power hwad swap

[marty-a]

Will a 1977 85 hp Evinrude power head bolt up to a 1983 115 hp mid section. looking to update the trim system from the outside pump to the internal system. Marty

[dan-in-tn]

It is not a bolt up. The bolt pattern on the two powerheads is slightly different as evident by the different base gaskets, but it has been done. It require a bit of work. Filling the existing holes in the powerhead and re-drilling using a late gasket #342513 for a template.
The late style trim is sure worth it.

Dan in TN

[dan-in-tn]

Marty; I might have forgotten something more important than bolt pattern. Does your ’77 motor have a multi spline driveshaft or a 4 flute shaft at the top? Your gearcase won’t fit the newer midsection and of course a newer gearcase won’t fit your old powerhead if it has a 4 flute crank. Hope that makes sense. ’77 was the change over year for the 140hp V-4 & 25" 85 & 115hp motors to the new midsection with new trim. It was 1978 before the 20" 85 & 115 went the new style parts.

Dan in TN

[marty-a]

Thanks Dan, not sure about the drive shaft as it was serviced just prior to my purchase. Was having problem with t&t leaking and found 3 stripped fittings, repaired and no leaks but can’t purge air out of system. Sweet running power head though.

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