Correct prop for 1999 Merc 150 EFI

[GlasV162]

Hello,

I have a 1999 Mercury 150 EFI outboard on a Glastron GS 180. It runs great but I'm a little concerned about the WOT
RPMs; with just me in the boat, at WOT it's turning 5200; is that too low? Does anyone know the RPM range on this motor?
Thanks,
John

 

[GlasV162]

Re: Correct prop for 1999 Merc 150 EFI

Forgot to add............it's turning a 21" pitch stainless steel prop.

 

[craze1cars]

Re: Correct prop for 1999 Merc 150 EFI

I believe it is supposed to be 5,000 to 5,600.

I'm not absolutely positive on that...any Mercury dealer would be a better resource...a quick phone call and I bet any service dept could look it up for ya, especially if they knew you were prop shopping....

 

[GlasV162]

Re: Correct prop for 1999 Merc 150 EFI

I called Mercury tech support today & found that 5000 - 5600 is the WOT range. Since I'm on the low end of that (5200) with just me in the boat, will I do engine damage pulling skiers or with 6 - 7 people in the boat? Thanks.

 

[craze1cars]

Re: Correct prop for 1999 Merc 150 EFI

You will not damage the motor. You will also not get max performance/holeshot. Might take longer to plane than you like and your skiiers might drink a lot of water...ESPECIALLY if any of them does deep water slalom starts.

IMO, you should have a 19 pitch prop, especially for that type of fully loaded/watersports application.

It's always smart to have 2 props anyway, one on board as an emergency spare if you hit something and don't want to ruin your entire day...

 

[ufm82]

Re: Correct prop for 1999 Merc 150 EFI

Since you are in the correct RPM range you won't hurt the engine. Granted, you won't see the same RPM when loaded up but you'll be OK. I have a '93 150 EFI engine and run a 19 Tempest when by myself and a 13 Mirage (it came with the boat- I wouldn't have gone that low). WOT is 5,800 with the 19 and it will over-rev with the 13 but when pulling tubes I'm not running at WOT anyway.
Is that stil a 2.5L engine or a 2.0L? The 2.5s will run at the top end all day with no issues- even to 6K. Don't know about the smaller displacement engines.
You said you have a stainless prop- what type? If it is a basic SS prop there is room to play there too. A Laser II will give you good bow lift and good bite when pulling tubes/skiers. A Tempest will give you better top end speed. Keep the 21 for lightweight running an drop to a 17 for pulling tubes- you'll like the lower end power and the grip.

UFM82