Jetting a Johnson 175

I have heard that by changing the jets and reeds in this motor I can go to 225 horses. My motor is a 1979.

Tim Love


The porting, heads, reed stop height and a host of other things are different. Your motor is a low compression, low ported version of the old 235. Changing jets will do nothing in terms of your goal. You would have to spend several thousand dollars to mod the motor to make 235 hp. Would probably be cheaper to trade-up.




Please submit whatever questions you have to  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Mark C.


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