Mercury vs Johnson Power

[Ron_S]

I have a 1966 Merc 110 9.8 and a 1960 Johnson 10 HP. The Johnson seems to put out more power. At least the boat goes faster. What is the real HP rating of these motors?

 

[daveswaves]

Re: Mercury vs Johnson Power

I have a 1966 Merc 110 9.8 and a 1960 Johnson 10 HP. The Johnson seems to put out more power. At least the boat goes faster. What is the real HP rating of these motors?

Both Merc and Johnson rated their engines at the powerhead in the 60,s. The power is as rated, 9.8 and 10. It is unlikely you have the same prop on both and that is why you see the difference. You may have a long shaft merc and a short shaft Johnson. Lots of potential differences....just not HP. If anything Merc advertised lower output than actual so that smaller mercs could beat bigger johnsons.

 

[Ron_S]

Re: Mercury vs Johnson Power

Same length lower unit. Factory props. Will check pitch and diameter.
I had always heard too that motor for motor using advertised HP that a Mercury would leave an OMC in the dust, but the OMC would pull a tree out of the side of a hill.

 

[mr 88]

Re: Mercury vs Johnson Power

Well after you check out prop pitch and max RPM @ WOT the next thing is a compression test. Maybe the Merc is tired and the Johny was just freshened up.Like mentioned the Mercs of that era were def faster than the Rudejohns.I can attest to that as kids we were always swapping motors and racing the other kids in the bay, Merc hands down, but they were a little more tempermental.

 

[jbjennings]

Re: Mercury vs Johnson Power

My '72 merc 110 9.8hp is faster than my various OMC 10hp outboards- noticeably faster.
JBJ