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Universal diesel multiple sudden symptoms

Aug 4, 2018
55
Pearson Yachts 39-II Punta Gorda, FL
I know 165 is normal.
I said it built to 165 way too fast.
Like 4 times too fast.
And I said the water heater built too fast too. It would have trended to overheat had I let it run under load like I was, after the water heater obsorbed the initial heat.

Trust me. Intimate with the boat for years. Fuel and cooling systems are fine. :)
Skipper, disregarding the reduced power and the wisp of smoke or steam you observed: Given your certainty that the raw water side of the cooling system is working fine and that your exhaust is not restricted the rapid rise in coolant temperature indicates poor heat exchange from coolant to raw water - most likely your heat exchanger on the engine coolant side, or the coolant hoses, or the thermostat. Less likely would be the engine's coolant pump not providing flow. There's many ways to inspect or test for blockage and flow, at the return from exchanger to the block for example.

Sorry did not see your HX post #29. Did your test of that include actual coolant flow out of the exchanger with the engine warm - i.e. did you include thermostat opening and coolant pump performance?
 
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jviss

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Feb 5, 2004
4,627
Tartan 3800 Westport, MA
If I had continued to run it I would expect trending to overheat.
It never actually overheated.
Also tiny waft of gray smoke in the engine room through the flashlight beam. Never seen this.
Probably unrelated.
Back in the slip. In neutral full throttle only reached 3000. Motor reds at 3200.
That's not that far off from max speed of 3200.
No trans issues. Normal signs and operation.
How do you know? Any temp readings? Examine fluid?

Based on reading this entire thread, and assuming the OP is correct in his observations and assertions, I suspect an accessory or transmission problem; that a failing bearing or other component is causing a great deal of drag.

These can mostly be isolated by removing the belt, and then by turning the engine crankshaft with a wrench (pull the compression release); and turning the prop shaft by hand with the transmission in neutral (though not conclusively, since you can't separately get to the input side of the transmission).
 
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Likes: Pearson 39-II
Oct 9, 2008
1,733
Bristol 29.9 Dana Point
It was the damned air cleaner.

The design is not good. See pics. There is only one small inlet. That inlet is covered by the foam element. No reason for foam all around, could have just had foam over the inlet, same effect. Clogging.
As the motor gets older, a bit more oil comes out the breather. That oil clogs the element. If you rem the element it looks fine, but upon closer inspection the part at the inlet is clogged.
That poor little motor was trying to push a 10k LB boat through the water while trying to suck enough air to do so through 1/2 square inch of clogged foam.
I put in a KN air cleaner(pic). Motor now revs willingly, pushes boat to 6.2 knots at WOT, and cool running to spec.
The hilarious part is that since I had removed the exhaust system and HX, I had decided to do a few maint items, and ran into misery with some hoses.
Maint items: Cleaned out and painted the manifold, tested the elbow, rem and cleaned the HX - dumped out the old loose zinc pencils, new coolant, gaskets, etc.
Aaand... replaced the hoses from the HX to the water heater. Turns out the HX fittings are 7/8 and the heater is 3/4. Those Bristol guys had stretched the hoses on. But no way on god's blue earth were the new 3/4 hoses going on. Oil, Vaseline, heat, brute force, lot of cussing. No way. (Pic).
And there are no 7/8 adapters. I looked.
Except... One. Finally McGyvered that old extra elbow from the alternator bracket upgrade. To my loving surprise, it's 3/4 to 7/8. Never throw anything away. And the elbow actually routed the hose better.

So the end is that while I got some maint items done, it was 3 days (combined) of misery, and the air cleaner was the original culprit. 10 minutes to install.

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Jun 11, 2004
1,220
Oday 31 Redondo Beach
It was the damned air cleaner.
Awesome! I've had a K&N air cleaner on my M18 for some time. I also have a blowby (breather) filter and route the filtered blowby directly through the air filter to the engine.
 
