How do you know if your engine is out of alignment? This is the question that covers quite a bit of ground. There are many factors to deal with. Some of the areas that must be determined before you align the engine are:

a. The shaft should be pulled and checked to make sure it's perfectly straight.

b. The strut bearing must be in good condition.

c. The propeller shaft coupling must be true.

d. The strut itself must be straight.

What are the symptoms of misalignment?

a. Vibration - mostly at high R.P.M. can feel like you have a bent propeller. It's always good to send the propeller out to a repair shop if you have a vibration. Also, a bent shaft can cause vibrations.

b. Prop is hard to turn when boat is out of water and in neutral.

c. Shaft wiggles when in gear at idle at the shaft log.

d. When the prop shaft is disconnected from transmission it is hard to get it back on the transmission.

As you can see, there are many variables when it comes to this; so below we are going to list the procedures that are necessary to do a comprehensive engine alignment.

1. Remove propeller, send it to a propeller repair shop to be checked and repaired. NOTE: never use a hammer to remove a prop. Use a prop puller.

2. Remove safety wire on prop coupling and back out set screws or on some Century boats, drive out the "roll pin" using a punch.

3. Hook a slide hammer to the threads on the end of the prop shaft using a coupler nut and slide hammer the shaft out of the prop shaft coupler flange that is still bolted to the transmission.

4. Take the shaft to a machine shop and have them check the shaft for straightness, using a dial indicator. It must be within .006 over the full length of the shaft.

5. Check the wear areas of the shaft at the strut and the shaft log. Make sure that the wear patterns are within .010.

6. Check the inside diameter of the strut bearing for wear. You can use the shaft for this. Stick the shaft in the strut, just part way, and not in a wear area. If you can shake it side to side or up and down replace the strut bearing. The strut bearing is a brass sleeve that they vulcanize a very hard rubber sleeve to, which has a series of flats on it that the shaft rides on. It is lubricated by water in between the flats. If your boat is in a very sandy area, the strut bearing will wear out quite quickly (three or so years). To replace the strut bearing, and if you do not have a press, take a hack saw, disconnect the blade, pass it through the strut and reconnect it to the saw handle. Now very carefully saw through the rubber and through the brass sleeve without sawing through the strut itself. You may want to check this often. Then take a screwdriver and pry up a corner of the sawed strut bearing and then peel it up full length. Now take a punch and drive it out. NOTE: On some Century models the strut bearing is held in with set screws. These must be removed. Now clean out the inside diameter of the strut with sandpaper or emery cloth. Measure the inside diameter and the length and call us at the Wooden Boat Shop or your local marine dealer that works on straight inboards and order the strut bearing. Now, installing the strut bearing is very easy if you have a press but if you don't, take a 15-inch piece of threaded rod, four flat washers and two nuts. Find out which side of the new strut bearing goes into the strut the farthest. Take the threaded rod, put on the nut and double flat washers and slide it through the strut and the new strut bearing, lubricate the strut and bearing with a product like STP. Run the washers and the nut down until it makes contact with the new bearing. Be careful to make sure the new strut bearing is in alignment of the strut and start tightening the nut. Do not kink the bearing as you tighten it because it will go into the strut. When flush, you are done. This can be done on the boat. Now we have a prepared prop, straight shaft and new strut bearing.

7. Lubricate the shaft with any good anti-friction oil and slide the shaft in through the shaft log and into the shaft coupler. Make sure you line up the key ways and key, then run the shaft in using the slide hammer again. Use a flashlight to line up the "D-dents" in the shaft for the set screws or the roll pin. After tightening the set screws, safety wire them again so they can not back out.

8. Now we have everything ready to align the engine. To align the engine correctly the boat must be in the water.

A. Disconnect prop shaft flange from the transmission.

B. Pull the flanges together, use a feeler gauge and measure every 120 degrees. You are looking for the same amount of friction when you pull the feeler gauge out in all three places around the flange. If it’s tight at the bottom and loose at the top, then the front of the engine must come up. Now, some boats like Chris Craft have wedges that are used to adjust the engine heights.

C. Loosen the bolt (log screw). Take the two wood screws out of the wedge then, using a hammer you can go up and down. Also, if you look up from the bottom at the areas where the shaft passes through the hull and if the shaft is rubbing on one side or the other, you may have to straighten or replace the strut because it is bent. Now, other models have adjusted mounts on the engine and they can be adjusted by turning the "jack bolts" at the mount up or down. Greymarine V-8's, Crusader and other manufacturers have those. Just loosen the top nut, adjust with bottom nut and retighten the top nut when finished. On late model engines you can adjust side to side and up and down (Crusader, Marine Power, PMC). After you have the engine in line tighten everything. On models with wedges and if they are not drilled for a screw, run a wood screw on both ends of the wedge to eliminate any chance of movement. If they are drilled, run a screw in the hole, tighten the center bolt and then give it a test run.

If you want to tackle this job and need assistance just give me a call at the Wooden Boat Shop 513/941-7281.If you need a strut bearing, shaft, prop repair, shaft log packing, shaft log hose, coupler flanges, castle nuts etc. just give us a call. I am happy to serve our readers in every way I can.