I've been reading all these "28mph unloaded and 26mph loaded" "30mph unloaded and 28mph loaded" posts and it got me thinking.

When I bought my 2010 35hp GDSD, my top speed was 23.4 unloaded. I then changed from a 3 blade prop to a 2 blade prop and my top speed went to 24.5. With 2 other people in the boat, my top speed was 21.5.

Now I've added a Mikuni Carb and Marshmellow exhaust and I can run 27 deep water all day and hit 28-29 in the shallow stuff. But my top speed with 2 others in the boat is still around 22mph.

Just seems like if most people are only losing 2-3mph with a load, something must be wrong if I'm losing 5+mph.

I got the right hull to carry loads well, so its got to be the motor, right?

I have a buddy that owns a shop that was going to do some headwork for me, but after hitting the 27-28mph mark, I wasn't worried about any more speed. But now I'm thinking he needs to take a look at it afterall.

Compression and leakdown test are cheap way to find out if your valves are leaking.

I'd say screw it and send in your heads to BPS after the season and let them send you some Iron Mountain heads.

bbb - you are going to have to increase the compression to get the torque to carry a load at higher speeds. Iron Mtn heads did wonders for my motor.