evinrude powerhead swap 85 to 115 or 135

[jon 61802]

I have an 1975 85 hp evinrude. I recently got my hands on what I was told to be a 115 evinrude from 1975 and was told it would bolt right up not have to change anything in the lower end. I was comparing diagrams on evinrude dot com and the 115 had a flat back in 75 and the 135 had a curved back and that is what this powerhead has on it. I talked to the person I got it from and was told that he pulled it from a running 115 hp evinrude. so here is my delima if it is a 135 would it fit on the 85 hp like a 115 or am I am pretty much going to have to replace everything.

 

[divinginn]

Re: evinrude powerhead swap 85 to 115 or 135

A friend of mine swapped a 140 block onto his 115 so I would think it would work. The 140 replaced the 135,I think his was late 70s model.

 

[emdsapmgr]

Re: evinrude powerhead swap 85 to 115 or 135

All V4 crossflow blocks are interchangeable in a model year. They all use the same base gasket on the exhaust adapter. Two things to watch for on the early models: the configuration of the base gasket and the shift mechanism under the bottom carb. Base gaskets on engines 1977 and newer are different, when OMC went to the double thermostat housing. The powerhead changed again in 1978 when the shifter under the bottom carb changed. You will also find different mountings for the ignition 4 coils, depending on year. If you are swapping powerheads, make sure you get the correct carbs to go with it.

 

[jon 61802]

Re: evinrude powerhead swap 85 to 115 or 135

ok this has no carbs can I take a 115 carb get the jets and install them into the 115 car and would that work or do I need to locate the 135 hp carbs for this

 

[ezeke]

Re: evinrude powerhead swap 85 to 115 or 135

If you have a set of 115 carburetors, you can use them on the 135 block as they are.

 

[MAW31]

Re: evinrude powerhead swap 85 to 115 or 135

would you not also need a prop with a different pitch?

 

[emdsapmgr]

Re: evinrude powerhead swap 85 to 115 or 135

Crossflow carbs are made in different throat sizes-the size is cast into the front flange on the carb. The larger the carb throat, the more air/fuel that will go into the engine and the more hp it will make. The 85 carbs are small throat carbs (perhaps 1" throats), the 115's are larger (perhaps 1 3/16" throats) and the 135 carbs are the largest at 1 5/16" throat size. The engine will make hp depending on which carbs you use. If you want to make full hp on a 135 powerhead, get some 135 carbs.

 

[jon 61802]

Re: evinrude powerhead swap 85 to 115 or 135

Crossflow carbs are made in different throat sizes-the size is cast into the front flange on the carb. The larger the carb throat, the more air/fuel that will go into the engine and the more hp it will make. The 85 carbs are small throat carbs (perhaps 1" throats), the 115's are larger (perhaps 1 3/16" throats) and the 135 carbs are the largest at 1 5/16" throat size. The engine will make hp depending on which carbs you use. If you want to make full hp on a 135 powerhead, get some 135 carbs.

so you seying that I will tone down this motor and not give it as much hp if I went with a 115 carb. The guy I got it from said it was a 115. the pans on the back are consisten with a 135 so towning it down is more than fine with me I am affraid that it is to much for my boat and if that is all it take that is fine.

 

[crb478]

Re: evinrude powerhead swap 85 to 115 or 135

What is the model number on the round plug on the power head? That will tell you what the motor was/is. The 135 did have the bubble back exhaust, but someone may have added it to a 115. The 115 carbs will work and will likely only cost you on the top end. If you want more power you can look for a set of 135 carbs.

 

[bailey]

Re: evinrude powerhead swap 85 to 115 or 135

A quick suggestion, if the powerhead is complete (not bastardized),why don't you look for the numbers that are usually stamped on the quarter sized frost plug that you'll find on the top of you engine. Usually that number can be cross referenced thus enabling you to know exactly what engine you have.
Bailey

 

[jon 61802]

Re: evinrude powerhead swap 85 to 115 or 135

A quick suggestion, if the powerhead is complete (not bastardized),why don't you look for the numbers that are usually stamped on the quarter sized frost plug that you'll find on the top of you engine. Usually that number can be cross referenced thus enabling you to know exactly what engine you have.
Bailey

I tried that and they are not there. The guy that I got it from said he pulled it from a 115 but I started compairing and it has the bevel pan on it like the 135.

 

[Dhadley]

Re: evinrude powerhead swap 85 to 115 or 135

If the base gasket is the same the powerheads will interchange. The carbs will all interchange and work as produced. It's very doubtful if you'll see any difference between the 115 and 135 carbs unless you're at or near 6000 rpm or more. The 85 carbs will work and will have a better holeshot and acceleration than the 115 carbs but may suffer just a tad on top. Again, it all depends on what your top rpm is.

 

[jon 61802]

Re: evinrude powerhead swap 85 to 115 or 135

well I have 115 carbs on the way. other than that it was pulled from a 75 115 acording from the guy at the marina and that it was a 115 powerhead

 

[beal]

Re: evinrude powerhead swap 85 to 115 or 135

I have a 1975 115 hp. So, do you think I can boost it to 135 just by changing the carbs?

 

[emdsapmgr]

Re: evinrude powerhead swap 85 to 115 or 135

You may want to check the "new" 115 block that you have. It is possible that it is not the same year you think it is. 1985 and later 115 powerheads did have the bubble back exhaust. Those will not fit on your midsection. Look at the powerhead base gasket which is required for your midsection and hold it up to the bottom of the new powerhead to see if it's configuration matches.

 

[coachode]

115hp Evinrude question for you aces. Will a 1978 115hp power head fit on a 1996 115hp engine?Shelled the 96 but have a good 79 power head.

 

[racerone]

They will demand you start a new thread / topic.----This one will be CLOSED>

 

[GA_Boater]

We don't demand anything, but it is closed.

coachode Please start a new thread of your own.