Question for 175 Merc. owners

[Ole1855]

Merc. owners, I recently bought a new boat with a 175 EFI Merc., I'm wondering if any of you with that motor can tell me what rpm is a good range to trim to so I can run at the best top end or cruising speed.

Ole

[ChuckN]

From the people I've talked to, 5500 RPM's at WOT is preferred. Full trim, WOT I'm hitting the 5700 range at 55mph.

My desired cruising is 4100 RPM give or take at 43mph. I'm running a 23 pitch Merc Lazer prop.

Hope that helps?

[Ole1855]

Come on guy's there's gotta be some Merc. owners out there that can help me out.

Ole

[Hugo]

Ole,
I'm running the same as Chuckn - 5700rpm wot. 55-57mph. Cruise about 4600rpm 45-47mph

Dave

[Ole1855]

Thanks

I appreciate it.

Ole

[PerchJerker]

My 175 EFI runs a little lower rpms - something like 5300 or 5400 if I remember right. Speedometer says 57 mph but the gps says 52 or 53 mph. Prop is a 23 pitch Hi 5. I've been very happy with that motor!

[Ole1855]

I have a High 5 21 pitch, it seems that 5300-5500 seems to work the best, I was just wondering what everyone else runs.

Thanks for you input.

Ole

[PerchJerker]

Just an fyi for you guys, my motor is on an Alumacraft. A couple years ago I brought it to their plant in St. Peter to have them take care of a few minor things on the boat. I asked them about props - I was thinking about trying a 4 blade Laser or something like that to get a little more bow lift and a little more speed. Their engineer, a great guy name Vern, took my boat out and lake tested it, including using a radar gun to check the speed. His recommendation was that the boat ran almost perfect with the Hi 5, and to not make any changes. I don't know if that helps any of you guys or not, but for me it was nice to hear.

[ChuckN]

Have any of you tried a 3 blade? Why a 4 or 5 blade prop? If these props give you more bow lift, I guess my boat gets too much bow lift as it is with a 3 blade. Just curious.

[PerchJerker]

I bought my boat when it was 1 year old - it had been set up and used by a guy on TV.

The EFI is 400 lbs. I've also got a 4 stroke kicker that's another 100 lbs. And a transom mount electric motor. Combine that with a battery, anchor, livewell, etc. in the back and that's a lot of weight.

5 blade props are designed to give more stern lift. They get all that weight out of the water so the bow doesn't ride high, and they pop you out of the hole and up on plane RIGHT NOW. But you'll lose a few mph vs. a 3 blade prop.

3 blades give you more speed, but it takes longer to get up on plane. With a heavy stern a boat with a 3 blade might ride with the bow higher than it could/should be.

4 blades are a compromise between the two. This is a big generalization, but usually walleye boats and multi-species boats run with 4 and 5 blade props, and bass boats and smaller boats run with 3 blade props.

At least, this is how it's been explained to me by guys that sound like they know what they're talking about.