Al writes: >I'm not sure if all boats (I only know mine) have a lip on the transmission f>lange which mates to the shaft coupling. This looks to be a pretty tight fit >and takes the weight of the shaft. With the shaft coupling sitting on this >lip it is a relatively easy thing to run the feeler gauges between the mating >surfaces. Since it doesn't require any buggylugging to fit or tighten It may be a common misconception that because the lip on the couplings line up, that the engine is in the proper plane up and down, and that the shaft deflection has been accounted for. In a short shaft this may be a close assumption. Different metals have different deflections, and what would be proper for brass, might not be proper for Stanless or Monel. Please envision that the shaft deflects one inch (I have seen this in a shaft), so the engine is placed so that the lips on the couplings engage and the engine is then aligned to this deflection--in fact the shaft is out of true and as it turns at normal operating RPM, it causes stress on the tranny seals and output shaft bearings, as well as on the shaft log and Cutlass bearing. This is why I suggest that a deflection curve (spring scale does this) or lasser be used to properly oosition the center of the tranny coupling (output shaft) in the center of the shaft alley and true with all bearings. As to alignment--remember that the rear engine mounts are forward of the output shaft coupling, so that they move on a fulcrum up and down (opposite of what the front mounts do. If you raise the front of the engine, you will narrow the space at the top of the coupling, and widden it at the bottom--however you must also take up a small amount in the rear mounts, so that the output shaft center remains the same. Thus the idea of keeping the spring scale in place while aligning the engine. Arlid suggested that one might use the lasser to sight the shaft straightness. Make a model, proportionate to your engine and mounts. Glue popcicle sticks across to be the enginehangers, and experiment with the amount and direction as you adust the mounts. In Al's case there was an intermediate bearing on only a six foot shaft (very short shaft, unless there was a V drive). I probably would have replaced that bearing since the designer had felt that there was need. These types of bearins are often roller bearings, with grease fittings--actually a cup is often more handy than using a zerk fitting, since the grease cup can be mounted remotely. All of this said--most folks who do alignments will not go to all of this trouble--but I have a neighbor who has blown two transmissions in two years--probably due to this misalignmnet. So what is cheaper an extra hour or two of labor, or two Trannys? Regards, Bob Austin

<<All of this said--most folks who do alignments will not go to all of this trouble--but I have a neighbor who has blown two transmissions in two years--probably due to this misalignmnet. So what is cheaper an extra hour or two of labor, or two Trannys?>> Apparently, the boatbuilders and engine installers don't even pay proper attention to engine alignment. Last Fall at TFest Solomons, I aligned the engine on an almost new Nordic Tug. The engine was so far out of line with the shaft, that there wasn't enough adjustment range available in the engine mounts to correct it. We had to drill new holes for the engine mount bolts to get the alignment correct. This winter, I was asked to align the two new Yanmar 275 HP engines a friend had recently had installed by a local yard in Stuart, FL. The yard had fabricated mount "risers" to make up for the different mounting heights of the Yanmars and the old Perkins engines they replaced. Again, after pushing one engine all the way against the stops to port, the shaft would not line up by about 1/8". The risers had to be removed, and their mounting holes elongated to allow proper alignment. Alignment is not easy, but it is simple. It usually requires a lot of fiddly adjusting to get it right, and occasionally some brute force to get the beast moved to the right position, but it's not rocket science. Watch your mechanic the next time you have the job done, and then try it yourself. ===== Mark Richter, M.E., aboard M/V Winnie the Pooh, custom Morgan 46 Pilothouse Efficiency Trawler. "Mark's Mobile Marine" electrical systems repair & consulting. Homeport Stuart, FL __________________________________________________ Do You Yahoo!? Yahoo! Auctions - buy the things you want at great prices http://auctions.yahoo.com/