Re: Can I get my money back?
Howdy,
There may more going on here than meets the eye......
I did a little searching around and Stingray claims the 240CS (although it's a 2009 model @around 4200lbs + fuel + 1 person) will do 43mph with a Volvo Penta 4.3L MPI V6[225 prop hp] & 1.66:1 SX drive, with a
stainless steel 19" prop. (which WILL give you better performance than an aluminum prop)
http://www.stingrayboats.com/products/models09/performance_options.pdf
I can't pull the 1999 Mercury 5.7L MPI hp out of the air right now but it would probably be at least 260-280 hp so it might be conceivable with the
right drive ratio a 19" pitch prop would be correct.
In the last 10 years someone could have rebuilt or changed the drive because it was damaged, stolen, etc.....and put the wrong (different) ratio on it. (or maybe the original dealer swapped it and it was wrong from day-one!)
Sales people sometimes do strange things and lot of them are are about as smart as a rock!!
So for that engine to run only 4600 with a 15p prop on it tells me that it's NOT developing full HP
if everything else (weight, drive ratio, bottom cleanliness, etc)
IS OK.
The drive ratio could be wrong. Don't use any placards on the drive because in the last 10 years someone could have put different (ratio) gears in it from original.
I am guessing that the drive
should be a ~ 1.50:1 ratio for an MPI V-8.....
But who knows? a lot could happen in 10 years.....
Using the G0-Fast prop slip calculator A 1.36 drive + 15p prop would give you approx 40mph at 4600 rpm (15% slip)
This is all "Ball Park " stuff......It is by no means an exact science. Your boat may indeed be "overweight" ......
Drive it over a scale to check.,
Turn the engine by hand (pull the plugs) <in gear> to count engine revolutions and have someone count prop revolutions to determine the EXACT ratio. (ENG revs/Prop revs= ratio)
Do a compression check to
help determine if the engine
is developing full rated power.
When you know those simple things you can narrow some of other things down.
The shop should have determined if the fuel tank/anti-siphon valve/lines/filter/injection etc had any problems.......
Cheers,
Rick