Tranny reversing gear problem

[RFerraro1]

On a 1984 Beneteau First 32 with Renault engine.
Forward gear runs fine but in reverse the propshaft seems to slip, or turn slowly even when the engine revs up. This problem only arose after I replaced the stuffing box which required some heavy duty heat, and pounding to free the driveshaft from the collar connecting it to the transmission. I must have done some damage but I'm hoping it just needs an adjustment. All ideas welcome. Could it be that the clutch is slipping, and if so what does it take to fix it?

 

[higgs]

Sounds like an issue you should take up with a qualified Renault service center. This engine is not very common, but perhaps you will find someone on the forum who knows it

 

[Manny]

What model Renault is it? If it has a cone clutch on the reversing gear like my little RC8D it may just need to be adjusted.

Manny

 

[RFerraro1]

Thanks

What model Renault is it? If it has a cone clutch on the reversing gear like my little RC8D it may just need to be adjusted.

Manny

Hi and thanks. The engine has a complicated pedigree. It is a Renault 2.6 but on a Kobatu (SP?) block. Renault's marine business was taken over by Nanni, and the engine is really just like the Universal 18 which I believe is from the same Kobatu block. However, the transmission is marked H 485 which I take to be a Hurth. What is a cone clutch and how is it adjusted??

 

[Stu Jackson]

It's spelled KUBOTA

It is a Renault 2.6 but on a Kobatu (SP?) block. Renault's marine business was taken over by Nanni, and the engine is really just like the Universal 18 which I believe is from the same Kobatu block. However, the transmission is marked H 485 which I take to be a Hurth. What is a cone clutch and how is it adjusted??

www.marinedieseldirect.com has the information you need for the engine. You can buy less expensive (much less) parts at a local Kubota tractor dealer, and can find them by doing a search for the Kubota website and finding local dealers. You'll need to know the tractor engine Kubota model, which is different than the M18 nautical designation. I don't know the M-18 equivalent, someone here will.

The Hurth transmission, usually the choice of transmissions with the Kubota engines. can be found by dong a Google search on Hurth transmissions for Hurth boat transmissions. Sorry, I just don't have a link to Hurth in my bookmarks.

Before you start ripping the transmission apart, you may want to take another look at your stuffing box, which could well be whacked given your description of the work you described. It could be way too tight, or you may have messed with the stern tube and the fabric reinforced hose that connects the stern tube to the stuffing box.

 

[RFerraro1]

thanks stu

Thanks Stu.. at least I had all the Kubota vowels right. I think the new stuffing box is ok since there is no problem in forward, only reverse, but I'll back it down anyway to see if that helps. Before I tear into the transmission I want to try disconnecting the cable to the shift lever and see if I can push it into gear by hand. There is a cotter pin attachment at the lever, do you know if that is where the cable should be disconnected? I'm hoping that will work and all I have to do is adjust the cable throw. However, if the reverse still fails to kick in with ooomph I guess it'll be time to try the local tractor dealer.

www.marinedieseldirect.com has the information you need for the engine. You can buy less expensive (much less) parts at a local Kubota tractor dealer, and can find them by doing a search for the Kubota website and finding local dealers. You'll need to know the tractor engine Kubota model, which is different than the M18 nautical designation. I don't know the M-18 equivalent, someone here will.

The Hurth transmission, usually the choice of transmissions with the Kubota engines. can be found by dong a Google search on Hurth transmissions for Hurth boat transmissions. Sorry, I just don't have a link to Hurth in my bookmarks.

Before you start ripping the transmission apart, you may want to take another look at your stuffing box, which could well be whacked given your description of the work you described. It could be way too tight, or you may have messed with the stern tube and the fabric reinforced hose that connects the stern tube to the stuffing box.

 

[Bob S]

I just changed my tranny oil. I was reading in my manual that the most common problem is the linkage adjustment. I believe it's 1-3/8 either way from neutral. Maybe it's as simple as that. I hope so. It looks like a real pita to remove a transmission, at least in my boat.

Good Luck

 

[Stu Jackson]

Transmission linkage

There is a cotter pin attachment at the lever, do you know if that is where the cable should be disconnected? ...However, if the reverse still fails to kick in with ooomph I guess it'll be time to try the local tractor dealer.

Use the link I provided to the engine website and find your engine and the transmission linkage blow up diagram. It'll show you how it works.

If that doesn't work, then Kubota won't necessarily be folks to help you, you'll most likely have to contact Hurth.

 

[sailaway78]

Linkage

Very first thing I would do is find out exactly which tranny you have, and get information specifically for it. On transmissions with a cone clutch, adjustment can be critical. Is even a special tool for some of them.. On mine, was having a little problem with it slipping/jumping at mid range in forward. Connector bolt on the linkage was loose, and just didn't quite pull it all the way into gear. All it took was replacing bolt, proper tightening with a nylock nut do keep it in place.

 

[RFerraro1]

Problem Solved!

I am happy to report the problem of the weak reverse gear has been solved and the fix might be instructive to others. Turns out it was nothing major with the clutch or tranny, just an adjustment that was needed to the cable-to-lever connection. What is so surprising is how small a distance in the cable throw made such a huge difference in performance.

I started with the tranny in reverse and the engine running (the prop as usual turned fitfully and very weakly even when revved up). While in gear and with the engine running I grabbed the lever on the transmision, with the cable still attached, and pulled it back by hand (no mean feat given the contortion needed to access it). To my surprise with just the slightest back pressure on the lever the prop started to spin with real force.

Now that I understood what needed to be done, the problem was how to adjust the cable to bring the lever back to the critical point of contact. At first I thought I'd try to adjust the connection at the point where the cable meets the lever, but it was impossible for me to warp my body into the pretzel shape needed to reach and work on the cable, even if I knew how it adjusted, which I didn't.

But then I thought that by just bending the bracket which supports the cable back a bit it would accomplish the same thing as shortening the cable. So again with the engine running and in gear I pushed back on the bracket by hand, and with just that little pressure.. probably not more than an eighth, or quarter inch, the gear engaged fully. So I took a wrench and gently leaned onto the bracket just enough to bend it slightly back (to what I assume was the original position before we started manhandling the stuffing box). I must emphasize it is so slight a bend you can't notice any difference. But the bracket has kept its new shape and the transmission works beautifully both forward and reverse.

So thanks to all for your input, and I hope my experience is helpful in understanding how important the slightest change in the distance the lever moves.

 

[Stu Jackson]

Nice fix

elegant and simple. Thanks for reporting back.