Wrong Prop

[Kam Ma]

I just bought a used 2005 tracker tx175 with 60hp 4 stroke merc efi. Engine is strong but I keep reading about all of these people going 30-35mph! My boat has a Solas 3 blade 13.75 - 13 pitch prop. I have yet to WOT because the engine beeps as the tach is over 7K. At 6500 rpm the best speed I can get to is 24mph, at 6000 rpm I'm going about 21mph. Hole shot is good, up on plane in just a few secs. So I'm pretty sure I'm not propped correctly. I have a light load no heavy stuff on the boat so my guess is fully loaded I'm maybe around 1300lbs? I'm not looking to break any speed records but it would be nice to go a bit faster without a 20 sec hole shot, maybe 30mph at 6000rpm with a 7-10 sec hole shot, is that reasonable? PLEASE HELP!

 

[G8rmac]

Do a search for the specs on your motor. I see some things that show max rpms at WOT on that motor is 5500-6000. If you are over 7000, you are definitely under-propped. Check the link below, it should help you find the right pitch.
http://www.mercurymarine.com/propellers/prop-selector/#

 

[Sean Troy]

If you need a 16 p. I have a deal for you.

 

[Matt Kling]

1st ensure your tach is accurate. My tracker tach was ALL over the place and not reliable... So I got a Smartcraft Gauge. THEN - i was able figure out my exact rpms/speed (reliable gps) and pick a prop accordingly.

 

[Scott Hammer TOXIC]

Also, always test your boat fully loaded. You could call the individual you bought it from and see what they ran and why. They may have wanted holeshot and not top end.

 

[Kam Ma]

Thanks for the info guys. Went to that merc site, suggested a 4 blade spitfire prop but not the pitch. Any suggestions?

 

[Sean Troy]

First make sure you are trimming the engine correctly. Looks like you'll need a Spitfire at 10P or 11P

 

[Matt Kling]

If you are hitting 6500-7000 rpms (if your tach is accurate) - you'll need to go UP in pitch size... probably to a 16 pitch... that will put you in a nice rpm range.



Here's why I think your tach is incorrect. If you got 24 mph at 6500 rpms with that motor and a 13 pitch prop - you are seeing a 45% prop slip. That's WAAAY high. My 60HP Merc has about a 5% prop slip. I would test your tach first before you go on to change out your props.

 

[Sean Troy]

Mattfish is correct. I went the wrong way.

 

[Kam Ma]

Ok I'll have my tach checked at the next service. I think the tach is ok b/c at WOT the engine beeps which I assume is the rev limiter kicking in, and that starts to happen at just about 7000 rpm. Lastly do you guys recommend the 4 prop or 3 prop set up?