150 Merc EFI – Max RPM ?

Can anyone tell me what the top end RPM range should be for a 150 Merc EFI? I want to be careful not to over do it if the RPM’s are running too high. With just a few little dings in an aluminum prop, Ive noticed the performance isn’t what it once was. I’ve picked up another rebuilt prop with the same pitch ( 19 ) as a back-up, but havn’t usedit yet. It seems like the RPM’s are running at 3200 at 25mph. thanks Dave C.

The Mercury web site lists the RPM range of a 150 EFI at WOT at 5000 to 6000 rpm’s. Pretty wide range, lots of different prop opportunities in that range. I would suggest using their prop selector feature that considers the motor and the size and style of boat. A lot depends on your intended use. Ski boat vs trolling, vs WOT running for top end or out of the hole capabilities? The link to the 150 EFI information is on this web page.
The knicks in your prop can cause turbulence and unecessary vibration, especially when run at higher rpm’s. Those knicks can ruin a propellor if it is run for a long period of time. If you never go over 25 mph, don’t worry about it.

That motor will run all day at 6000. You want it propped in the 5800-6000 range.

I would not be too concerned with a performance drop during hot muggy weather. When the water cools off a bit and the temp drops, you may get that extra MPH back.

Jon J.

Thanks for the feedback. Here’s another question.
Quite a few guys run with SS Props. What are advantages with SS vs Alum.? Seems like SS is in the $350 range. Is it worth it? thanks Dave C.

Asking for another opinion? Ok here you go. I used to go through 1 or 2 aluminum props every season until I got my first SS. In the long term my costs went down. A little bump on a log or stump will usually never ever show up on a SS prop, whereas an aluminum one will need repair for certain and replacement in the worse case. I have only had to have one SS prop rebuilt and that was after hitting a submerged log at about 45 MPH. One blade came away with a thumb sized cup in it. Until something new comes along I will always have SS.

Although ss props are a lot more durable it is necessary to realize that an aluminum prop absorbs the energy of the blow much better than stainless. Stainless tends to transmit that energy to the shaft and lower unit possibly causing more damage. My two cents.

Gator Hunter

You will also have better hole shot, better top end, the boat will hold better in tight turns. In other word, overall improvment in handling and performance.

J.