Hurth 100 transmission issue

[Rockinar]

My Hurth 100 is having trouble engaging in forward drive. Its not the cable or anything like that. Ive checked and tried to do it by hand. My first thought was the clutch packs are toast, but it has no problems engaging in reverse. Dont forward and reverse use the same clutch packs? If it was the clutch packs wouldnt reverse not work also?

Normally when you put it in forward or reverse theres a slight audible “clunk” and you know its in gear. It does not do that in forward. You put it in forward and theres nothing. If youre lucky it will eventually kick in. If it does, you’re fine and can motor. Its just originally getting it to kick in. Im stumped.

[capt jgw]

Separate clutches for fwd and reverse not unusual for one to fail and the other keep working. It can be rebuilt but it's expensive. I had the same problem with the HBW50 on my boat, I replaced it with a New Age PRM60 from ASAP Supply in the UK. Was about the same cost as parts alone to fix the Hurth. Note that thier prices listed are "VAT included." Ship to the US and drop the VAT, it's like 20 percent. Beta uses the NewAge gears on some of thier models so they must be good. I believe the PRM90 is equivalent to the HBW100. Ran it two seasons before I sold the boat, it worked flawlessly. It's a drop in replacement, everything's the same except the shift cables on the port side and goes the other way. (Fwd for fwd, the Hurth goes aft for fwd. ) I had to fabricate a new cable bracket and reverse the shift cables direction in the control lever assembly. Both were simple to do. If your control lever is not reversible, just turn the shift lever around on the trans. It comes pointing up but if you take it off and put it back on pointing down it will go the right way. You have to make a new cable bracket anyway so just angle it to fit.

[capt jgw]

The problem with the Hurth gears are the disc clutches. They're held in gear by shift lever pressure alone and as they wear the pressure decreases causing them to slip. The more they slip the more they wear. The PRM has cone clutches like the Kanzaki's used by Yanmar. Rotation forces the cones tightly together so there's no slipping. The shift lever only gets the process started. Much stronger and more reliable.

[donradcliffe]

I'm pretty sure there are separate clutches. I had a similar problem with hesitation going into reverse. I remember looking at the Hurth manual and it talked about changing shims. When one of my buddy boats had problems with his going into forward, he sent it off to a shop in Brisbane Australia. They said they found evidence of salt water inside, but were able to rebuild it.

When I got to Brisbane I pulled the tranny and sent it off to the same shop. They tore it down and said they could find nothing wrong with it so they just reassembled it and charged me $A200. I put it back in the boat and it worked fine until I repowered 8 years later.

[Rockinar]

Originally Posted by capt jgw

Separate clutches for fwd and reverse not unusual for one to fail and the other keep working. It can be rebuilt but it's expensive. I had the same problem with the HBW50 on my boat, I replaced it with a New Age PRM60 from ASAP Supply in the UK. Was about the same cost as parts alone to fix the Hurth. Note that thier prices listed are "VAT included." Ship to the US and drop the VAT, it's like 20 percent. Beta uses the NewAge gears on some of thier models so they must be good. .

Yeah Im betting clutch pack. Im farked. Trying to decide what would be less headache. New tranny or headache of waiting on parts and a mechanic to rebuild cause Im out of state in Florida and stuck in a marina.

[sail34]

HI
I had the same problem with my Hurth v drive. At the time I found a post from years ago
I drained the oil, filled the trans with kerosene, started the engine and in idle worked the trans from forward to reverse a number of times 30 or so, drained out the kerosene, and refilled with trans fluid. this lasted me 6 years, 15000 miles before I had to rebuild the clutch pack
Good luck

[RigBig]

I have a C36 and HAD a Hurth 100 transmission and it was doing the same thing. Its only going to get worse and finally one day its going to give it up. I replaced with a ZF150.

[Peter K]

I just ordered new clutch and gasket / seal kit from Hale Marine , 560 usd.
Cable travel is critical on these units as if the throw isn't enough the disc's quality wear prematurely

[sesmith]

In most cases, it comes down to a worn thrust washer on that transmission, I believe. Causes it to not put enough pressure on the clutch pack in forward.

I had my ZF15 MA (same as Hurth 150) rebuilt a couple of years ago for the same problem. Rebuild parts are pretty expensive (around 1k just for parts) so if you can find a new one for a decent price it could be worth it. If you're anywhere near Charleston, I can recommend a rebuilder here. He's factory trained and reasonable.

[Rockinar]

Originally Posted by RigBig

I have a C36 and HAD a Hurth 100 transmission and it was doing the same thing. Its only going to get worse and finally one day its going to give it up. I replaced with a ZF150.

Was that a drop in replacement or needed mods?

[Marutji]

Originally Posted by Rockinar

My Hurth 100 is having trouble engaging in forward drive. Its not the cable or anything like that. Ive checked and tried to do it by hand. My first thought was the clutch packs are toast, but it has no problems engaging in reverse. Dont forward and reverse use the same clutch packs? If it was the clutch packs wouldnt reverse not work also?

Normally when you put it in forward or reverse theres a slight audible “clunk” and you know its in gear. It does not do that in forward. You put it in forward and theres nothing. If youre lucky it will eventually kick in. If it does, you’re fine and can motor. Its just originally getting it to kick in. Im stumped.

hi
Rockinar,

Mine was just sticking I simply stripped mine and re-assembled it, making sure everything was moving as it should all the time. Right as rain. took about 5 hours (on christmas day!) and cost nothing.

[Uncle Bob]

My hurth 150 turned into a slipomatic and for not much more that the repair cost replaced it with a PRM 120. Easy as and absolutely no problems to date (touch wood ).

[peter loveridge]

I had 4 HBW 50 transmissions. The ones made in Germany lasted, the ones made elsewhere failed miserably, one after 25 hours. One problem is that I assumed it needed LH prop. The manual was not clear, which meant the idler was running all the time in ahead. Finally replaced with a twin disc, which has bronze cone clutches and seems pretty indestructible. Almost a drop in replacement, all the bolt holes are the same, shifter is on the other side, but easy enough to make . Kept the old Hurth, which seemed ok after 1000 hours ( had it checked out, just needed new rear seal) as a spare

[double u]

Originally Posted by capt jgw

The problem with the Hurth gears are the disc clutches. They're held in gear by shift lever pressure alone a...

I'm very sure there are ramps, increasing pressure as the torque comes on. No way lever pressure alone is sufficient. Kanzaki plate-clutch gearboxes (on Yanmars) sure had ramps, I saw them.

[Shoalbay]

See https://www.cruisersforum.com/forums...es-8248-7.html for info.
#94 by Machinist Gary
#140 & #147 by Shoalbay