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bwindrope 12-20-2012 12:34 PM

Hurth engagement question
So my Hurth 100 is beginning to have hesitation with engaging, and I have checked and adjusted all my lever play and it is still happening. What occurs is that you put her in gear, solidly, and she goes into gear smoothly with no problem, but then at idling RPM will not fully engage. You can hear it slip into and out of gear, knocking around a bit, until you increase the RPM and then she stays in gear. So full travel in gear, but still skipping around until RPM increases. Obviously this is not good and I'm seeking my approach to solution.

I have a basic understanding of these transmissions, but would appreciate some help. Is this a damper plate problem? Is it likely that the plate is worn and simply needs replacing? To my knowledge it is original (24 years and 1,000+ hours).

Or it is more likely to be something with the internal gears and cones?

Any experienced insights appreciated!

deniseO30 12-20-2012 02:14 PM

Re: Hurth engagement question
mine just didn't go in gear! changed the fluid (it needs to be replaced often I found out) dot3 fluid I think it needs.

Faster 12-20-2012 02:20 PM

Re: Hurth engagement question
We had a similar issue on a previous boat.. wouldn't go into gear, but when I removed the shift arm plate I was able to push the shuttle mechanism inside by hand and it engaged OK.

I took the plate, lever and actuating cam to a machine shop and had them build up the 'cam' a little so it would push the internal 'shuttle' farther. Worked fine for the remainder of our ownership (another 3-4 years, IIRC)

bwindrope 12-20-2012 05:59 PM

Re: Hurth engagement question
Hey Faster, thanks, and hope you are doing well up there. Saw Smith Island has been having 50 knot winds and that the northern Salish Sea has been getting its usual winter punishment. Love it.

Your suggestion sort of hits a nail on the head, which is whether my trouble is fixable by me, and worth the trouble and time, or whether it's time for a new one. New they are about $1,200 and rebuilt is not much less. I'm quite capable for a home mechanic, but don't have lots of extra time, especially when the tranny is pulled.

I'm hoping some more people might have particular expertise with Hurth being fully engaged easily but not sticking in gear until revved up a bit. More ideas welcomed.

PorFin 12-20-2012 07:16 PM

Re: Hurth engagement question

I've never torn into my HBW-100. That said, I did a fair amount of reading up on the box while contemplating doing an overhaul myself. I eventually decided to take it to a transmission shop and have them pop it on a dynamo-meter to check its health. They gave it an OK, and since they had it I had them replace the seals.

If you haven't changed your ATF recently, you might see some improvement once you do.

Another SWAG in addition to the ones already mentioned:
- Clutch plate wear.

deniseO30 12-20-2012 10:23 PM

Re: Hurth engagement question

Originally Posted by PorFin (Post 964975)

If you haven't changed your ATF recently, you might see some improvement once you do.

I didn't believe it either until we changed the fluid

bwindrope 12-21-2012 07:29 PM

Re: Hurth engagement question
I change the fluid in my tranny every year or about 100 hours. I'm about to change it again as part of my winter maintenance, but don't suspect that is my issue.

I can't really deal with the tranny until she is hauled out, easily, and once she is out the clock is racing and the money spending. It's just not a time when I can bring the tranny home and spend 2 week carefully taking it apart and then to a machine shop and all that. Even though that is a logical and good thing to do.

As a practical matter, when I have the boat hauled, I can pull the tranny and replace the damper plate and put it back together and then back in the water but if that doesn't fix it...

I guess it may be possible to pull my tranny while Aeolus is in the water, I haven't thought about it much. I have and love a PSS shaft seal, so I suppose I would only need to push that back enough to free up the tranny...

Faster 12-21-2012 07:49 PM

Re: Hurth engagement question
Do be careful of relieving the pressure on that seal.. it's often the 'push' from the coupling position that maintains the pressure. If the bellows can 'push your prop shaft' inboard that will end up releasing some of the seal pressure. Perhaps more of an issue with a strut/shaft than a prop in an aperture like you have.

When we pulled our gear with a PSS seal as a precaution I heavily taped the collar to the seal just in case things 'slipped'....

To see if the actuating cam is worn down as I described it's simply release the control cable, undo 4 bolts that hold the plate on and the lever and the internal cam come out clean.. though I suppose your access may not be that great with the engine deepish in the bilge.

Rockter 12-22-2012 05:44 AM

Re: Hurth engagement question
Really, the transmission should come off with the boat in the water.
Disconnect the final drive, take off the flexible coupling, and push the driveshaft aft.
The gearbox should come off then, or someone has overlooked a basic.
The idea of having to lift a boat out of the water, disconnect the prop, drift off the final drive coupling and pull the propshaft out just to get the gearbox off is a monumental design error.
I doubt if anyone has been that stupid.

bwindrope 12-22-2012 11:02 PM

Re: Hurth engagement question
There is no question the tranny on a Gulf 32 CAN be removed with the boat in the water, it is more that I haven't given it any thought and would need to work around the PSS seal as Faster mentioned.

I plan to call a few tranny shops and ask their opinion of my question here, and if I learn anything of value from them I will try to post it here. Whatever final solution I pursue, I will also post.

Happy post-solstice everyone!

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