seedpws]

Re: SWAPPING FROM 115 TO 85

You could try and decarb the motor with seafoam and it might get the compression up.

 

[ezeke]

Re: SWAPPING FROM 115 TO 85

ttt​