Rpm's

[Father's Day]

Hello everyone hope you are all ready for a great weekend on the water . I was out the other day with an old timer and as I was pick up speed he had a speedometer on his phone. He asked me with my RPM's were, I told him 5000 he said I should bring it down some, Its not good to run so high. I was going about 32 mph and I brought it down to 4500 and was going 27. I have a 2000 Merc 150 EFI she was running perfect at 5000 and also at 4500 I was on plane and smooth as could be. Any thoughts on this would be appreciated.
Thanks and be safe

 

[SkunkBoat]

he didn't want to go fast...
You can look it up but I'm guessing WOT max rpm is suggested at 5500-6000?

 

[Father's Day]

he didn't want to go fast...
You can look it up but I'm guessing WOT max rpm is suggested at 5500-6000?

That's kind of what I thought too I need younger friends
Thanks
Enjoy your holiday

 

[PointedRose]

It’s a 4 cylinder engine. I have a 6 cylinder I/o and my WOT is 4000rpm. Your friend is probably just mixing apples and oranges.

 

[Father's Day]

It’s a 4 cylinder engine. I have a 6 cylinder I/o and my WOT is 4000rpm. Your friend is probably just mixing apples and oranges.

It’s a 4 cylinder engine. I have a 6 cylinder I/o and my WOT is 4000rpm. Your friend is probably just mixing apples and oranges.

Its actually a 6 cylinder and he has been around boats his whole life that's the only reason I'm asking

 

[PointedRose]

Its actually a 6 cylinder and he has been around boats his whole life that's the only reason I'm asking

Oh ok. The specs for the new 150 mercury show inline 4 cylinder

Fourstroke 75-150hp Outboard Motor

FourStroke

www.mercurymarine.com

 

[seasick]

In general , he is correct in that motors run continuously hard towards the top end of the rev range will 'age' faster and may experience faster wear.
It isn't so much the revs but rather the power demanded by the conditions. Even at lower revs in certain conditions, too much demand for power can put excessive strain on a motor. (think about towing something like a floating dock or a larger boat.
There are times when you want to run towards the limit for short periods as I do at times to 'clean' the hull.
If I were looking at a dump of engine data before buying a motor (or boat with motor), if the motor was run at high revs for a large percent of the motors usage hours, I would be very leery about that motor. I have known boaters who only know 2 throttle positions, idle and WOT and they beat their motors and hulls to death.
Your motor is 20+ years old and if you have had it for a long time and frequently run it at high revs, I guess it didn't really harm the motor much

 

[seasick]

I want to add that most modern motors are rev limited which protects it from damage. Older motors may not be and over revving can cause some serious, sometimes, catastrophic damage.

 

[ScottyCee]

Outboards are made to operate in their entire approved RPM range. Many consider it a best practice to run at WOT for an interval every outing. It used to be necessary to “blow the carbon out” of two-strokes, but I have a feeling that’s less important with the modern powerful engines of today..

 

[SkunkBoat]

19 ft boat 150hp EFI 2 stroke? My gut says it should easily hit 40mph at WOT with the right prop.
I don't think he was pushing it. If you were at WOT when you were at 5000rpm at 32 mph, you have problems.

 

[Toothpick 10]

I was looking at the performance information that I got from GW for my boat and motor this morning. For my set up, there is a big drop in fuel economy from 4,500 rpm to 5,000 rpm. Every set up is different, but you may find that 4,500 rpm is more economical for you.

 

[Father's Day]

19 ft boat 150hp EFI 2 stroke? My gut says it should easily hit 40mph at WOT with the right prop.
I don't think he was pushing it. If you were at WOT when you were at 5000rpm at 32 mph, you have problems.

Ok my bad just talked to my buddy I was at 37 with 5000rpm and 32 at 4500 hope that makes more sense motor was humming along

 

[Father's Day]

Ok my bad just talked to my buddy I was at 37 with 5000rpm and 32 at 4500 hope that makes more sense motor was humming along

If a different prop makes a difference any recommendations would be appreciated