Oct 9, 2008
1,733
Bristol 29.9 Dana Point
Awesome! I've had a K&N air cleaner on my M18 for some time. I also have a blowby (breather) filter and route the filtered blowby directly through the air filter to the engine.
I just zip tied the breather to rest on top of the air cleaner - picture above.
Works perfect.
 
Aug 22, 2017
1,608
Hunter 26.5 West Palm Beach
An air restriction makes perfect sense. Reduced air will cause a rich mixture. When diesels run rich, they run extra hot, which is the opposite of a gas engine. Gas engines run hot when lean.

The excess heat either had to be rich fuel condition or poor cooling system operation. The loss of power had to be either excess mechanical load (bad bearing, fouled prop, mucked up trans, etc) or a fuel/air problem or a compression problem or a timing problem.I think that's all there is in that system.

I have seen vacuum gauges on the intakes of some diesels, to monitor the condition of the air filter. It does not seem to be a common practice on sailboats, but perhaps the should be?

Thanks for posting. This thread brings to light a lot of great information.
 

cjm1

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Jul 10, 2013
40
custom Herreshoff 33 sloop Lake Charlevoix
I have a 5432 universal and did not like the idea of that small air filter. It is a kabota engine used in farm tractors and they use a much more effective air filter. As far as the breather being fed into the air filter, my thinking is a bad idea. I vent it overboard in a thru hull fitting just above the waterline on the transom. About 1100 hours on engine and no problems. It is a great engine..
 
Feb 27, 2005
183
Hunter 33.5 Missouri
We have an M18 and I would like to install a K&N filter. Can you provide the particular part number for either of the filters that have been mention in this discussion.
 
Jun 11, 2004
1,220
Oday 31 Redondo Beach
We have an M18 and I would like to install a K&N filter. Can you provide the particular part number for either of the filters that have been mention in this discussion.
I'll try to check next time I'm at the boat.
 
Jan 7, 2011
2,913
Oday 322 East Chicago, IN
How about a plugged fuel vent? If the critters made a nest in your vent, and you are pulling a vacuum in your fuel tank, won’t take long to be starved for fuel.

Greg
 
Jul 5, 2011
598
Oday 28 Madison, CT
Thanks for all this. I don't replace my air filter every year, but will be checking and replacing soon!
 
Jun 11, 2004
1,220
Oday 31 Redondo Beach
We have an M18 and I would like to install a K&N filter. Can you provide the particular part number for either of the filters that have been mention in this discussion.
This is what I put on my M-18.

K&N RE-0240 Universal Clamp-On Air Filter: Round Tapered; 1.5 in (38 mm) Flange ID; 3.5 in (89 mm) Height; 3 in (76 mm) Base; 3.5 in (89 mm) Top

I route my filtered blowby through that hole in the top but if you don't want that I'm sure you can find another K&N filter of the same or similar size to fit. That would probably be the RU-0160
 
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Feb 26, 2004
21,951
Catalina 34 224 Maple Bay, BC, Canada
We have an M18 and I would like to install a K&N filter. Can you provide the particular part number for either of the filters that have been mention in this discussion.
May be in these, for an M25. If I were in your shoes, I'd just measure the air intake diameter before ordering something based on someone else's suggestion. Good luck.

Breather Hose 101 (w/ K&N Filter Pictures from Rick Allen)

http://c34.org/bbs/index.php/topic,8875.msg63915.html#msg63915

and Noah's: http://c34.org/bbs/index.php/topic,8858.msg64297.html#msg64297
 
Jun 11, 2004
1,220
Oday 31 Redondo Beach
RU-0370. See pic.
This is the low profile round version.
There are cone, oval etc avail too.
View attachment 157200
Interesting. That one has a 1.75" flange ID. The one I use has a 1.5" flange ID.

As Stu said, you should measure your intake diameter and make sure you get a filter to fit. The K&N website has the ability to filter by several criteria.