I have a CS36 sailboat with a Yanmar 3Jh4E with Campbell a sailor prop. Yesterday the lazy sheet for my asymmetrical ended up getting wrapped around my Free spinning prop, transmission was in neutral as specified by Yanmar. When I put the transmission in reverse it continued to spin freely. When I got the boat stopped and dove down to untangle the sheet I found that the prop could easily be turned when in forward or revere with the engine off. When I started the engine I could make way in forward or reverse. I don't understand how it is possible to freely spin in gear with the engine off but to be able to make way with engine running . Probably something simple but I am confused and would appreciate advice.
prop spins even when engine is off and in gear
- Thread starter JensJaunt
- Start date
it's the same principal as the automatic transmission in a car the transmission only bites when the engine is turning the power shaft in the transmission that is why you are supposed to only sail with it in neutral or otherwise you will burn up the clutch cones in the transmission ......
If you don't have a folding or feathering prop it is standard practice to have a shaft brake to stop the prop from spinning underway. These usually operate hydraulically from the trans oil pressure, so you won't be putting the boat in gear while the shaft brake is on.
If the prop spins while holding the shaft (motor not running:naughty
then the key has fallen out or sheared.
You'll need to remove the prop and inspect the key.
What doesn't make sense is that you get forward/reverse speed with the motor running.
then the key has fallen out or sheared.You'll need to remove the prop and inspect the key.
What doesn't make sense is that you get forward/reverse speed with the motor running.
A standard transmission (not one with a toqure converter/auto) should not be able to spin when in gear without also spinning the engine.
First question, is the engine also spinning?
probably not as you would have noted that in your post
second question, can you develop full hull speed?
if not then your cone clutches are slipping (or you have an engine output problem or a durty bottom. Assuming it is not the last 2 and your clutch cones are in fact slipping then that would also explain how the prop can spin while in gear and with the engine off.
What transmission do you have?
First question, is the engine also spinning?
probably not as you would have noted that in your post
second question, can you develop full hull speed?
if not then your cone clutches are slipping (or you have an engine output problem or a durty bottom. Assuming it is not the last 2 and your clutch cones are in fact slipping then that would also explain how the prop can spin while in gear and with the engine off.
What transmission do you have?
Jens,
I see no need for setting the tranny to neutral when sailing unless, you're racing.
Leaving it in neutral will cause needless wear in your cutlass bearing & stuffing box.
You'll also get the humming of the spinning shaft especially going below.
I have a Hurth tranny. In the manual it states to lock the shaft, use reverse. It also states not to set it in forward gear for this.
Check your engine manual, or go online & find a manual for your tranny. I'm sure you will find what they require.
CR
I see no need for setting the tranny to neutral when sailing unless, you're racing.
Leaving it in neutral will cause needless wear in your cutlass bearing & stuffing box.
You'll also get the humming of the spinning shaft especially going below.
I have a Hurth tranny. In the manual it states to lock the shaft, use reverse. It also states not to set it in forward gear for this.
Check your engine manual, or go online & find a manual for your tranny. I'm sure you will find what they require.
CR
while all that may be true ....yanmar says to only sail in neutral on there products
Woods,
Yea, I'm not too familiar with Yanmar Trannys, that's why I said to check the manual.
But if correct, this neutral setting has to lead to unnecessary wear. There wear factor was why I posted.
CR
Yea, I'm not too familiar with Yanmar Trannys, that's why I said to check the manual.
But if correct, this neutral setting has to lead to unnecessary wear. There wear factor was why I posted.
CR
We have pretty much the same engine/tranny. If in gear, turning the prop also turns the engine (or tries to).
Does your prop have some kind of free wheeling clutch? I have heard of those as an alternative to feathering types - don't think they became popular though.
Yanmar is specific about leaving the transmission in neutral when sailing. They used to specify reverse but changed that several years ago (and it applies retroactively to all their drive units).
Chris
Does your prop have some kind of free wheeling clutch? I have heard of those as an alternative to feathering types - don't think they became popular though.
Yanmar is specific about leaving the transmission in neutral when sailing. They used to specify reverse but changed that several years ago (and it applies retroactively to all their drive units).
Chris
you are correct Ron but yanmar don't seem to care about the cutlass ware...i don't understand why they can put a pawl in the gearbox that will stop the spinning just like in park on an auto transmission
Wood,
I agree man, If Hurth can do it, what's up with the Yanmar engineers. I see many problems with products where the people that design them have never owned or used them....DUH! They just work from instruction. That makes for less-than-great background experience hence you say to yourself, why did they do it this way?
