We just installed a new 50 hp Beta Marine engine and love it, it came with a new transmission, however when shifting there is a noticeable rather loud "clunk" sound. Doesn't matter if shifting from forward to reverse or reverse to forward. The mechanic says all small clutches do that. Any suggestions?
Noise when shifting
- Thread starter Turner
- Start date
The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
RT Firefly
Enigma
Greetings,
Mr. T. "Any suggestions?". Get another mechanic?
Mr. T. "Any suggestions?". Get another mechanic?
Ski in NC
Technical Guru
What gear are you using?
Most of those smaller engines use a mechanical shift gearbox like the ZF 15, ZF 25, etc. These are derived from the Hurth HBW 150, 250 etc. It is normal for these the "clunk" on a shift and rattle in gear at dead low idle. Most of these go into sailboats, where they are more tolerated.
Hydraulic shift gearboxes are much quieter. That is why the Velvet Drive is called Velvet Drive.
There are smaller hydraulic gears available, but I am not current on what is in the market now. Check ZF website.
Most of those smaller engines use a mechanical shift gearbox like the ZF 15, ZF 25, etc. These are derived from the Hurth HBW 150, 250 etc. It is normal for these the "clunk" on a shift and rattle in gear at dead low idle. Most of these go into sailboats, where they are more tolerated.
Hydraulic shift gearboxes are much quieter. That is why the Velvet Drive is called Velvet Drive.
There are smaller hydraulic gears available, but I am not current on what is in the market now. Check ZF website.
Last edited:
angus99
Guru
Interesting, Ski. We have a Velvet Drive on our port engine that is totally quiet when shifting. The Twin Disc (MG5011SC) on our starboard engine has a mild “clunk” every time it shifts into gear—even after lowering idle speed—and I’ve often wondered about it.
Ski in NC
Technical Guru
A little noise is normal even with a hydraulic gear when shifting and at idle. Some more than others.
Compared to a mechanical gear, which is more like a bucket of rocks! (not quite that bad..)
Compared to a mechanical gear, which is more like a bucket of rocks! (not quite that bad..)
FF
Guru
- Joined
- Oct 12, 2007
- Messages
- 22,552
A high idle speed will make shifting louder.
Cigatoo
Guru
As Ski said a mechanical gear with mechanical clutches will give a good clunk in and out of gear. The problems arise when that solid clunk becomes a “chatter”.
If it really concerns you get it on record with the distributor that sold you the engine and gear. They should be happy to send a rep to listen if asked.
Be sure to follow the maintenance / fluid change schedule as outlined by Beta.
If it really concerns you get it on record with the distributor that sold you the engine and gear. They should be happy to send a rep to listen if asked.
Be sure to follow the maintenance / fluid change schedule as outlined by Beta.
North Baltic sea
Guru
Hi
Is the clutch a hydraulic or mechanical conical coupler, which belongs to keep a loud voice clunk like stendrivers at switches.
NBs
Is the clutch a hydraulic or mechanical conical coupler, which belongs to keep a loud voice clunk like stendrivers at switches.
NBs
Ski in NC
Technical Guru
Depends on how much the noise now bothers you. I ran a planing skiff with a 50hp diesel and mechanical Hurth box for about six years, every time I shifted it grated on my nerves. At that point going hydraulic would have required changing mounts, shafting and plumbing so I just sucked it up and motored on.
If cost is not that high, I'd go hydraulic.
What is a PRN soft box?
If cost is not that high, I'd go hydraulic.
What is a PRN soft box?
Cigatoo
Guru
What Ski said. You might want to run the existing gear for a while. You might get used to it. I ran mine for 16 years.
We sent a video to the dealer, he wasn't concerned, just something we'll get used too. Love the engine, uses very little fuel. Thanks to all for the input.
Nomad Willy
Guru
I had a Kanzaki gearbox (aluminum) that was manual. It was smal as was the engine. I was embarrassed every time I came into the harbor. The engine was a 3cyl Yanmar. I mixed up a brew of the highest viscosity gear oil I could find. That did help some but not enough.
I ended up buying and installing a bronze gear on gear hydraulic pump and plumbing it to circulate the oil in the trans to a heat exchanger and back to the trans. It worked. The viscosity stayed high enough to make the shifting reasonably quiet. One of my “mods” that was very sucessful. Expensive though.
I ended up buying and installing a bronze gear on gear hydraulic pump and plumbing it to circulate the oil in the trans to a heat exchanger and back to the trans. It worked. The viscosity stayed high enough to make the shifting reasonably quiet. One of my “mods” that was very sucessful. Expensive though.
Similar threads
