whats the difference between a 1979 85 and 115

[SparkieBoat]

1979 85HP johnson, I just got my manual and was reading that the displacement on my 85 is the same as a 115 or 140 for that matter. so what is the difference in between the engines and how hard is it to make my 85 a 115 or 140??? I once heard that it was just the jets in the carb, but I did not believe that..but now seeing the displacement is the same maybe so.
Thanks for any help, I would like to get as many horses as possible.
Sparkie

 

[ezeke]

Re: whats the difference between a 1979 85 and 115

You would need to replace the carburetors.

The ports are larger on the higher rated engines.

You should upgrade to the larger exhaust covers.

 

[SparkieBoat]

Re: whats the difference between a 1979 85 and 115

can you tell me what year modle motors would have the interchangeable parts..also is as high as I can go 115 or can I turn it into a 140?? a 140 would be really cool.
Thanks Sparkie

 

[Faztbullet]

Re: whats the difference between a 1979 85 and 115

Exhaust port timing in block is different than 115, carbs are bigger on 115 adding exhaust cover and bigger carb will get you up to about 100hp.

 

[SparkieBoat]

Re: whats the difference between a 1979 85 and 115

thanks a lot Faz...I also have a 89' johnson 100..I am guessing that all I need to up it would be some bigger carbs??? so I would not have to mess with the exhaust cover??

 

[kenmyfam]

Re: whats the difference between a 1979 85 and 115

Difference between an 85 and a 115 is 30 HP
Personally if I wanted 115 HP I would get a 115 HP motor.
That is one reason I have a 140HP the only way up is a 6 cylinder !!!
Just my thoughts though.

 

[SparkieBoat]

Re: whats the difference between a 1979 85 and 115

Yes Ken, But I got this motor just cause it was on a boat I wanted..17.5' McKee craft CC.
I also have a 89' 100 Johnson that was painted up blue as an evinrude I guess that was to match the 115 rude cowl he had. and sold to me as a 115..this was before I knew how to read the numbers.
I have the 100 on a 28' pontoon boat that I will sell..and I put the 85 on an old tri hull I had laying around, just wanted to get it running at its prime, I will either keep it for my kids to use as a fish and ski boat or sell it.
I must say though since I have done all this work on it..it really runs good,,cranks good, even idles better than any older motor I have ever seen..I am kinda growing attached to the old motor. Its a 79'. I am starting to see now why so many people really like these OMC V-4s. I know where some more of these 85s are..the 115s are harder to find.

 

[kenmyfam]

Re: whats the difference between a 1979 85 and 115

Yes Ken, But I got this motor just cause it was on a boat I wanted..17.5' McKee craft CC.
I also have a 89' 100 Johnson that was painted up blue as an evinrude I guess that was to match the 115 rude cowl he had. and sold to me as a 115..this was before I knew how to read the numbers.
I have the 100 on a 28' pontoon boat that I will sell..and I put the 85 on an old tri hull I had laying around, just wanted to get it running at its prime, I will either keep it for my kids to use as a fish and ski boat or sell it.
I must say though since I have done all this work on it..it really runs good,,cranks good, even idles better than any older motor I have ever seen..I am kinda growing attached to the old motor. Its a 79'. I am starting to see now why so many people really like these OMC V-4s. I know where some more of these 85s are..the 115s are harder to find.

Was not trying to be smart there. Just stating that if I wanted 115hp or more I would go look for it rather than try to increase the power of what I have.

 

[Dhadley]

Re: whats the difference between a 1979 85 and 115

The 85 block can be made into a 115 or 140 (flywheel rated). As mentioned, the port timing is different as well as port area. Your 85 can be made into a 115 or 140 but you'll need to take the block apart to do the machine work on the ports. Changing the exhaust is pretty easy as long as you have the bubble back parts.

No matter what you do it'll never make the torque of a V4 looper.

 

[ezeke]

Re: whats the difference between a 1979 85 and 115

And, the 1989 100HP is approximately the same actual horsepower as a 1979 rated 115HP.

 

[Faztbullet]

Re: whats the difference between a 1979 85 and 115

As Dhadley said it can be done but this is not something a customer can do, it would have to go to a shop customizing in this type work. If you going to tear it down and have it ported ,it would be cheaper to find a 140 used block that already has correct exhaust mod's but you will still only get about 120hp at prop. If you want to go fast get a looper as a whole lot of mods can be done to them I have on my winter projects a 140 looper small bore to big bore conversion with fingerports,modifying a fasttrac midsection and swapping lower unit guts into a lighting gearcase to try on my Allison, I am scrapping the 3 cylinder 75 idea

 

[emdsapmgr]

Re: whats the difference between a 1979 85 and 115

The 135/140 engines all used unique high compression heads, so you'll need to look for a set. You can pickup maybe 10# compression. Make sure the head firing faces are not pitted from a prior engine failure. THe 135 heads don't have the coil support brackets cast into the side, but you can adapt something in order to use the heads.. High performace carbs have larger carb throats to flow more air and fuel. The front flange of the carb has the carb throat size cast into it. 1", 1 3/16", 1 5/16" etc. Likely you will need to rejet them if you don't add the exhaust bubble and change the porting. The 140's (and some early 115's) used the rubber intake filler blocks-322684. They are NLA, but worth installing-worth maybe 5 hp. When you have the intake off, consider adding a set of composite reeds. They are a nice addition-nice idling and midrange punch.

 

[Boblester40]

Re: whats the difference between a 1979 85 and 115

About 30hp Ho ho ho , sorry ill get my coat

 

[SparkieBoat]

Re: whats the difference between a 1979 85 and 115

wow thanks for all of the info guys..I did not know how much involved it could get. I just want to get the best power and performance out of the motor without doing a whole lot to it. I thought if it was just changing carbs it would be easy.
I actually just found a 80s model 115 for sale here locally for $100. I may just put the carbs and exhaust cover on my 85 for hopefully a 10-15 HP boost.
My main project is my Mckee Craft. I just brought a 96' 150 Intruder Looper.
My thoughts on the 120-140 is that the weight was the same as the 150-175 so I went ahead with the V-6. So this 85 is just really a side show for me.
It seems that some of you guys have some real knowledge and have done some serious modifications before. I am not ready to get that involved yet.
I am hoping to do my first engine rebuild next year..I am doing the gear case on my 150 now. So I am learning much.
And Ken, I didnt take your post wrong at all, I appreciate all of your help and advice. Thanks to all.
Sparkie

 

[emdsapmgr]

Re: whats the difference between a 1979 85 and 115

A good move. You won't believe the difference between a V4 and a V6. Huge difference. Those 150's also came in a high perf model. Look for the GL designation in the model #. It's probably around 165 prop hp.

 

[SparkieBoat]

Re: whats the difference between a 1979 85 and 115

the model tag is missing..is there another way to id the motor..I looked all over the power head for a model # with no luck so far.