Engine mounts

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Patriciamarie
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Engine mounts

Post by Patriciamarie » Tue Jan 22, 2019 12:12 am

Any advice on adjusting both engines , both shafts are real close to the through hull tubes.
Their is no vibration at all and I'm concerned about making a bigger problem. I've read flange to flange is 1 to .003 . In or out of the water.
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The Dog House
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Re: Engine mounts

Post by The Dog House » Tue Jan 22, 2019 6:32 am

If the shafts are not touching the shaft log I wouldn't change anything. My shaft is closer to one side than the other. The alignment of the strut and the engine/transmission is what's important. If the shaft is not touching the shaft log the alignment of the shaft log and the shaft is not important.
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prowlersfish
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Re: Engine mounts

Post by prowlersfish » Tue Jan 22, 2019 6:04 pm

I basically agree with Dog house . If its not hitting and the flange alignment is ok no worries .just make sure all your mounts are good . while you can do alignment on land ,it must be rechecked in the water . You likely will find the shaft sitting differently when over board
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P-Dogg
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Re: Engine mounts

Post by P-Dogg » Wed Jan 23, 2019 12:19 pm

prowlersfish wrote:
Tue Jan 22, 2019 6:04 pm
while you can do alignment on land ,it must be rechecked in the water . You likely will find the shaft sitting differently when over board
My mechanic waits three days to do final alignment after refloating.
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Patriciamarie
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Re: Engine mounts

Post by Patriciamarie » Fri Feb 08, 2019 10:13 pm

Hey thanks.

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Big D
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Re: Engine mounts

Post by Big D » Mon Feb 18, 2019 10:49 am

Here's my 2 cents FWIW;
While being off center a bit is okay, that seems too extreme for my liking and I'd be recommending to have it remedied. Having said that, we're looking at the results with the vessel out of the water which can skew the actual position if the boat isn't blocked with care. There are a lot of variables for which we don't have information on here such as model, HP, shaft diameter, running conditions, etc. but in any case there is very little or no room for deflection which can happen under the right conditions assuming the position of the shaft is the same when the vessel is in the water. You can get that much deflection in hull movement through rough seas or on plane through someone's wake. If it's real close to the tube, you can probably hit it intentionally just through engine torque. If all you do is putter along from A to B then maybe it's not that much of a concern but could become an issue at the most inopportune time such as being caught in a storm when you're praying there are no power plant of running gear failures.

If you're sure there's no vibration then it would seem the engine was aligned to accommodate a misaligned strut or one that was tweaked/bent as the result of a previous impact enough to throw off the shaft alignment through the tube. My other concern would be whether your shaft log and hose are sitting square to the shaft and tube. Check to see if the shaft is centered in the log or if it sits off to one side a bit, and look at the shaft on the outside and see if there are any signs of it ever having rubbed against the tube.

Based strictly on observations from the pictures and considering some assumptions that can only be confirmed on physical inspection, I suspect the fix here (if it were me) would be to uncouple the shaft and send it to a prop shop to ensure it's not bent (should be a free service). While you're at it, give them the prop too. In simplified terms; once you're sure the shaft is straight, set it into the strut and tube and center the shaft in the tube with shims to hold it in place. If it's difficult to center it and you can't turn it in that position then the strut needs to be removed, shimmed, and re-bedded in the correct position so the shaft rests with ease in the center of the tube and turns freely in the strut without pinching the strut bearing anywhere. Then align the engine so the transmission flange to shaft coupler gap is no more than .003" out and that the gap is even at every point between the two mating surfaces. I usually get this close on land so I know everything is set properly outside. Then splash and wait 24 hours prior to doing the final alignment.

One final note; I've ran into this condition on several occasions where upon close inspection it became obvious that engines were aligned in this manner to make up for improper engine placement as an easy way out. If one runs out of adjustment on the engine mount to move the engine up, one can shim under the mount. It's a whole new ball game when you run out of room on the mount to move the engine lower or to one side. Rather than doing the right thing, some will just cheap out/time out and align to any position that will achieve the alignment spec even if it means throwing off shaft alignment through the strut and tube.
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prowlersfish
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Re: Engine mounts

Post by prowlersfish » Mon Feb 18, 2019 6:03 pm

Good advice Big D . I had though about this and wonder if the engine mount may have gotten weak and are sitting lower ?
TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat :D
2009 TROJAN RENDEZVOUS
Port Kinsale 2010 & 2011. Solomons get together 2011.

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