modifying a crank rated 9.9 into its shaft rated counterpart?

[samleen18]

I have a 1974 evinrude 9.9 and a late model parts motor. I already swapped it from points to CDI and put the new carburetor on it. I read that there is a tuned exhaust pipe on later models. how do I tell if my parts motor has one?

what else can be done

 

[flyingscott]

The exhaust tuner will be round if it has the newer style. Old style is square

 

[flyingscott]

Those motors were always powerhead rated.

 

[samleen18]

Those motors were always powerhead rated.

I thought that OMC switched to prop rating in the late 1980s?

 

[racerone]

Not sure if they changed the rating on the 9.9 / 15 models.----Perhaps they did in 1993 when displacement increased on the 9.9 / 15 HP.

 

[flyingscott]

I thought that OMC switched to prop rating in the late 1980s?

The 93 and later may have been. OMC never prop rated their smaller engines in the 80s

 

[samleen18]

The exhaust tuner will be round if it has the newer style. Old style is square

the parts motor has the round exhaust. I suspect it may be a 15 with a 9.9 decal.

 

[flyingscott]

Later 9.9s came with the round tuner. Later 9.9s got everything the 15 did except the csrb.

 

[samleen18]

Later 9.9s came with the round tuner. Later 9.9s got everything the 15 did except the csrb.

turns out the parts engine is a 15 with a 9.9 decal according to the numbers on the block