Engine is a 1987 Mercruiser 260/V8 - serial number 0B651656
Drive is an Alpha One Gen 1 - serial number 0B612075
Boat is a 1987 Power Play XLT-185 (19 ft closed bow runabout)
I splashed my project this past weekend - man what a blast. This is my first boat and it felt great out on the water. When running it, I was able to get up to 4,000 RPM at WOT and GPS indicated 50 mph. I'm running a 21 pitch 3 blade cleaver prop (I'm told this is one of the props that was originally sold on this boat when new). Based on some notes I had taken from somewhere on this forum, I think I should be closer to 4,600 - 4,800 RPM at WOT, correct?
Thinking about what may be the cause made me wonder if I have my base ignition timing set correct. My engine has the TB IV ignition system. Are there different TB IV systems that require different base timing? Unfortunately someone who owned the boat before me spray painted over the label on top of the TB IV module, so I can't see any of the part numbers or other data that may be on there. When timing the engine before going out for the water test, we set the idle to between 650-700 rpm in neutral, put the timing light on the #1 spark plug lead, and set the timing to 8 degrees BTDC.
Other things I'm thinking may be the cause are old plug wires (I have new plugs, distributor cap, and distributor sensor) or maybe some adjustment on the carb or throttle linkage. Or maybe this prop is just too much pitch? 50 mph is plenty fast for what I need the boat to do, but I'm just wanting to make sure I'm not hurting something by not being able to get to the ~4,700 rpm range. Appreciate all constructive input.
Drive is an Alpha One Gen 1 - serial number 0B612075
Boat is a 1987 Power Play XLT-185 (19 ft closed bow runabout)
I splashed my project this past weekend - man what a blast. This is my first boat and it felt great out on the water. When running it, I was able to get up to 4,000 RPM at WOT and GPS indicated 50 mph. I'm running a 21 pitch 3 blade cleaver prop (I'm told this is one of the props that was originally sold on this boat when new). Based on some notes I had taken from somewhere on this forum, I think I should be closer to 4,600 - 4,800 RPM at WOT, correct?
Thinking about what may be the cause made me wonder if I have my base ignition timing set correct. My engine has the TB IV ignition system. Are there different TB IV systems that require different base timing? Unfortunately someone who owned the boat before me spray painted over the label on top of the TB IV module, so I can't see any of the part numbers or other data that may be on there. When timing the engine before going out for the water test, we set the idle to between 650-700 rpm in neutral, put the timing light on the #1 spark plug lead, and set the timing to 8 degrees BTDC.
Other things I'm thinking may be the cause are old plug wires (I have new plugs, distributor cap, and distributor sensor) or maybe some adjustment on the carb or throttle linkage. Or maybe this prop is just too much pitch? 50 mph is plenty fast for what I need the boat to do, but I'm just wanting to make sure I'm not hurting something by not being able to get to the ~4,700 rpm range. Appreciate all constructive input.
