newer 90hp ob or older 115hp ob

[tarip]

I'm looking at a Bayliner that I can get at a good price. it has a 2001 90hp Merc on back. I have access to a cheap 115 Merc (1979) that i could theoretically toss on back of the boat as well. my question is is it worth it to do the swap? is there going to be that big of a difference? or are they goin to be pretty similar? i know the newer 90 is rated at the prop and the older 115 at the powerhead. That is the reason i was wondering. thanks!

 

[Cannondale]

Re: newer 90hp ob or older 115hp ob

While that "extra" 25 hp may look appealing, there's a bit of work involved in changing engines esp. in this case, and it rarely goes smoothly. I'd personally let the motor that's on there just stay. Lot less cost, work, and frustration.

 

[79Merc80]

Re: newer 90hp ob or older 115hp ob

Cannondale is correct. Not only re the electrical connections different, but the mounting bracket also. Mercury was the last to change over to the "Standard" mounting brascket and they did that in 1984 (For the inline 6's anyway). So you will have to fill the current holes in your transom and drill new ones. Performance wise, you would gain little. The only thing that the 115 inline 6 has over the 90 inline 3 is low end tourque. Also, if the 115 has power trim, it's the old style that has the pump inside the boat, so you would also have to cut a hole in the engine well for the hoses.

I love the inline 6's, but if I were in your shoes, I would leave it with the 90. Maybe get the 115 and if the 90 ever craps out on you, then switch it over.

 

[ezmobee]

Re: newer 90hp ob or older 115hp ob

I wouldn't even consider that swap for the reasons mentioned above and you're own mention of the HP rating changes. I think you'd gain little and that '01 should be a fantastic engine.