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Old 08-17-2012, 04:33 PM   #81
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Any other Lehman's out there with EGT's? If so, it would be interesting to know what you're running.
It is important to know where the temperature is taken if comparisons are to be made.
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Old 08-17-2012, 04:45 PM   #82
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Our EGT probes are mounted in the exhaust elbows just aft of the connection to the exhaust manifold and prior to the water injection point. Our EGT sensors and gauge are by ISSPRO.

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Old 08-21-2012, 12:02 PM   #83
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This summer the after cooler on one of our Perkins Sabres developed a leak allowing sea water into the induction air. I bypassed the after cooler and ran about 1000 miles with no ill effects on either EGT or a variety of engine temps as measured with an IR gun. On advice of the designer I limited max RPM to an EGT of 600 F or about 80% of full rated load equating to 2000 RPM. 2000 RPM I never hit anyway with normal cruise about 1750 RPM and 400 F EGT.

This issue caused me to once again visit the belief that unless a marine engine can achieve max rated RPM without over heating, something is amiss whether in engine health or prop size. For sure, one of the boxes to be checked when buying or selling is "Max rated RPM achieved OK?"

In my pre-retirement years, the last big diesels I bought were 4000 HP and rated for full RPM at 15,000 feet for a 30 minute climb out of an open pit. This is how the engine designers have built most diesels for decades if not 70+ years or more.

So my thoughts, run them hard now and then to assess engine well being. The next owner sure as heck will prior to finalizing a purchase decision.
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Old 08-21-2012, 12:38 PM   #84
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When I repowered I made a big deal of getting sea water off the engine completely. Never regretted it.
Wish you were down the street so we could swap sea stories Tom.
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Old 08-21-2012, 04:57 PM   #85
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Originally Posted by sunchaser View Post
This summer the after cooler on one of our Perkins Sabres developed a leak allowing sea water into the induction air. I bypassed the after cooler and ran about 1000 miles with no ill effects on either EGT or a variety of engine temps as measured with an IR gun.
___________________________________

Have you had any issues with the engine since leaking salt water through the air intake?

I had a dripping exhaust elbow joint over the air intake, 6.354 n/a, that went undetected for several weeks on a trip. After the joint was repaired, everything was fine for a while. Then we started hearing a slight compression hiss at idle. Thinking it was a head gasket, we pulled the head and found two of the hardened valve seats on the intake side had severe pitting.

Anyway something to watch for.
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Old 08-21-2012, 08:08 PM   #86
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Thanks Marin. That is one for sure.

So anyone with an FL120 should follow your advice.

It seems that it is going to be an as per engine.

The Cat dealer is of a mind that it is a good thing to do once in a while.

Any others?

SD
SD, we don't run up to WOT because we can achieve a nice hot EGT at around 1750 rpm, and while there may be a reason to put a greater load on the engine, I don't know what that reason would be. So we cruise around 1375 - 1400 rpm at 550 degrees EGT (out), which probably means around 700-750 degrees inlet temperature, and 775 to 800 degrees (out) and probably 1100 degrees inlet temperature at 1750 rpm. I get a little visible smoke when I first spool up (which I do every 4 hours or so for 15 minutes), but that dissipates to being almost invisible after 5 minutes or so of loading. I don't know if this is the best way to manage the engine, but it seems to match what most experts recommend.
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Old 08-21-2012, 08:47 PM   #87
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Talking to my local commerical guys, They refered me to a manual one of them had with the specs that the perkins should operate at 80% of max rated RPM during use. I know that all our military equipment " diesel " crank and after about 45 seconds runs up to almost WOT. Some times for 10 days at a time to provide power for the FOB's. they would fuel them and about every 10 days they would shut them down check coolant, Check the oil, Take a sample of the oil, Service it if hours were in range then fire them up again. i Never seen any of them fail running WOT one was at a FOB i worked at on two deployments so it had been there over 3 years doing its job. So i guess it's all in what the MFG says about the 80% range .
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Old 08-22-2012, 12:11 AM   #88
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honeybadger,
Are you sure they spec'ed 80% of rpm? That would seem a dangerous thing for them to do as many boats are'nt propped right. The load on an overpropped boat would likely be WAY overloaded at 80% rpm. Also 80% of rated rpm on a correctly propped boat is about 50% engine load. This is a very low load for a max continuous rating. A 37 Plymouth could probably do that.
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Old 08-22-2012, 01:43 AM   #89
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Don't forget that he makes a living selling engine parts.

A freshly washed car always seems to run a little better too.

Don't start rumors now.
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Old 08-22-2012, 02:05 AM   #90
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The Yanmar FAQ area on the web says this:
Q- What is the definition of a LDC (Light Duty Commercial) application?


A- Any engine used in a revenue producing, government service or rental use is considered a non-recreational craft application and is not covered by the Yanmar Recreational Limited Warranty policy. Rental use is defined as a vessel used for pleasure charter, typically sailboats, sailing catamarans, power catamarans and trawlers. For an engine to be considered for a Light Duty Commercial application it must fall within the following guidelines:

• Engine is operated at maximum output for less than 5% of total operation hours.
• Standard operation is at less than 90% of the maximum output RPM.
• Wide open throttle RPM’s, under load, must reach rated speed in any operating condition. post rpm is max 3000 max load ,Continuous rating rpm listed as 2900. So as i say Who knows ??
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Old 08-23-2012, 02:14 PM   #91
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the last big diesels I bought were 4000 HP and rated for full RPM at 15,000 feet for a 30 minute climb out of an open pit. This is how the engine designers have built most diesels for decades if not 70+ years or more.

These were industrial duty engines.

Many "trawlers" have lawn implement or converted taxi engines , a far far different base engine .

IF there is NO MFG 24/7 power rating , caution is the watchword

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