Universal M25 Bad Noise, Engine Stop

Sep 29, 2018
28
Catalina 30 Annapolis
I was out sailing in light wind last Saturday and started the engine to help get to my destination. When the wind started to pick up, I shut the engine off, but with the ignition, not the fuel cut off handle. The engine stopped immediately with a fairly heavy ka-thunk noise. I tried to start it back up and it did not turn over, just a thunk noise each time, almost as if the starter was barely engaging. Eventually, it started again, after struggling- almost as if the batteries weren't charged, and it ran for a while at 1500 rpm when it started to make an intermittent sharp clicking noise. In a short period of time, the noise became very rapid and the engine shut down hard. It has oil, had a constant flow of water out the exhaust and ran the entire time at 160 degrees. I got a tow back to my slip. Today, I disconnected the shift cable on the transmission lever as it was stuck in forward. This has been an intermittent issue, where it has been difficult to get it into neutral . I got the engine started after a few tries and it seemed to run OK for 30 or 40 seconds before the sharp clicking started slowly and then very rapidly before shutting down hard again.

I know I should have shut the engine off with fuel shot off handle, but thought that turning the ignition off might just impact my alternator.

Any thoughts?
 
Jan 5, 2017
2,263
Beneteau First 38 Lyall Harbour Saturna Island
Turning off the key shouldn’t have stopped the engine. The ka-thunk is something else. Not a diesel mechanic but I don’t believe your problem is related to turning off the key. Do keep us posted.
 
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Aug 12, 2020
53
Lancer 36 Pago Pago
How does your key switch shut off your engine? If you have no means to manually turn over your engine, time to get a marine mechanic involved; otherwise, I would remove the valve cover and manually turn the engine over while observing the action of the valves and pushrods, looking and listening for any obvious faults. Keep us posted:huh:
 
Jan 19, 2010
1,169
Catalina 34 Casco Bay
WE have the same engine. The engine stop handle mere shunts the fuel flow to the injector pump and basically starves the engine into stopping. The ignition key is just a security key. It allows power from the battery to run through the starter button and the electric fuel pump.

Turning off the key should not stop the engine ( initially). Eventually, with the key off the fuel pump will fail to provide.

I have a sense that the transmission shifting issue is the root of your problem..
 
Sep 29, 2018
28
Catalina 30 Annapolis
Not sure why the ignition would turn off a diesel engine. I know it should not, but the timing was immediate. I forgot one other time to similar affect. It doesnt make sense that it would have anything to do with the engine, but a strange coincidence, if not. Thanks for your replies. I'll send an update when I have more info.
 
May 24, 2004
7,129
CC 30 South Florida
If you have an electric fuel pump by turning off the key switch you actually cut power and fuel to the engine. My concern would be the shift cable and the fact the transmission was stuck in forward. How is the operation of the transmission when you are able to get the engine started? Will it continue to run if in neutral? Check the spinning of the shaft, see if you can turn it by hand and if the spinning when running is concentric. Two things come to mind, you could have picked up a line or plastic bag and wrapped it around the prop or the transmission gave out. Sailing with the transmission in forward with the engine off is not recommended by most manufacturers. If you were having difficulty engaging neutral chances are it is the transmission.
 
Sep 29, 2018
28
Catalina 30 Annapolis
Prior to last weekend, the engine seemed to run fine in neutral, fwd and reverse. On a few occasions, it was difficult to get it out of forward and back into neutral, but on others seemed to work fine. Th
 
May 24, 2004
7,129
CC 30 South Florida
Prior to last weekend, the engine seemed to run fine in neutral, fwd and reverse. On a few occasions, it was difficult to get it out of forward and back into neutral, but on others seemed to work fine. Th
I gather that you are now unable to get the transmission into neutral, is that correct? What were you doing on those few occasions when it was difficult to get into Neutral or was it random? You seem to have a drive train failure, something is broken and is not allowing the engine to turn freely as evidenced by the slow starter speed mimicking as if the batteries were really weak. There can be a few reasons why your drive train ain't turning freely; I had mentioned a line wrapped around the prop but it would be highly coincidental that it would happen as you turned the engine off so for now strike that one. Another is a failure of the cutless bearing at the end of the shaft just ahead of the prop. To check and see if the shaft is turning freely or not you would need to disconnect from the transmission and should be able to turn it by hand. At this time you can also try to start the engine. If the engine with transmission separated from the shaft does not start then you will know the problem is in either transmission or engine. If after releasing the shaft you cannot still get the transmission into neutral chances are the problem is in the transmission. If you are able to turn the gear selector into the neutral position then you should be able to turn the rear flange by hand and if does turn showing the transmission in neutral then the problem would be in the engine. If you get this far you could remove the valve cover and see if something is broken and continue to remove the cylinder head. Sometimes the transmission oil and the engine oil can give you clues as to their state of health, metal shavings and burnt oil in the transmission can point to clutch failure and metal shavings in the engine oil can point to bearings failure.
 
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Apr 5, 2009
2,774
Catalina '88 C30 tr/bs Oak Harbor, WA
The clattering you described sounds like what I had once with a bad starter clutch. It would not disengage and would start that rattle from the override.
 
Sep 29, 2018
28
Catalina 30 Annapolis
I had my yard take a look at the engine issue. They started the engine fine, heard the noise, and then the abrupt stoppage. They then turned the engine by hand and believe it to be the damper plate, as the noise was coming from the bell housing, but can't guarantee that's the issue, which I understand. The estimate to fix made me gulp a bit (pull the engine, fix, put engine back). I believe the part is around $200. I have read of others doing this replacement themselves. I am mechanically inclined, but have only done the basics in earlier years working on cars and this is my first larger boat of 2 months. A couple of questions... would it be reasonable to accomplish this without removing the engine from the boat? If so, how best to move the engine enough to separate the bell housing? Any thoughts are appreciated.
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
#1 Always kill the engine with the stop cable and then turn off the ignition switch.

#2 Do not leave the gear in forward while sailing. Neutral or reverse only. Forward can destroy the gear.

#3 As for the damper plate they can be a pita of a job with the boat in the water. Easier to pull the engine, remove the bell housing / gear and swap it out that way. The part is inexpensive, the labor is what gets expensive.
 
Apr 5, 2009
2,774
Catalina '88 C30 tr/bs Oak Harbor, WA
You get the most wear and tear on the damper plate at low rpm's in neutral. Without any load on it the jerky motion of a 3-cylinder bangs the springs a lot.
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
You get the most wear and tear on the damper plate at low rpm's in neutral. Without any load on it the jerky motion of a 3-cylinder bangs the springs a lot.
Yes, for sure, and upping the idle can definitely help.
 
Jun 7, 2016
315
Catalina C30 Warwick, RI
#3 As for the damper plate they can be a pita of a job with the boat in the water. Easier to pull the engine, remove the bell housing / gear and swap it out that way. The part is inexpensive, the labor is what gets expensive.
I can second this!

I had my engine out this past winter and replaced my damper plate. It was a nightmare to do in my garage (It also came apart in pieces, due to it being a rust ball) and it would have been next to impossible to do while in the boat.