I wonder statistically, what the time between cutlass changeouts & stuffing box re-packing vs. those that can lock their shafts. Each haulout gets a new cutlass. For my bottom jobs, three on the hull & four at the water line. I use a scuba clean guy with a fine 3M pad. When he gets the last coat on the hull to 50%, I schedule the haulout. In the yard, they don't have to do alot of takedown sanding for prep work to get rid of the old paint buildup.
So with proper shaft alignment, I get 4 years on my cutlass bearing & I sail frequently. And, my PSS shaft seal still has alot of graphite on the collar for the last 8+ years.
CR
I agree man, If Hurth can do it, what's up with the Yanmar engineers. I see many problems with products where the people that design them have never owned or used them....DUH! They just work from instruction. That makes for less-than-great background experience hence you say to yourself, why did they do it this way?
I wonder statistically, what the time between cutlass changeouts & stuffing box re-packing vs. those that can lock their shafts. Each haulout gets a new cutlass. For my bottom jobs, three on the hull & four at the water line. I use a scuba clean guy with a fine 3M pad. When he gets the last coat on the hull to 50%, I schedule the haulout. In the yard, they don't have to do alot of takedown sanding for prep work to get rid of the old paint buildup.
So with proper shaft alignment, I get 4 years on my cutlass bearing & I sail frequently. And, my PSS shaft seal still has alot of graphite on the collar for the last 8+ years.
CR
Just got off the line with a technician at Mastry, our local Yanmar distributor here in St. Pete. He advised to sail with tranny in neutral because if the prop does rotate, even a fraction of an inch in gear, it could cause premature wearing of the cone clutches. They are also much more expensive to replace than a worn cutlass bearing. Told him I only sail with the tranny in reverse to prevent this but, his reply was that it may turn anyway. I have a 3YM20 with only about 360 hours on it. Will have to check the prop for any rotation while stopped and in gear next time I dive it.
Roland
s/v Fraulein II
Roland
s/v Fraulein II
Roland,
I'm close by in John Pass, I guess that means were neighbors sorta.
Alot of my friends here in the area use Mastry.
One thought, many times the engine manufacturer uses a different manufacture's. transmission. If it were me & this were true, I would contact the tranny maker to see what HE recommends, not Yanmar.
I could be wrong & it's Yanmar that also makes the tranny but hey, if you don't ask, the right questions, you may not get the right answers. Dig alittle deeper pal. SCOTM... may be correct in his thoughts, I dunno.
I know I will take HITS for this. But hey, any phone voice can be incorrect in what they tell you. Just make sure you have independent confirmation. It has to pass thru the tranny first, before the engine will spin.
CR
I'm close by in John Pass, I guess that means were neighbors sorta.
Alot of my friends here in the area use Mastry.
One thought, many times the engine manufacturer uses a different manufacture's. transmission. If it were me & this were true, I would contact the tranny maker to see what HE recommends, not Yanmar.
I could be wrong & it's Yanmar that also makes the tranny but hey, if you don't ask, the right questions, you may not get the right answers. Dig alittle deeper pal. SCOTM... may be correct in his thoughts, I dunno.
I know I will take HITS for this. But hey, any phone voice can be incorrect in what they tell you. Just make sure you have independent confirmation. It has to pass thru the tranny first, before the engine will spin.
CR
Captnron, good advice. I will get the tranny make and call them. Thanks for the heads up. If you're ever up here in the Tarpon area give me a holler at Anclote Isles Marina, slip 26.
Roland
s/v Fraulein II
Roland
s/v Fraulein II
There is a V drive between the transmission and the shaft, I am not sure what make the transmission but I assumed it was made by Yanmar.
Here is some information based on other posts...
The shaft does turn when the prop is turning so I think the key is in place...
I had a folding prop before so I never heard the prop spinning while sailing in or out of gear. I this fixed blade installed about a month ago...
I guess it may be normal based on what many of you said.
I don't believe Yanmar makes any transmissions. Even so, I'm pretty sure their instructions to keep the tranny in neutral is sound and based on their instructions from the manufacturer.
The prop does spin with the engine in gear when the engine is not running. When the engine is running and put in gear, tied to the dock it tries to break free from mooring lines. I watched the strain on the lines and watched the shaft at the V drive to see if it slipped but it did not.