speed

[Charger25]

Hey Guys ,got a question. Been rattling around in me brain for a while. I'm gonna try to make this as short as I can.
A while back I was given an early 90's 25 hp rude that didn't run well at all. One of the things I did was to get the head milled at a local shop. They took off about 20 ths. I think. Not long ago a bud of mine and I were out on the river with our wives.

His boat: 14' flat bottom jon, 25 hp 4 stroke Suzuki, both brand spanking new. Gear was one battery, cooler,anchor, tackle and 2 people.(him, 170 lbs, her 115)

My boat : 16' semi-v 25 hp 2 stroke Evinrude w/well used prop , gear was , battery, trolling motor, cooler, anchor, tackle, 2 people. ( me 190 lbs, wife 125)

Being competitive, we raced of course :LOL2: neither one of us could out run the other. We actually ran side by side at WOT for a while. I know hydrodynamics of the hull have alot to do with it as does the power to weight ratio. But, by getting the head shaved did the compression thus the HP increase that much ? I'm thinking he should've out run me due to heaver boat and older motor with a worn prop.

 

[Stumpalump]

It's on! You must beat him! Cleaning bottom, filing prop, removing every last ounce of weight out of you tackle and tool box. Knocking off a few pounds yourself and sliding an extra shim under the the engine to get that freshly smoothened up skeg out of the water. Open up the holes in your cowl and tweaking that timing screw to milk the last .1 mph out of it is part of the obsession. You must destroy him! Nice work on the head!

 

[lckstckn2smknbrls]

Stumpalump » Sat Jul 05, 2014 10:40 am[/url]"]It's on! You must beat him! Cleaning bottom, filing prop, removing every last ounce of weight out of you tackle and tool box. Knocking off a few pounds yourself and sliding an extra shim under the the engine to get that freshly smoothened up skeg out of the water. Open up the holes in your cowl and tweaking that timing screw to milk the last .1 mph out of it is part of the obsession. You must destroy him! Nice work on the head!

Jack plate.

 

[Ranchero50]

Not enough info to give an honest answer... As said above, motor setup alone can make or break the setup.

 

[Captain Ahab]

Stumpalump » Sat Jul 05, 2014 10:40 am[/url]"]It's on! You must beat him! Cleaning bottom, filing prop, removing every last ounce of weight out of you tackle and tool box. Knocking off a few pounds yourself and sliding an extra shim under the the engine to get that freshly smoothened up skeg out of the water. Open up the holes in your cowl and tweaking that timing screw to milk the last .1 mph out of it is part of the obsession. You must destroy him! Nice work on the head!

YES!

 

[Charger25]

The head was milled due to being warped,it was like that when it was given to me. Guys, not looking to be a speed demon here :LOL2: I got it running to be dependable. It will run a solid 30 mph when loaded like what was said according to GPS with the pin in the 3rd hole. My wife was sitting all the way up front, I know if she was in the middle seat more of the boat would be out of the water thus more speed. I just thought that he would be able to out run me given his new motor vs my 20yr old one along with a heaver boat. I guess I need to do a compression check, other motors of this age and HP that I have worked on have been 90 to 125 psi. Right now its at another friend of mine it using it while I get his 25 up and running.

 

[Kismet]

There's a few old fossils who kinda maintain that a 2 stroke Evinrude may be the best small boat motor ever conceived. I'm one of them.

If you had not raced, and just presented the information, my guess would have been that it would be a wash, depending on the set-up.

And, in my unsolicited opinion, you have the better rig.

Have fun, be safe.