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a preliminary guide . Make sure the top of the dam is approx. 1" above the top of the stern tube. Also make sure that there is at least 3" of stern tube exposed forward of the dam. This is to provide clamping surface for the shaft seal. Add a piece of plywood to close off the top of the slot. When you have completed the dam, hot melt glue it to the hull and stern tube. Make sure there are no holes for the resin to seep through. Lay a bead of hot melt glue around the stern tube in the prop aperture to prevent resin leakage there also. DO NOT disturb the plywood or the stern tube after this point! Do not touch the engine! Do not do anything that will alter the alignment of the shaft! (Screw Top) The next step is to pour enough fiberglass in the resulting cavity (aft of the dam) to permanently set the stern tube in place. Do the pour in several stages because if you fill the entire cavity at once you will start a fire when it heats up (Screw Top). I would fill the cavity in five or six pours to be safe. Make sure you completely cover the stern tube by at least an inch. This may take several days. A level boat at this point will ensure a level pour when you are done. Make sure you get a high fiberglass to resin ratio because a resin rich mixture will crack and will not provide proper support for the stern tube. 50-50 ratio would be nice. Use a stick to force the mixture into all areas. No voids are allowed. After the fiberglass has set for a couple days, remove the bearings and prop shaft.
At the prop aperture, trim off the extra length of stern tube and make it flush with the hull. Drill two 1/8" holes at 3:00 and 9:00 about 2" inches from the end of the stern tube. Install a shaft bearing in the aft end of the stern tube and, using the hole locations you just drilled, gently drill a very small mark on the bearing's bronze housing. Remove the bearing and drill a 5/16" diameter hole no more than halfway into the bearing's bronze housing. These dimples will receive 1/4"-20 set screws that prevent the bearing from spinning out. Mark on the outside of the housing where the holes are located to more easily align the dimples. Drill and tap the two holes (at 3:00 & 9 :00) in the hull (prop aperture) to accept 1/4"-20 threads. The correct drill size is given on the tap shaft. You may need two taps for this job because fiberglass is pretty hard on taps. Install the shaft bearing and install two 1/4"-20 stainless steel set screws in each hole. The second set screw will act as a locking device. Do not over tighten! Take the prop and prop shaft (and zinc if it's the prop nut type) to a marine machine shop. Tell them you don't know what the length is yet but you wish to have the shaft machined to accept the prop. It will most likely be a standard Morse taper with a keyway. After the shaft is machined, reinstall the rudder and screws. Tie it hard to one side. Reinstall the prop/prop shaft assembly through the stern tube/shaft bearing and into the coupler(s). Make sure the zinc prop nut is installed. Swinging the rudder back and forth, progressively cut off the shaft on the coupler end until it clears the rudder. Don't cut off too much! If you do not have prop nut zinc make sure you leave enough room between the prop and the hull for the collar zinc. Important! Remove the prop. Take the cut-to-length prop shaft and the shaft coupler back the machine shop. Tell them you want them to true the shaft, square the coupler to the shaft and machine a keyway and drill dimples where the set screws come in from the coupler. Ask them for a couple extra keyways.
When the shaft is finished, reinstall the prop shaft assembly and do the final engine coupler to prop coupler alignment. The procedure is in the owner's manual. It is a lot easier if you install another shaft bearing in the forward part of the stern tube to support the shaft. It is more of a hassle but you'll get a more accurate reading. Remove the bearing when you're through and keep it as a spare. Install the shaft seal (follow manufacturer's instructions), propeller (using the keyway), zinc and shaft bearing (using the set screws).
INSTALLING SUPPORT HARDWARE
The fuel filter must not be installed higher than the injector! (Another Screw Top Tale) Make sure you can remove the fuel filter cover to change filters. If you put a 5/16" squeeze bulb (used in outboard engines) in the fuel supply line you can pressurize the system a lot quicker than relying on the manually operated engine mounted fuel pump primer. If a siphon effect is created in the line you should not have to install an electric fuel pump like the factory does. Remove the bulb after the siphon effect is established. The exhaust thru-hull fitting is installed on the transom. I would place it a little higher than where the factory does because it has a tendency to submerge while motoring. Make sure there is a large loop going all the way to the top of the transom to break any siphon effect. A U-shaped
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