Re: 1994 Century 2000 with new 150 honda
Your question is typical and one that can't be answered because you provided no "current" performance data to work with. First, with the engine tilted down, where is the AV plate in relation to the keel. If it's below the keel, raise the engine mounting at least one hole. The AV plate needs to be flush to at least an inch or two above the keel. It gets more of the lower unit out of the water thus reducing drag and increasing performance. Then we need to know the diameter, pitch, type (manufacturer) and style (3 or 4 blade, aluminum or stainless) of the prop you have now. Check the barrel of the prop or the hub (behind the nut) for these numbers. Then make some wide open throttle runs with an average load and note speed and engine rpm. "About" is not an acceptable number. These runs need to be made over a distance that you know the boat is maxed out. Vary the trim to obtain maximum speed. GPS is the preferred speed measurement device. The prop you need is one that allows the engine to run in the manufacturers recommended WOT band (usually 5500 rpm give or take a little). If the engine is running faster than that by just a hundred or two rpm, the prop is correct. If it runs way over the limit, you need to increase pitch (1-inch=about 200 rpm). If the engine does not reach that rpm you need to decrease pitch to get the rpm up as you are "lugging" the engine and they don't like that. Again, 1-inch of pitch decrease, raises engine rpm by about 200 rpm. The important thing is to research props carefully as a 19P prop from vendor "A" will not perform the same as a 19P prop from vendor "B". Go to a prop shop -- they will let you try various styles of props. If you guessed that prop selection is a "crap-shoot" you'd be correct. There is no such thing as a "standard" prop for any given boat/load/engine combination. Dealers get close due to trial and error, but unless you do some testing, you really can't predict what you need. Finally, unless the existing prop is "way wrong" don't look for a magical 10 MPH increase in speed. 3-5 maybe with proper engine setup and an efficient prop. Better hole shot is certainly achievable with a different prop. Also consider Smart Tabs (automatic trim tabs) if you have a very stern-heavy boat. Be aware that by raising engine height you can go so high that the water inlet ports on the engine can no longer suck water so installing a water pressure gauge is highly recommened. It is a good gauge to add anyway as it tells you how good or bad the water pump is.
