go to steve and let him set it up, worth the money just in gas saved. sounds like your overpropped and set wrong, this will burn more fuel.

Did you get the compression on the engine checked?

I agree with the posters above that say something isn't right. My 98 Astro goes 18'2" @ 1970 lbs dry and, until recently, got 58 with a 150 (no need to expand on that here). I'm no expert, but this sounds more like you lost a cylinder or burned a piston or something. From what I have read, a jack plate/prop adjustment might give you a few MPH, but you seem to be short almost 20. I don't think a jack plate/prop adjustment will make up a gap that big. Does the motor run well. 42 mph at what RPM?

Yep just knowing what RPM's it is turning at Wide Open Throttle under a full load, fully trimmed would tell a whole lot....You are trimming up the motor after you get on plane? Stupid question I know, but you'd be surprised at the number of folks that don't know you are supposed to do this when they get a new rig.........

my rpms are around 4200 at wide open throttle.
and no i am not trimming up when i get on plane.
sorry guys this is my first boat i did not know that.
i have driven several boats before but nobody has ever told me
that.
should my rpms be more than 4200?

You are way off on your rpm's. I am estimating your motor should run about 5500-5800rpm at WOT. At 4200rpm, your motor is loafing along.

thats what i thought too.
is there something i need to do to raise rpms??
raise jack plate a little??
change prop??

maybe check fuel filters??

There is such a big difference in your current rpm's and where you should be, it could be a combination. Not knowing what size prop that is on the boat is problematic from the beginning. You should have the propshaft set at about 3" or so below the pad. That being said, you are short about 12-1500 rpm's and that could be a motor problem.

I think I would have the motor checked by a mechanic first to make sure there wasn't an issue with the internals. Then get the right prop, set the jackplate correctly, and take it to the lake and work experiment with motor height and your trim angle.

Good luck.

There's your problem with your speed ... Trim that baby up till you fill safe and in controll ...

Do you think he can pick 1500rpm's by trimming the motor?

yes will my rpm's come up as i trim the motor up??

and would the fuel filter cause this??

Sounds like my boat. Time for a carb job...

You just need to learn to trim the engine properly as your speed increases. All bass boats will only do about that many rpms with the motor all the way down. Try and get someone to take you for a ride in your boat and teach you how to drive it.