Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 08-12-2007, 13:08   #1
Senior Cruiser
 
rebel heart's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Posts: 6,190
Images: 3
Screw (prop) keeps turning

I hadn't fired up my engine in a few weeks, so I fired up my Yanmar 4JH2 (52 hp / non turbo / installed in 2000 new). I was checking all my levels, and am happy to report that oil pressure, engine temp, and coolant levels are all fine. I'm sitting in the cabin right now as I let it run for another hour or two.

I'm ashamed to admit it, but while poking around looking at my fuel filters (dual racor 500's), I notice the shaft spinning ever so slightly. Something I should have id'd long ago to establish whether this is common or abnormal. I'd estimate maybe 1 revolution every 30 seconds or so, and it's timed with the engine. Rev up, and it spins faster. This is in nuetral.

I put it in gear, then gave forward throttle. Boat goes forward.

I put it in gear, then give reverse throttle. Boat goes backwards.

This is normal for me to have a bit of constant motion on the shaft, even when I'm not in gear?
__________________

__________________
rebel heart is offline   Reply With Quote
Old 08-12-2007, 13:14   #2
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
Hey rebel...
Depends...some trannys I have seen do this. My guess is it has something to do with the viscosity of the tranny oil spinning oil from the engine side to the shaft side although the clutch is in neutral...similar to what an automatic transmission does. Does gripping the shaft (safely) stop the turning? I have never seen anyone in the know worry about it. If it seems a concern you could always call the manufacturer to see if this is normal.
__________________

__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 08-12-2007, 13:28   #3
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
Aloha Rebel,

My Velvet Drive trans have always done it. Both boats had Velvet Drives. Both did it.

Kind Regards,

JohnL
__________________
SkiprJohn is offline   Reply With Quote
Old 08-12-2007, 19:58   #4
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
Yep they will turn. No worries, it is normal. However, you should have the thing in gear when warming up anyway. I place you on detention. Punishment is go to the StudyHall and read about warming up the engine. :-)
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 08-12-2007, 21:05   #5
Registered User

Join Date: Jun 2005
Posts: 1,901
Quote:
Originally Posted by Alan Wheeler View Post
Yep they will turn. No worries, it is normal. However, you should have the thing in gear when warming up anyway. I place you on detention. Punishment is go to the StudyHall and read about warming up the engine. :-)
detention isn't good enough for this felon.

Double Secret Probation for you sir.

Next time you abuse your engine this way, put it in gear and pull on the ropes.
This will stop the freewheeling that is normal and give the engine a healthy workout.
__________________
never monday is offline   Reply With Quote
Old 08-12-2007, 21:22   #6
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
One practical problem with warming up your engine while in gear...the wash and your neighbors. I guess it really depends on the size of your screws. My 24"x24"s wreak havoc. The guy behind me in the little sailboat probably has a 4 knots of current (close to hull speed) under his boat when I do that! (I am stern in to the dock)

I would probably end up in detention FOR doing that!

In all practicality, I let my engines fully warm up after getting out of the marina at just above an idle before going full ahead.
__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 09-12-2007, 00:14   #7
Senior Cruiser
 
rebel heart's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Posts: 6,190
Images: 3
Well, I do put it in gear (forward and reverse) for a bit to get it to temperature, but then I put it back in nuetral and it manages to keep the temperature from that point onwards.

The whole idea of "having load on it" is for the temp, right?
__________________
rebel heart is offline   Reply With Quote
Old 09-12-2007, 00:15   #8
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
Even if you can let it run at low revs while engaged in gear is better than nothing, ONLY if you are tied to the dock. But if you are intending to head out, then don't pre warm the engine. Simply get ready to go, start and then throw off the lines and motor. You won't be doing any great speed out the marina, so that is a good initial warming, then once you get out, you can start to place some load on it. Not full throttle, you do have to be sensible about it.
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 09-12-2007, 00:16   #9
Senior Cruiser
 
Alan Wheeler's Avatar

Cruisers Forum Supporter

Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
Images: 102
Quote:
The whole idea of "having load on it" is for the temp, right?
No it is to stop your bores from glazing up.
__________________
Wheels

