Is it bad for me to run @ 4000 RPMs for extended times?

[ZmOz]

I have a '74 150HP Mercury inline 6. Because of the obscene amounts of fuel this thing uses, I like to cruise around at about 4000 RPMs. Is it bad for the motor to go that slow for long periods? Would it actually be better to be around 5-6000?<br />(also at WOT I get around 6600 RPMs, so I need a different pitch prop)

 

[Dhadley]

Re: Is it bad for me to run @ 4000 RPMs for extended times?

No wonder you burn a lot of fuel!!!!

 

[Chinewalker]

Re: Is it bad for me to run @ 4000 RPMs for extended times?

Hi Oz,<br /> If 4000 revs is a comfortable cruising speed, then by all means run it there. The only time it's not a good idea to run it like that would be if that was the wide open throttle RPM, in which case the motor would be lugging down to 4000 while trying to reach it's rated WOT revs. Kinda like driving around town in 5th gear all the time. You may find your cruising speed changes when you get the proper prop on your motor, dropping it down to 5500-6000 revs maximum...<br />- Scott

 

[ZmOz]

Re: Is it bad for me to run @ 4000 RPMs for extended times?

Should I worry about leaving it between 5 and 6k for more than a few minutes? I know a prop will help out with gas mileage, but it's still going to burn twice as much as a big block chevy...

 

[grandx]

Re: Is it bad for me to run @ 4000 RPMs for extended times?

get is propped right so you don't fall below or exceed the reccomended WOT RPM range and run it at any level you like for as long as you like.