If anyone can give me some information on how to move the shaft a little to the port side of the boat I would really appreciate it. The shaft is knocking at higher revolutions and I noticed that it is too far to the stbd side. In order to move it an inch to the port, which direction will I move the engine?
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I had a similar problem with my old 1980 H30. The shaft was not knocking but was rubbing on the shaft log and eventually wore it thin and then the shaft log broke. The yard had to re-align my shaft by moving the prop strut around so that the shaft could be more or less centered in the shaft log. They then aligned the engine to the new shaft position. Before going through all of that, you may want to check to see if your shaft is bent.
To explain further...
Raising and lowering the four mounts effectively realigns the shaft. The procedure is found in the Archives on this website. Basically you remove the bolts from the shaft to the engine and adjust the mounts so there is 1/1000th of an inch clearance all the way around the inside of the two circles. Then you reattach the bolts. Service yards use laser lights to accelerate the process.
Raising and lowering the four mounts effectively realigns the shaft. The procedure is found in the Archives on this website. Basically you remove the bolts from the shaft to the engine and adjust the mounts so there is 1/1000th of an inch clearance all the way around the inside of the two circles. Then you reattach the bolts. Service yards use laser lights to accelerate the process.
Ted, I went through this earlier this year.
I have a 280 but the process should be the same. You say you want to adjust your shaft a bit to Port. My suggestion is to start from scratch. Others here have alluded to certain resolutions but were pretty general. My only assumption is that the prop strut is aligned properly and that your cutlass (sp?) bearing is OK. The first thing to do is to center your shaft in the shaft log. Disconnect the bolts between the transmission flange and the shaft flange. Move the shaft flange up/down/P/S to find its center. Once you are confident where that is, block the shaft to hold it there. Next, position/align the transmission flange to the shaft flange. Use the mount bolts to adjust the engine/trans flange up or down and the bolts for the engine mount base for P & S. You'll just have to observe based on position of the bases to see if move the forward mounts or rear mounts horizontally is your best choice. Use .02 mm (Yanmar manual)or .001" as tolerance between the shaft flange and trans flange. rotate your shaft flange 90* and check again. I can help in more detail if you contact me via email. If during the process of rotating the shaft flange 90-180* and rechecking you find that a gap changes oreintation, you may have a bent shaft.
I have a 280 but the process should be the same. You say you want to adjust your shaft a bit to Port. My suggestion is to start from scratch. Others here have alluded to certain resolutions but were pretty general. My only assumption is that the prop strut is aligned properly and that your cutlass (sp?) bearing is OK. The first thing to do is to center your shaft in the shaft log. Disconnect the bolts between the transmission flange and the shaft flange. Move the shaft flange up/down/P/S to find its center. Once you are confident where that is, block the shaft to hold it there. Next, position/align the transmission flange to the shaft flange. Use the mount bolts to adjust the engine/trans flange up or down and the bolts for the engine mount base for P & S. You'll just have to observe based on position of the bases to see if move the forward mounts or rear mounts horizontally is your best choice. Use .02 mm (Yanmar manual)or .001" as tolerance between the shaft flange and trans flange. rotate your shaft flange 90* and check again. I can help in more detail if you contact me via email. If during the process of rotating the shaft flange 90-180* and rechecking you find that a gap changes oreintation, you may have a bent shaft.
sounds like a bent shaft. or bad mount
this sounds like the shaft if bent or is bending under load. I agree a complete alignment isin order but i dont think you want to move anything an inch. As suggested disconnect the coupling and so on. you may also have a bad cutlass bearing, causing things to get out of line. but if its not rubbing at slow speed i would pull the shaft and have it checked while you at it. If the cutlass is not in line with the safe tube it would wear out pretty quick so from your description, i would haul it check the cutlass and shaft for straigness then install the shaft and realing the engine.
this sounds like the shaft if bent or is bending under load. I agree a complete alignment isin order but i dont think you want to move anything an inch. As suggested disconnect the coupling and so on. you may also have a bad cutlass bearing, causing things to get out of line. but if its not rubbing at slow speed i would pull the shaft and have it checked while you at it. If the cutlass is not in line with the safe tube it would wear out pretty quick so from your description, i would haul it check the cutlass and shaft for straigness then install the shaft and realing the engine.
I forgot one piece of info!!
