1997 Sun Deck 240 top speed

[rexford]

Hello. I am buying my parents 1997 Sun Deck 240. When it was new the speedo read 42-43 top speed. The engine was rebuilt a couple of years ago. It now will hit 34-35 on the speedo and gps. Does anyone know what it should do? It has the 5.7 mercruiser and I'm pretty sure it is the base version. I am just wondering if I need to chase horses that have escaped. By the seat of my pants if feels slower but that could be psychological.

 

[jimandsue60]

You have to answer some questions before we can help you:

Is the bottom painted?

Was the bottom painted when it was new and could do 42-43 MPH?

Is the bottom clean?

What was the max RPM when it could go 42-43 MPH.

What is the max RPM now?

Has it had a compression test done lately?

 

[rexford]

The bottom has never been painted, now or when it was new. It had been in the lake for a while the last time it drove it so there was a small accumulation of scum but not a lot. Unfortunately, I do not know the RPM before or now (it is out of the water). When my father took it in recently the mechanic couldn't find anything wrong with it, but I do not know if he did a compression check. It's got about two years on a rebuild. I just found out that the trim tabs were broken and I'm hoping they were stuck down, slowing it. Any input is appreciated. Rex

 

[rexford]

I forgot. The prop spun the last time I took it out. Could it have been failing causing a loss of power?

 

[rexford]

I took it out this weekend and the horses have returned. 40 mph on speedo and gps into the wind, 2 adults 2 kids on board and half a tank of gas, top up. 42 on speedo with the wind. Must have been slime or the trim tabs.

 

[jimandsue60]

I took it out this weekend and the horses have returned. 40 mph on speedo and gps into the wind, 2 adults 2 kids on board and half a tank of gas, top up. 42 on speedo with the wind. Must have been slime or the trim tabs.

Wow that was an easy fix! Have fun.

Jim