For God so loved the world..........He didn't send a committee.
Alan Wheeler is offline   Reply With Quote
Old 09-12-2007, 00:34   #10
Registered User
 
stevensc's Avatar

Join Date: Nov 2007
Location: Thibodaux, Louisiana
Boat: Monk 36 Trawler
Posts: 679
turning props danger

A turning shaft is very dangerous! They love to grab and wrap loose clothing or long hair depending on how fast they are turning can rip your sleeves or pants legs right off with your arm or leg sill in them. This includes shafts while not powered but freewheeling while sailing or drifting. Don't get near them if they are turning even slowly!
Steve
__________________
stevensc is offline   Reply With Quote
Old 09-12-2007, 01:16   #11
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
Steve,
My propshaft will stop turning with hand pressure while in neutral.
JohnL
__________________
SkiprJohn is offline   Reply With Quote
Old 09-12-2007, 03:12   #12
Registered User
 
Celestialsailor's Avatar

Join Date: Nov 2006
Location: In Mexico, working on the boat
Boat: Hallberg Rassy 35. and 14ft.Whitehall pulling skiff.
Posts: 8,013
Images: 5
I have a 4JH also...It is older than your rated at 44hp. Great engine. Yes, it does slowly spin when cold and very slow when warmed up. My other engines did it too. A Volvo 2003(junk), and Westerbeke 4-107(the leaky legend). It is nothing to worry about. As Skiperjohn pointed out, they can be stopped by hand. Although my 4-107 had a paragon trans and if not adjusted perfectly it could spin uncomfortably fast.
Perhaps this could lead to a thread about sailing in gear or free spinning. I think that depends on tranny design. Anyone want to touch that one?
__________________
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: Wow - what a ride!"

http://wwwjolielle.blogspot.com/
Celestialsailor is offline   Reply With Quote
Old 09-12-2007, 10:37   #13
Senior Cruiser
 
rebel heart's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Posts: 6,190
Images: 3
I checked my 4JH2 manual and it told me to sail with it in nuetral. Which is great, because I had been doing it for a year before I bothered to check the manual. Fortune favors the foolish.
__________________
rebel heart is offline   Reply With Quote
Old 09-12-2007, 11:06   #14
Registered User
 
Celestialsailor's Avatar

Join Date: Nov 2006
Location: In Mexico, working on the boat
Boat: Hallberg Rassy 35. and 14ft.Whitehall pulling skiff.
Posts: 8,013
Images: 5
See...There you go. I have not read the manual. I just do not seem to have that gene. Im not sure if it is bad to sail with it in gear. I doubt it. I do know with some hydralic trannies, it is suggested not to let the screw free wheel. Mostly I let mine free wheel unless I hear a whine, then I put it in gear. Seems to me though that free wheeling would be less drag. Interesting topic I think.
__________________
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well-preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: Wow - what a ride!"

http://wwwjolielle.blogspot.com/
Celestialsailor is offline   Reply With Quote
Old 09-12-2007, 12:01   #15
Senior Cruiser
 
SkiprJohn's Avatar

Cruisers Forum Supporter

Join Date: May 2006
Location: Kea'au, Big Island, Hawaii
Boat: Cascade, Sloop, 42 - "Casual"
Posts: 14,192
If you do a bit of search on this forum you'll find the big discussion on "free wheeling" vs "in gear" controversy and how it effects the life of tranny and speed. The Velvet Drive folks have come to the conlusion that it doesn't hurt to have it free wheel. I'm not certain of the other trans makers.
JohnL
__________________

__________________
SkiprJohn is offline   Reply With Quote
Reply

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
How do you fix stripped screw beds? ssullivan Construction, Maintenance & Refit 15 18-11-2007 22:03
Which prop CARL Monohull Sailboats 11 17-09-2006 01:30
What Prop? Moby Dick Multihull Sailboats 27 28-07-2006 13:45
Who invented the Screw Propeller? GordMay Electrical: Batteries, Generators & Solar 6 13-01-2006 16:15
Is Mediterranean Climate Turning Caribbean ? GordMay Europe & Mediterranean 0 06-07-2005 11:50



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 20:06.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.