TWL: Unburnt fuel in exhaust
Dear Listees,
After getting so much good help on my Bimini/Curtains question, I decided to give you a real challenge:
My Krogen's Ford Lehman SP135 now produces a slick of unburnt diesel fuel from the exhaust. This developed fairly suddenly during the past season. Everyone I spoke with advised me that my injectors needed re-building. I had them removed & sent to the pros and re-installed. THIS PRODUCED NO CHANGE.
Here are the particulars:
The engine has 1800 hours. It is 15 years old. The oil has been changed every 200 hours with surgical precision, as have other engine-related maintainance tasks.
The engine starts instantly.
The engine produces a very small amount of bluish smoke while warming up, and no smoke when warm.
It operates at 180 degrees and oil pressure around 55 psi.
It is smooth and responsive throughout its' RPM range. It revs to 2800 under load & 3??? unloaded. (The tach only goes to 3000)
I generally cruise at 1800 - 2100 RPM. 1800 = @ 7knots & 2100 = @ 8.5 knots.
I've encountered no dirty fuel during the past season. The gauge on my Racor barely moved this year.
Some of the other ideas that have been offered:
Is it really fuel??? Check if it is engine oil or transmission oil leaking from the coolers. (I've checked the oil cooler by bypassing it, and that isn't the source, as the slick was still there. I'm not using much engine oil...maybe 1 quart per 50 hours operation)
Are the valves correctly adjusted? (I don't know)
Does the fuel injection pump need adjustment? (I don't know)
I would appreciate any help on how to deal with this. The diesel mechanics just seem to be guessing.
What could the cause of this be?
Thanks in advance for the help!
Craig Mudge
Krogen 42 "INTEGRITY"
Portland, Maine
cragmudge@hotmail.com
This archive was generated by hypermail 2.0b3
on Tue Nov 02 1999 - 08:34:46 EST</EM>
</EM>
</SMALL>
Craig,
I would call Bob Smith's American Diesel for their advice. Their web site is http://www.eaglesnest.net/americandiesel/ where you can get their phone number. I would not use their e-mail address. I wrote them twice via e-mail and did not receive an answer. I recently called them and received a lot of good advice from Bob Smith's son. This source probably knows more about your engine than any other source.
Herb Hoffman
My Tyme
Prairie 29
Kent Island, MD
----- Original Message -----
From: Craig Mudge
My Krogen's Ford Lehman SP135 now produces a slick of unburnt diesel fuel from the exhaust. This developed fairly suddenly during the past season. Everyone I spoke with advised me that my injectors needed re-building. I had them removed & sent to the pros and re-installed. THIS PRODUCED NO CHANGE.
snip
<!-- body="end" --> <HR> <UL> <LI><STRONG>Next message:</STRONG> Mike Tellup: "TWL: Re: Unburnt fuel in exhaust" <LI><STRONG>Previous message:</STRONG> Craig Mudge: "TWL: Unburnt fuel in exhaust" <LI><STRONG>Next in thread:</STRONG> mknott: "RE: TWL: Unburnt fuel in exhaust" </UL> <HR> <SMALL>This archive was generated by hypermail 2.0b3
on Tue Nov 02 1999 - 08:55:27 EST</EM>
</EM>
</SMALL>
Hi Craig,
----- Original Message -----
From: Craig Mudge
My Krogen's Ford Lehman SP135 now produces a slick of unburnt diesel fuel
from the exhaust.
The engine has 1800 hours. It is 15 years old. The oil has been changed
every 200 hours with >surgical precision,
As Mike Tellup suggests, it would be worthwhile to make sure that your oil
is rated for your engine. If you have a manual for the engine it should tell
you what API rating you need. You probably need a CD, CE, or CF and most
commonly available engine oils meet those specs. I would recommend a 15w40
while the estimable Mr. Smith at American Diesel prefers a straight 30.
The engine produces a very small amount of bluish smoke while warming up,
and no smoke when >warm.
Blue smoke indicates that you are burning (or trying to burn) lube oil. This
could be getting by the rings or the valve guides but the fact that it stops
during warm-up implies that it's just a bit of seepage past the valve guides
from whatever oil accumulation was left on top of the head at last shut
down. A similar phenomenon sometimes happens if you idle the engine long
enough for its temperature to drop.
Is it really fuel??? Check if it is engine oil or transmission oil leaking
from the coolers. (I've checked >the oil cooler by bypassing it, and that
isn't the source, as the slick was still there. I'm not using much >engine
oil...maybe 1 quart per 50 hours operation)
It probably isn't fuel, although there is no feasible way of checking
directly (a sheen is a sheen). If you are using a quart every 50 hours and
you don't have oil in the bilge the next most likely exit for that oil is
out the exhaust by way of the combustion chamber. Keep in mind that a really
small amount of oil can make a really big slick.
As a way to collect more information, try this: The next time you go out run
the boat long enough to get it completely up to operating temperature
(minimum 30 minutes at cruising speed), then find some calm water and stop
(engine at idle) and immediately check for a sheen. If there's no sheen or a
significant reduction then you probably should just live with it until it's
time to do something else to the engine. If the same level of oil is still
in evidence then it may be time to think about rings, valves, guides, etc.
What could the cause of this be?
Even though 1800 hours isn't necessarily a lot, 15 years is quite a long
time to be sitting in an engine room in a marina. It's not totally
unreasonable to expect some wear in that time.
Deductively yours,
Alex