REVISED What is the difference in a '04 Johnson 90hp. and a 115hp? Mechanics secret?

[mtcaves]

Hello,

My mistake on the previous listing.

I have a 2004 Johnson Outboard 2 Stroke Saltwater ed. Model # J90PLSRR, carbureted, not 4 stroke as previous listed.

Could you tell me the difference in the 90hp and the 115. I know the powerheads are the same, ECM are the same.

If anyone knows, a reply would be appreciated.

 

[JB]

Re: REVISED What is the difference in a '04 Johnson 90hp. and a 115hp? Mechanics secr

You "know" the powerheads are the same? Probably not true. BRP isn't telling, but the typical "tuning" of a given block to get a particular peak HP output includes some or all of the following:

Compression ratio
Port size and/or timing
Exhaust geometry
Ignition advance curve
Carb venturi diameter
Reed size and flex

And perhaps a few other tweaks that I have used in racing engines but won't tell about because they greatly risk reliability.

 

[mtcaves]

Re: REVISED What is the difference in a '04 Johnson 90hp. and a 115hp? Mechanics secr

You "know" the powerheads are the same? Probably not true. BRP isn't telling, but the typical "tuning" of a given block to get a particular peak HP output includes some or all of the following:

Compression ratio
Port size and/or timing
Exhaust geometry
Ignition advance curve
Carb venturi diameter
Reed size and flex

And perhaps a few other tweaks that I have used in racing engines but won't tell about because they greatly risk reliability.

Thanks for the info. A guy who works in my RV service department works on outboard motors; I had no idea that he worked on these. He told me the differences and said he could take care of it for me. Thanks for all the replys.

 

[flabum]

Re: REVISED What is the difference in a '04 Johnson 90hp. and a 115hp? Mechanics secr

I looked up that motor on the BRP site. The block and heads are different part numbers. Porting and compression are different along with carbs and maybe timing as well.