Temp alarm with apparent normal temps

Nov 26, 2008
1,970
Endeavour 42 Cruisin
Perkins 4.154-200
Been sitting on a mooring field in S fl so I'm pretty sure the root cause is a heavily fouled prop.
Temp alarm was replaced 2 years ago so it should be fine.

We went out and motored fairly hard for about 4 hours. When we were coming back in, the whole drive train started vibrating. No vibration in neutral. Tried reverse several times, thinking we picked up something. Didnt seem to help. Dropped anchor for about an hour to attend to something else. Started up and all seemed fine. But 15 minutes later the alarm goes off. Slowed way down and went below. Heat gun checks found nothing extreme. That is what I am most perplexed about.
We went to the mooring and shiftin into reverse I start hearing nasty crunching sounds! No noise in forward. I suspect its barnacles that found their way into my max prop.

So most of this is likely from a very crusty prop.
The only mystery is why the engine alarm when nothing seemed hot by multi heat gun readings.
 
Nov 26, 2008
1,970
Endeavour 42 Cruisin
Upon further review...

I can move the prop shaft fore and aft several inches now. That's OK, right? The shaft wobbles a bit too. Nothing to worry about. And there's some kind of oily fluid at the back of the trans. Wonder where that came from. What a coincidence that this shows up right when I start having big vibrations under power. Probably nothing!
 
Jul 14, 2015
840
Catalina 30 Stillhouse Hollow Marina
Upon further review...

I can move the prop shaft fore and aft several inches now. That's OK, right? The shaft wobbles a bit too. Nothing to worry about. And there's some kind of oily fluid at the back of the trans. Wonder where that came from. What a coincidence that this shows up right when I start having big vibrations under power. Probably nothing!
Are you joking, or serious about not being a problem?
 
Nov 26, 2008
1,970
Endeavour 42 Cruisin
I could ask the same thing :)

I was thinking I could rev up to full throttle and drop it into reverse, maybe that will knock it back into alignment. If I build up enough heat, maybe the oil leak will reseal itself too? :)
 
Nov 6, 2006
10,095
Hunter 34 Mandeville Louisiana
Woof! None of that sounds good.. maybe it will "buff out"?? But prolly not.. Sounds like a thrust bearing is failed in the gearbox? or shaft loose in coupling.. Yup Revving up to full power and dropping in reverse would do something.. that's for sure.. Let us know what ya find as the hunt progresses.
 
Nov 26, 2008
1,970
Endeavour 42 Cruisin
Coupling is tight. Bearing sounds likely with the oil leak.
Some Mainesail butyl tape and she'll be good as new.
 

SFS

.
Aug 18, 2015
2,088
Currently Boatless Okinawa
Don't ask me how I know this, but you might want to check the strut. Has nothing to do with the overheat alarm, but noises and vibration, absolutely.
 
Aug 26, 2015
21
Edel 820CC Whitby,ontario
the vibration may have loosened the temp sensor connection. itll be a direct acting thermistor so an increase in resistance by say a loose wire will cause the system to see an increase in temperature. for the vibration some 5200 and duct tape should get you out of trouble. and if not maybe invest in a really big paddle.
 
May 24, 2004
7,174
CC 30 South Florida
Several inches of shaft play is not normal. With the crunching sounds and an oil leak it all points to a transmission problem. With the transmission in neutral see if the shaft turns freely by hand.
 
Nov 6, 2006
10,095
Hunter 34 Mandeville Louisiana
Gettinthere.. rub a it of Robitussin on the coupling.. it'll be OK
 

Sailm8

.
Feb 21, 2008
1,750
Hunter 29.5 Punta Gorda
This sounds like a problem that will require a liberal swathing of $100 bills. Many swathing, good luck.
 
Feb 9, 2009
19
2 26 Lake Tahoe
Quick, wire me $5,000 then place your hands on your radio, I will pray for your problem.... Hmmm, not fixed? Send another $5,000 and we will pray some more.
 
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Sep 10, 2015
1
Passport 456 ct
Sounds like a transmission seal and probably a bearing. Check engine alignment - had a mount go after 12 years and the engine went out of alignment. Vibration and rumble - bent the shaft - caught it before I damaged the transmission seal or bearing. Also, check your max prop. Found out after 18 years that is should be sent back to the mgf for rebuild - blades wiggle a little - it's time. Crunching sounds - from the prop? Do you keep your max prop greased - grease nipple screws into the body. Can leave it there or - I remove it and keep it with my grease gun. Fore/aft looseness in the shaft - don't shift into reverse - the whole shaft, prop and all will back out leaving a nice big hole for water to come in. A shaft zinc on the inside between the transmission and the thru-hull could save your boat.
 
Sep 14, 2014
6
Catalina 30 Norwalk, CT
I agree the vibration may have loosened the temp sensor connection or insulation wore out at one point and is grounding. High revs and throwing into reverse may be fun to see a trans case crack or explode. A much cleaner way might be rebuilding or replacing the trans.,. Just saying
 
Aug 28, 2015
190
Oday 28 St Joseph, MI
I would suggest you start the engine and give it full power. Do this before it warms up, we don't want that temp alarm going off now, do we? When it reaches full RPM's start rapidly shifting from forward to reverse, for at least 60 seconds, pausing in gear for two seconds. After the 60 seconds leave the engine in neutral at full power for another 60 seconds then repeat the process. When this has been done three cycles shut down the engine and call a mechanic.
 
Dec 29, 2008
806
Treworgy 65' LOA Custom Steel Pilothouse Staysail Ketch St. Croix, Virgin Islands
You could probably dive on the prop and eliminate the crustacean question...
 
Sep 3, 2015
3
Catalina C-22 Mt. Vernon, VA
Yep, send in that $5000 vow of faith and the Lord will fix it right up. [proceeds to start speaking in tongues]
 
Sep 3, 2015
3
Catalina C-22 Mt. Vernon, VA
uh, really, maybe take it to someone who works on these things for a living... Sometimes ya just gotta pay what ya owe. Or be a cheap ass, don't do nothing and have it take a crap, blow up and maybe sink. That would be entertaining.