You could try contacting a Merc Dealership, but I doubt the Part is available. Your best bet is just find another motor, in better Condition, and keep this one for parts.
Weren't you trying mix and match Power Trim Systems between this motor and a 44 inch 50hp?
The 4.3 is not going to be a Rocket, or a Speed Demon, in a 21 footer. To get a seriously better Hole Shot, you are gonna need to lower the Pitch to where you will be over revving the Motor, more than a bit, at WOT.
Did you buy this boat new, or used?
Propshaft and Driveshaft are two separate shafts. There are a Few Bearings on the Driveshaft, a few other items that can inhibit rotation
You are gonna have to drop the Gearcase to replace the Water Pump Impeller. Do that and see if the Crankshaft rotates
Unless you are running quite aways outside the WOT Range, adding/subtracting Pitch, within the same Prop Line, usually results in very little difference in Top Speed, but noticeable differences in Hole Shot. Changing to a Higher Performance Prop Model, can allow changes in Setup, which can...
You just said you were gonna take them out and replace them again.
I don't care about the Old Pics, I would like to see what the Plugs that were just run, look like
Phones, laptops, Cameras, actually anything with a Li-ion Battery are not, by Law, allowed to be in Checked Luggage. Cabin Fire Extinguishers are handle these kinds of Fires, but not the Suppression Systems in the Cargo Holds
Raising HP by hopping up the engine, may result in a bit more Top End, but that usually means poorer Acceleration.
More Displacement is the best way to make a boat go faster, if not, then a Blower would help, but then the Rotating Assembly takes a beating
53 isn't all that fast. Were you Way Over trimmed?
If you are only dropping 2mph with 7 additional People, You are doing well
If you are trying for more Speed, fewer Prop Blades will help. Also leave the Wife, Kids and the Mother-in-Law, especially the Mother-in-Law ashore. Girl Friends and...
