Strut and or Shaft Issues

[sjp]

I am still trying to figure out my boat. In-boards are completely new to me, and I am now trying to figure out if I have any drive shaft/strut issues.

This is an 89 Supra Mariah with a reverse rotation PCM 351. I already had to replace the rudder, and there was evidence that the boat had been grounded. This is part of the reason why I am nervous about the driveshaft and strut. I should also add that the boat was leaking more water out the shaft than it should, and it might have some vibration, although I am new to inboards so I don’t know what is normal.

So I crawled under the boat and took a closer look at the shaft and strut. The first thing I noticed is that the shaft does not appear to be centered in the strut. There is a larger gap on the bottom left, and a larger gap on the top right. I don’t have any idea if this is normal. If it is not normal, how can I tell if it is just a bad bushing, or if the strut and or shaft might be bent.

The second thing I noticed is that the shaft is not centered where it comes out of the boat. Does that look normal?

One more thing--- it might be my imagination, but I think where the shaft come out of the boat looks different then it did before. Like there might be something missing where the shaft comes out of the boat—that was there before. I have only taken this boat to the lake twice, so this might be my imagination. I don’t have any “before” pictures here. Does it look like I am missing something?

So, how can I tell if there is a problem with my shaft and/or strut? How can I tell if the stut or shaft is bent?

Jared

[wesgardner]

Hey sjp,

Here's a list of to do's

Check for shaft straightness
Replace cutlass bearing
Repack stuffing box
Align shaft
Have prop checked (this can cause vibration and is very common)

Let's start with making sure the components are OK - the shaft needs to be STRAIGHT, the only way I know to tell is PULL IT - I used to roll ours on a very flat surface - like you'd roll a pool cue to see if it was straight, I'm sure there are machine-shop style tests for this...this leads me to a point - the strut/shaft is OFFSET from the rudder to allow pulling the shaft without needing to drop the rudder. Where the shaft enters the hull (the stern tube) this DOES NOT need to have equal clearance so from the pics, this part looks OK. Your cutlass bearing - that's the rubber splined thing that's held in the strut by that allan screw needs to be replaced (see the cracking and general degrading of the rubber?) - We used to use an old piece of shaft from a slightly larger boat to drive the old one out and replace with new - another method - once the shaft has been pulled, use a hack saw to carefully cut through the realtively soft bronze case of the cutlass bearing and collapse it in on itself - maybe the local shop can/should do this for you?

From the pics, it looks like all is well as far as "missing" parts

Once shaft has been "blessed", reinstall it - you then need to repack your stuffing box (there are a bunch of articles floating around regarding "how to" for this so I won't recreate the wheel, you then need to align the motor to the shaft - articles abound on this as well.

A note: once you separate the shaft coupling, you'll get a general idea of how bad (if any) your motor is out of alignment or if the strut is bent - the entire concept of aligning the motor to the shaft might be new to you? There are tolerances you check with a feeler gauge (can't recall exact numbers but will be discussed in alignment articles) If the strut is bent, this will cause the shaft to "spring" way over to one side of the coupling...

Be forwarned - getting the shaft out of older couplings can be a chore in and of itself - I was able to borrow a puller from AutoZone or Advanced Auto that worked real well - sometimes heat is necessary...I've seen folks separate the coupling and using extended bolts, compress a short bolt inside the coupling forcing the shaft out (hard to explain without being there) - maybe someone has pics or a better explanation...

Hope this helps

Wes