Thanks for all the advice. By the way the boat is a 78 I forgot to mention that I am now in the water in Florida. I know that the shaft was out of alignment a while ago and in order to lift the shaft I had to lower th front engine mounts. So now my question is:which way do I move the engine in order to move the shaft towards the port side of the boat because from inspection I can see that it is rubbing on the starboard side of the opening in the hull
Thanks for all the advice. By the way the boat is a 78 I forgot to mention that I am now in the water in Florida. I know that the shaft was out of alignment a while ago and in order to lift the shaft I had to lower th front engine mounts. So now my question is:which way do I move the engine in order to move the shaft towards the port side of the boat because from inspection I can see that it is rubbing on the starboard side of the opening in the hull
My mounts can move side to side
After reading the various comments last week I had a good look at the mounts on my HC37's 3QM30 and noticed (for the first time) that the holes in the engine mounts for the bolts that go into the stringer (bed) are slotted and would allow side to side movement. Together with the up and down adjustment in the mounts themselves, that would allow linear side to side, linear up and down, and angular adjustment in both the horizontal and vertical planes. It may therefore be that if the shaft is off to one side in the shaft log that can be adjusted out. John Brecher
After reading the various comments last week I had a good look at the mounts on my HC37's 3QM30 and noticed (for the first time) that the holes in the engine mounts for the bolts that go into the stringer (bed) are slotted and would allow side to side movement. Together with the up and down adjustment in the mounts themselves, that would allow linear side to side, linear up and down, and angular adjustment in both the horizontal and vertical planes. It may therefore be that if the shaft is off to one side in the shaft log that can be adjusted out. John Brecher
Larger picture
When playing with engine alignment you have to look at the entire system; engine, coupling, shaft, log, cutless, mounts. You dropped the FRONT of the engine to raise the shaft. Doing this made the REAR engine mounts a PIVOT point. This lifted the coupling, also lifting the entire shaft along it's length. In theory it would have the shaft pressing UP at the cutless. At best this is not a good situation because that stress is located at the output shaft and coupling. Simply put, you have caused a gap at the TOP of the coupling where the two coupling faces meet. To raise the shaft you must raise the entire engine, turning up the nuts on all four mounts. This will keep the trans output shaft and prop shaft in a perfect straight line, which is what you are attempting to do. As mentioned elsewhere you do essentialy the same for side to side movement except this is done by swinging the mounts on their slots. Keep in mind you want to keep the load the same on all four mounts. Remember, the engine and shaft as a unit must line up through the cutless and log. To accomplish this correctly you must remove all four coupling bolts. The shaft and it's coupling face are now free to move about. You need to keep them lightly in contact whole you use a feeler around the circumference. Push the feeler in to the joint as you squeeze together. Anything under .003" (three thousandths of an inch)is OK. To be certain, shake the engine on it's mounts and measure again, and again. When you get no change you're good. A flex coupling here is good because it makes the alignment of the coupling faces a lot less critical and absorbs a lot of vibration. To really do this right you would align the STRUT and cutless to the log, and there after the engine/shaft unit to them. The strut on my 1983 33 was off a good amount, which I had the opportunity to correct when I replaced the strut. But that's a whole different post which I think you'll be able to find in the archives. A side note here. Do not lean on the engine as you check the coupling gap with the feeler. Your weight will move the engine on it's mounts obscuring the true measurement. Do not ask how I learned this.
When playing with engine alignment you have to look at the entire system; engine, coupling, shaft, log, cutless, mounts. You dropped the FRONT of the engine to raise the shaft. Doing this made the REAR engine mounts a PIVOT point. This lifted the coupling, also lifting the entire shaft along it's length. In theory it would have the shaft pressing UP at the cutless. At best this is not a good situation because that stress is located at the output shaft and coupling. Simply put, you have caused a gap at the TOP of the coupling where the two coupling faces meet. To raise the shaft you must raise the entire engine, turning up the nuts on all four mounts. This will keep the trans output shaft and prop shaft in a perfect straight line, which is what you are attempting to do. As mentioned elsewhere you do essentialy the same for side to side movement except this is done by swinging the mounts on their slots. Keep in mind you want to keep the load the same on all four mounts. Remember, the engine and shaft as a unit must line up through the cutless and log. To accomplish this correctly you must remove all four coupling bolts. The shaft and it's coupling face are now free to move about. You need to keep them lightly in contact whole you use a feeler around the circumference. Push the feeler in to the joint as you squeeze together. Anything under .003" (three thousandths of an inch)is OK. To be certain, shake the engine on it's mounts and measure again, and again. When you get no change you're good. A flex coupling here is good because it makes the alignment of the coupling faces a lot less critical and absorbs a lot of vibration. To really do this right you would align the STRUT and cutless to the log, and there after the engine/shaft unit to them. The strut on my 1983 33 was off a good amount, which I had the opportunity to correct when I replaced the strut. But that's a whole different post which I think you'll be able to find in the archives. A side note here. Do not lean on the engine as you check the coupling gap with the feeler. Your weight will move the engine on it's mounts obscuring the true measurement. Do not ask how I learned this.
Thanks so much !
Thanks for all your help. I did indeed undo all the mounting screws and managed to move the engine over just enough to seemingly fix the problem. No rubbing now and no banging. Hope this is now the proper alignment
Thanks for all your help. I did indeed undo all the mounting screws and managed to move the engine over just enough to seemingly fix the problem. No rubbing now and no banging. Hope this is now the proper alignment
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