2002 Lund 1675 pro sport

Ok guys I have a Lund pro sport with a 115 merc 2 stroke looking for a little more speed I have a 3 blade aluminum 17p on it now 5300 rpm 39mph

It seems you should be spinning that prop easily with a 115. By the book I think you need another 500 rpm’s at least to get it the sweet spot. To do that you need to drop a couple inches and that’s even going to slow you more. Just curious, have you weighed that boat for water logged flotation? Is it loaded heavy? I’m kind of at a loss for suggestions at the moment.

I haven’t got a weight on it should be close to factory. Only things I have it a 24v trolling motor up front an a helix 7. And a Onix 10 at the steering wheel.

The Merc site says a 13 x 18 Vengeance 3 blade stainless should go 41.5 mph at 5125 rpm’s. I know that doesn’t take load in consideration. Do you trim the motor all the way up? Have you checked to see if your motor was mounted in the right hole? Just some things to check. Motor Cav plate should be flush or above the hull no more then an inch. Some guys like them set higher but usually in a jack/plate situation. When I test I run a full tank of fuel, my gear, and me, every time. This way I have something to compare it to. I use GPS for speed, and hopefully the tach is correct. Re-propping is always a pain in the @ss unless you have some dealer or friends that have try props.

I don’t think you will see much change. you don’t have a lot of rpms to work with. whats a mph or 2 anyway? if your hole shot is decent stick whit it. if that was poor goto a 15 degree but would lose a mph or 2.

Whens the last time you cleaned the carbon out that machine? Johnson has a engine tuner for their motors, maybe Merc does too. If the engine hasn’t been tuned up in awhile perhaps some going over will get you the extra couple hundred rpms you’re looking for.

The boat goes to the shop every year to get the motor gone thru. The motor does cave a little but I trim it up as far as I can.