mperret
05-31-2006, 02:12 PM
:?: I need to replace my old MR outdrive, and I am getting conflicting advice about the correct gear ratio and prop pitch to use. I would appreciate some help. The existing drive (1985 MR) is 1.50, I believe.
Here are the boat particulars:
1982 Chris Craft 264 Scorpion (Express Cruiser)
LOA 26'5" Beam 8'0" Draft 2'11" Displacement 4,600 lb.
MerCruise 260 HP 350 CID / 5.7 liter V8 Carburetor/Electronic Ignition
Engine Model MCM260 rated at Max 4200 - 4600 RPM (WOT)
Existing prop is three-blade ss 14" diameter with 17" pitch
The boat will normally carry two adults and supplies for one week or less. We intend to use the boat for cruising river / canal waterways around Lake Ontario, so priorities are low speed handling and economy. Some cruising on plane will obviously be required, and efficiency and economy are issues with fuel prices as they are, but max speed is not important.
One source says the old 1.50 drives should be replaced with a 1.47 ratio, and another says the V8 should have a ratio around 1.87. I would appreciate any advice about gear ratios and props that will point me in the right direction. Thanks.
Here are the boat particulars:
1982 Chris Craft 264 Scorpion (Express Cruiser)
LOA 26'5" Beam 8'0" Draft 2'11" Displacement 4,600 lb.
MerCruise 260 HP 350 CID / 5.7 liter V8 Carburetor/Electronic Ignition
Engine Model MCM260 rated at Max 4200 - 4600 RPM (WOT)
Existing prop is three-blade ss 14" diameter with 17" pitch
The boat will normally carry two adults and supplies for one week or less. We intend to use the boat for cruising river / canal waterways around Lake Ontario, so priorities are low speed handling and economy. Some cruising on plane will obviously be required, and efficiency and economy are issues with fuel prices as they are, but max speed is not important.
One source says the old 1.50 drives should be replaced with a 1.47 ratio, and another says the V8 should have a ratio around 1.87. I would appreciate any advice about gear ratios and props that will point me in the right direction. Thanks.