Universal diesel multiple sudden symptoms

Skipper

Skipper

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Oct 9, 2008
1,739
Bristol 29.9 Dana Point
UPDATED POST 8/25 page 2
UPDATED AGAIN 9/20 page 3 -- it was the air cleaner.

Pretty sure I know what this is but thought I'd hit the group without diagnostic preconceptions.

Universal M18. Has always run perfect. Had always used it consistently.
However, due to job the boat has sat 3 months.
Prop has tube worms but very thin layer. Bottom cleaned 6 weeks ago.

Took it out today. Motor sluggish. Ran fine but no energy.
Would not get past 2200 rpm.
Started getting warm fast. Much quicker than years of usual. Infrared said 165 matching the gauge but water heater also went up fast to 165.
If I had continued to run it I would expect trending to overheat.
Also tiny waft of gray smoke in the engine room through the flashlight beam. Never seen this.
Back in the slip. In neutral full throttle only reached 3000. Motor reds at 3200.
Stuffing box normal temp. Elbow normal temp.
No trans issues. Normal signs and operation.
Good/usual water flow out the back.
 
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B

Benny17441

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May 24, 2004
7,131
CC 30 South Florida
Don't know about California but here in Florida a boat not in use can foul it's bottom in two weeks.
 
Skipper

Skipper

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Oct 9, 2008
1,739
Bristol 29.9 Dana Point
The bottom is fine. It's been worse without these motor symptoms.
 
jibes138

jibes138

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Jan 27, 2008
3,045
ODay 35 Beaufort, NC
Smoke in engine room could be a life or death scenario. If it is steam ok but if it is leaking engine exhaust then carbon monoxide is a very real threat. Take off the insulating wrap on your exhaust and find the leak and fix it. RPM drop could be fuel starvation, try changing filters and pump some fuel from the bottom of your tank into a mason jar to see if it is contaminated.
 
weinie

weinie

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Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
165 is normal temp.
replace fuel filters and lift pump filter.
check air filter.
smoke in engine compartment could be from crankcase breather tube. Make sure end is routed to air filter intake to get sucked in. Or change to KN filter and plug directly in.
 
31seahorse

31seahorse

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Aug 2, 2005
1,155
Pearson 33-2 & Typhoon 18 Seneca Lake
Insect nest anywhere? Impeller? Was the tubing moved (perhaps inadvertently) to cause an air block?
 
Skipper

Skipper

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Oct 9, 2008
1,739
Bristol 29.9 Dana Point
The cooling system is fine.
Fuel system spotless.

Someone mention crankcase breather. Getting close.
What would cause back pressure...

Why is the motor laboring, and not reaching rpm....
Why is she building heat fast...
- I've towed a larger boat than mine before, also the bottom has been dirtier, and never built heat like this.
 
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weinie

weinie

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Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
Definitely sounds like a fuel issue.
How do you know fuel system is spotless?
you may or may not have 4 filters.
1. Primary
2. Secondary
3. Lift pump filter
4. Screen on fuel pick up tube in fuel tank. - Should be removed.

Crankcase pressure is not an issue. But the breather hose does give off a very light smoky and smelly emanation that should go directly back in via the air filter. That is probably what you saw when it was illuminated by your flashlight. The crappy engine performance and the smoke you are seeing are just two separate issues most likely.
 
Skipper

Skipper

.
Oct 9, 2008
1,739
Bristol 29.9 Dana Point
weinie said:
Definitely sounds like a fuel issue.
How do you know fuel system is spotless?
you may or may not have 4 filters.
1. Primary
2. Secondary
3. Lift pump filter
4. Screen on fuel pick up tube in fuel tank. - Should be removed.

Crankcase pressure is not an issue. But the breather hose does give off a very light smoky and smelly emanation that should go directly back in via the air filter. That is probably what you saw when it was illuminated by your flashlight. The crappy engine performance and the smoke you are seeing are just two separate issues most likely.
Click to expand
I know it's spotless because I can see it. Racor glass.
I service the fuel system, from the tank to the injector pump, and know that it's clean.

You're forgetting the heat buildup.
:)
A lack of diesel fuel doesn't react the same way as gas.
It's not the cooling system. The motor is producing much more heat, suddenly. And it coincides with no power, and low rpm even in neutral.
....plus a waft of smoke from the crankcase...
Yes the breather is at the air intake. The setup is normal.
 
weinie

weinie

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Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
Skipper said:
I know it's spotless because I can see it. Racor glass.
How does that tell you the filter medium is clean? When was the last time you changed it?
I service the fuel system, from the tank to the injector pump, and know that it's clean.
What about the other filters and pickup tube screen?
You're forgetting the heat buildup. 165 is the low end of the normal range for that engine.
:)
A lack of diesel fuel doesn't react the same way as gas.
It's not the cooling system. The motor is producing much more heat, suddenly. And it coincides with no power, and low rpm even in neutral.
....plus a waft of smoke from the crankcase...
Yes the breather is at the air intake. The setup is normal.
Click to expand
 
S

sesmith

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Jul 1, 2010
962
Catalina 350 Lake Huron
Is the exhaust elbow free of carbon buildup? (not sure of exhaust setup on your engine but sounds like it could be a restricted exhaust)
 
LeslieTroyer

LeslieTroyer

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May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
I’m more of the prop being fouled as a major piece of this.
How low were the batteries?? If the alternator has been replaced with something bigger than 35A it can put a strain on the engine, sthe smoke could be belts.

Just alternative locations to look at.

Les
 
Skipper

Skipper

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Oct 9, 2008
1,739
Bristol 29.9 Dana Point
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. :)
 
Alan Gomes

Alan Gomes

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Nov 22, 2011
1,192
Ericson 26-2 San Pedro, CA
Skipper said:
BADA-BINGO!
Give that man a seegaar!
Click to expand
This is consistent with the observation that the engine was not making full revs in *neutral*. That pretty well takes the prop out of the equation.
 
W

wing15601

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Aug 28, 2015
190
Oday 28 St Joseph, MI
It’s very possible there are multiple problems. A very thin layer of fouling can cause the engine to lug and build up heat. The screen in your fuel tank could be clogged. You said the boat has been idle for three months and if the diesel has not been stabilized it can foul very quickly. Change the filters again, it’s cheap enough, because you have either an obstruction or an air leakin the fuel system. If the leak is at the injector you may be seeing atomized diesel.
 
jviss

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Restricted exhaust; probably blocked water injection elbow.
 
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