max rpm question on 175 johnson

[bg175]

Max rpm is about 4,000 and 40 mph. What should the max rpm be for my 1977 175 johnson. I would appreciate any help.

 

[Dhadley]

Re: max rpm question on 175 johnson

You should be at 5500 as a minimum. 5800 won't hurt anything, in fact it's better on the motor as far as life expectency.

 

[emdsapmgr]

Re: max rpm question on 175 johnson

You are over propped. That engine was factory rated to operate between 4500 and 5500. The normal recommendation is to run at the upper end of the normal operating range. Follow Hadley's advice and you will be ok.

 

[bg175]

Re: max rpm question on 175 johnson

thanks, i was goin to the water today, i have a prop that came with the boat. It looks the same as what is on the unit now, as far as the pitch anyways. I'll change it out and let ya know. Do props usually have the pitch marked on them somewhere? Thanks for your time.

 

[bg175]

Re: max rpm question on 175 johnson

After cleaning the black soot from inside the prop, i could tell that is was a 14.5 * 23. The other prop was 14.5 * 19. It performed much better. WOT is about 5500, 50 mph. The throttle is really responcive. Thanks for your time.