How many water intake holes can I safely plug on Merc 150 on a 1400 lb bass boat?

[Bumblebeeman]

I've got a 1991 2.4 liter XR4 150 on a 1400 lb 20 ft Procraft bass boat. The little XR gear case had to be replaced, so now it has a standard 2:1 gear case with 8 water intake holes on each side of lower unit. Top speed is 54 mph. How many of the water intake holes per side can I safely plug?

[billybob]

Plug the top four on both sides. Use a 5/16-18 set screw, stainless steel. Tap holes for that thread, and use red loctite. I sell the s.s.set screws for $2.50 each, but you might find them locally. 319 404 4510

[Mrzip]

Personally. I wouldn't plug any

[Merc 2.5]

Ya I'm wondering why ur wantin to plug em , r u lookin for that last couple mph? 150 on 20ft bassboat well that's a heavy rig , the higher u get the motor the less lift and trim u will have , if u need positive trim to reach wot the it mite hurt u

[SS Minnow]

I am thinking the same way as the last two guys.

Are you running a water psi gauge? Accurate tach and speedo?

The height I run my motor at I have plenty of psi and optimal top end speed. If I raise my motor anymore, I lose speed. 3/4" higher and I lose psi while turning and 10 mph in the straight line.

Your results may vary, but higher with the motor is not always better. Just my experience.

[rgsauger]

Definitely start with the water pressure gauge. If you're needing more water, the little side scoops really do work to force feed it more water. If you run in heavy grass and weeds, pass on the scoops.

[tlwjkw]

150 ona 1400 lb. pro craft!.. leave it be.. you won't gain 1 i o ta................ water pressure gauge is a must.... play with props n height with whatcha got...... jmo

[hsbob]

make a set of merc scoops. do a search on this site and you'll see pics. as stated above you need a water psi guage when u start play with the PU.