115HP and 85HP interchangeable parts ?

Moody Blue

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Have a buddy that cooked the top end of his motor last weekend when the W/P failed. Have located a 115HP motor that is missing the bottom end but it looks identical to the 85. Wondering if we could take the 115 top end and bolt the 85 lower unit to it. Here are the numbers;<br />85hp - s/n C4495L model 85EL77S<br />115hp - s/n G50765 model 115393M<br />Any help would be much appreciated, thanks.
 

Moody Blue

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Re: 115HP and 85HP interchangeable parts ?

Forgot to ask, can anyone confirm the years of these motors?
 

Dhadley

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Re: 115HP and 85HP interchangeable parts ?

The 85 is a 1977 Johnson and the 115 looks like a 1973 Evinrude.<br /><br />All those parts (powerhead & lower unit) will interchange. Now -- the 1973 V4's were an animal all to themselves as far as the powerhead components go. The block, crank, rods and pistons are different than a 1972 or a 1974. Just remember that if you have to rebuild the 115. The powerhead assembly will bolt on the 77 midsection as well as the 73. The good gearcase will bolt to either midsection.
 

Moody Blue

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Re: 115HP and 85HP interchangeable parts ?

Thanks for the quick reply. How can I decode these numbers to determine years ? Is there a web site I can refer to ?<br />I checked the link you provided and the part numbers don't match as anticipated but that doesn't necessarily mean the parts won't fit. Any other way of determining compatibility ?
 

Jcstratt

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Re: 115HP and 85HP interchangeable parts ?

I was looking at the part numbers of things like the exhaust tube housing, adaptor, driveshaft, etc. and they match. You can do an "advanced" search with the model number (or even a part number) and it will show you where it goes and what year. I don't know much more about it than that other than dhadley knows what he's talking about for sure.
 

Dhadley

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Re: 115HP and 85HP interchangeable parts ?

Everything except the powerhead internals are the same. Everything should be a direct bolt up.
 

Dhadley

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Re: 115HP and 85HP interchangeable parts ?

Oh -- the 115 is a 3.500" bore and the 85 is a 3.375" bore so the heads wont interchange. But the blocks still use the same base (mounting) gasket.
 

Moody Blue

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Re: 115HP and 85HP interchangeable parts ?

Fantastic, you guys never cease to amaze me. Once again you come thru with the details and info I thought would be impossible to find. Thanks so much, I think we have a solution to the problem at hand. <br /><br />One more thing, the '73 lower unit originally was an electric shift and the 77 is mechanical. Can the two be interchanged ? Is it a matter of transferring the shift rod and linkages from the '77 to the '73 lower unit ? Is oit that simple ?
 

ledgefinder

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May 2, 2002
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Re: 115HP and 85HP interchangeable parts ?

Hold up - the 1973 115 used a mechanical-shift lower unit. If the 115 you're looking at had a hydroelectric lower unit, it may be actually a 1969-1972, regardless what the tag on the midsection says. Are there four coils to the ignition system, or just one?
 

Moody Blue

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Re: 115HP and 85HP interchangeable parts ?

Just from the quick look at the motor I recall 4 coils. Is there anything on the block that will provide better year determination ? The guy selling the motor (115) said it had an electric shift but he may be mistaken. If the lower unit is missing is there any way to tell what type it may have been?
 

ledgefinder

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Re: 115HP and 85HP interchangeable parts ?

The "four coil" ignition means a 1973 or newer, mechanical shift V4. The hydroelectric shift V4s were 1969-72. Everything should bolt up to the 1977 85hp V4. (As DHadley points out, the 1973 has some unique parts internal to the powerhead.) If you want to be absolutely sure, there's a factory freeze plug with the motor's model and serial numbers, on top of the port (starboard?) bank of cylinders, cleverly hidden by the brackets for the ignition coils. The motor should have a red master control plug, not black.<br /><br />The 85 was significantly under-rated; 115 won't feel as much stronger as you might think. The 115s do wind out nicer and make a good bit more noise on a test prop (5200+ vs around 4800 rpm for the 85hp), but it's not all that noticeable on a hull except at the top end. The 115s also tend to burn out easier too, so check the compression carefully before you buy.<br /><br />The powerhead swap is reasonably easy, as long as neither motor has seen too much saltwater use. Watch the two nuts under the exhaust plate at the rear of the motor. If anything is too corroded to turn out easily, DON'T FIGHT IT & STRIP THE FASTENERS. Lots of handy tricks if anything's corroded, post back if you need help.
 

Moody Blue

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Re: 115HP and 85HP interchangeable parts ?

OK thanks for the update. Looks like we are in good shape now. Will be sure to do a compression test before buying.
 
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