Transmission to prop shaft coupler bolts loose

[pbyrne]

While trying to figure out where the coolant leak might be coming from, I noticed some of the bolts on the transmission to prop shaft coupler are loose and spin easily.  I think one of the nuts was actually able to be spun off.

I don't think this is normal!

What is the correct tightness or torque, and shouldn't these nuts be Loctite'd (i.e. low strength purple 222 so they can be removed if needed) to prevent this situation?

In the photo you can see the gap where the arrow points.

Thoughts?

[KWKloeber]

Are those nylocks?  Bolts look too short
Is that a lock washer under the head or am I seeing something else?

[Jim Hardesty]

don't think this is normal!

No it's not.  I see that you have a flex coupler.  I think the torque and locking specs should come from the flex coupling manufacturer.  If mine I'd take the coupling apart and inspect/replace nuts and bolts with same grade after you find the coupling manufacturer specifications.
If nothing else get all the coupling nuts/bolts as tight as you can.  It's not like you can get a breaker bar on them, probably just standard wrenches.  And check them often at first, then at least yearly. 
Looks like you found a problem just before it became serious.   
Jim

[scgunner]

pbyrne,

For the time being I'd tighten everything up. It doesn't look like it was assembled correctly, so the next thing I'd do is get a copy of the installation directions and see what's recommended. There are a couple of things that don't look right. At the head of the bolt I can't tell if those are lock washers or bushing washers(this makes more sense). Next the bolts aren't long enough to capture the nyloc, which defeats the purpose, if you can't use longer bolts due to clearance issues you'd be better off using a standard bolt with a lock washer.

[pbyrne]

Do you think this is a standard installed part of a 2000 34 MKII?

I'm getting the impression that it's a bit of an unknown...

don't think this is normal!

No it's not.  I see that you have a flex coupler.  I think the torque and locking specs should come from the flex coupling manufacturer.  If mine I'd take the coupling apart and inspect/replace nuts and bolts with same grade after you find the coupling manufacturer specifications.
If nothing else get all the coupling nuts/bolts as tight as you can.  It's not like you can get a breaker bar on them, probably just standard wrenches.  And check them often at first, then at least yearly. 
Looks like you found a problem just before it became serious.   
Jim

[pbyrne]

Jim,

What does your boat look like?  We have approximately the same age and model.

Is this what you have installed; is it OEM?

don't think this is normal!

No it's not.  I see that you have a flex coupler.  I think the torque and locking specs should come from the flex coupling manufacturer.  If mine I'd take the coupling apart and inspect/replace nuts and bolts with same grade after you find the coupling manufacturer specifications.
If nothing else get all the coupling nuts/bolts as tight as you can.  It's not like you can get a breaker bar on them, probably just standard wrenches.  And check them often at first, then at least yearly. 
Looks like you found a problem just before it became serious.   
Jim

[Jim Hardesty]

What does your boat look like?  We have approximately the same age and model.

Is this what you have installed; is it OEM?

Have the OEM coupling.   For me works good.   My story, bought Shamrock she was 5 years old about 400 engine hours, the cutlass bearing was worn, second season I changed cutlass bearing and aligned engine, was out of line quite a bit don't think the selling dealer did his job commissioning.  Since then I've put 1200+ engine hours on, is smooth and the cutlass bearing is just starting to wear, still good for a few seasons.   
Jim

[pbyrne]

I guess that means this is not OEM.  I'll have to take a closer look and see who makes it.  I haven't found anything in the docs I have.

Any suggestions on who may have made it?

What does your boat look like?  We have approximately the same age and model.

Is this what you have installed; is it OEM?

Have the OEM coupling.   For me works good.   My story, bought Shamrock she was 5 years old about 400 engine hours, the cutlass bearing was worn, second season I changed cutlass bearing and aligned engine, was out of line quite a bit don't think the selling dealer did his job commissioning.  Since then I've put 1200+ engine hours on, is smooth and the cutlass bearing is just starting to wear, still good for a few seasons.   
Jim

[Patches]

Ditto what Jim said.  Coupler manufacturer should have torque specs for bolting on the coupler.  I changed my coupler in December and used the torque specs from Buck Algonquin (non flexible).

[pbyrne]

At the moment I don't know who makes it.  I'll make another trip to the boat and see if I can find something on it that will identify the manufacturer.

Who are the top manufactures for couplers?  Maybe I can get lucky searching their site.

Ditto what Jim said.  Coupler manufacturer should have torque specs for bolting on the coupler.  I changed my coupler in December and used the torque specs from Buck Algonquin (non flexible).

[Stu Jackson]

Do you think this is a standard installed part of a 2000 34 MKII?

I'm getting the impression that it's a bit of an unknown...


I guess that means this is not OEM.  I'll have to take a closer look and see who makes it.  I haven't found anything in the docs I have.

Any suggestions on who may have made it?

It is not OEM.  All C34s came with a standard stuffing box.  It's in your boat manual.

There are only a few different options.  If I was looking for what it could be, I would Google terms like

---  alternate stuffing box material

---  prop savers

unless somebody here knows and pipes up.

Good advice so far about those nuts and bolts.

Good thing you caught it in time.

Good luck.

[Noah]

Looks like an R&D brand?
http://www.randdmarine.com/flexiblesc.asp

[Robert Mann]

I'm with Ken, the bolts are too short for the locking nuts and are not contacting the locking media.  Buy longer bolts and new ny-lock nuts and tighten them up.

[pbyrne]

That looks like a close match.  How do you take the bolts out without completely disassembling the unit?

Looks like an R&D brand?
http://www.randdmarine.com/flexiblesc.asp

[Ron Hill]

Guys : I agree with Kevin, that flexible coupling was not installed properly!!!

It appears that the nuts are nylon lock nuts and NO torque is required!!  With that type of nut the normal rule is to have at least 1 (best 2) thread showing!!  I believe that the bolts with the nuts on the transmission side just need to be tightened so there is 1 thread outside the nut or at least part of 1 thread!!

If you can't get a thread on the outside of the nuts, then get a thinner lock nut!!  Simple as that !!

A few thoughts