9.9 powerhead on a 7.5 chassis?

[samleen18]

I recently got my hands on a johnson 9.9 powerhead from the late 1980s. my current outboard is a 1982 evinrude 7.5. the bolt pattern on both motors is the same, so I am wondering if I can fit the 9.9 powerhead to the 7.5 chassis to get a boost in power without adding a lot of weight.

the boat is an avon rover r2.80 that the 7.5 struggles to get on plane

 

[jimmbo]

Welcome to iboats
I doubt the 7.5 Gearcase is robust enough to handle extra Torque of the 9.9, and Propping could become an issue

 

[samleen18]

Welcome to iboats
I doubt the 7.5 Gearcase is robust enough to handle extra Torque of the 9.9, and Propping could become an issue

evinrude did make a super10 that I read was the 9.9 powerhead on the 7.5 chassis. I couldn't find much more info on it

 

[racerone]

???----Not sure how you determined that a 9.9 HP will fit on the 7.5 HP midsection ----Because it will not fit !!-----And the " super 10 " was not a 9.9 on a 7.5 midsection.-----Sorry --you are sadly mistaken on these 2 topics.

 

[kbait]

Agree w/racer^.. powerhead base gasket 9.9 vs 7.5

 

[ct1762@gmail.com]

as mentioned not remotely the same. you could possibly downgrade to a 4.5/4 hp deluxe though!