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Old 07-31-2016, 08:07 AM   #21
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Hello Guys,
Thanks to all who recently posted.

Chrisjs, I did change impeller. The old one looked fine but at least it is now brand new.

David, Thank you for expanding on Ski's posting. That helped a lot.

Cardude01, Yup.

FF, Murphy huh? I'll check that out as well. Sounds good as ours is a pleasure boat with just me at the helm but we all need breaks on longer legs.

Thanks again guys!
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Old 07-31-2016, 10:52 AM   #22
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You changed the impeller but what you dont know on a previously owned boat is if all old impeller and zinc parts were removed in the past. When I got my boat I opened the heat exchanger and found several broken off zincs plugging the lower part of the cooler. the engine was not yet running hot but I was just checking for sloppy previous work. Impeller parts will often collect at the first downstream location from the pump. They will some times move so they dont always block tubes.

I would not change to 160 stat. You want the engine to run warmer at low loads in winter when water is colder. In my experience stats are fully open a few degrees above their rating. Some Cummins use two stats in parallel. I had on sticky that caused hoter than normal running at first then the temp dropped when it finally opened. The rubbing marks on the one stat were obvious when I took them out.

To find oil galley look for the current oil sender switch. on some cummins it is on the port side down low. you will probably see a tube cast in the block with pipe plugs along it. Any of those can be used for oil pressure senders.

My point of all the above is that with a new to you boat i would open and inspect everything before changing anything though for the longer term the additional temp monitoring is a good idea. I think you are analyzing the issues well but I tend to think the original system should work as designed until everything else is ruled out absolutely.

Sudden overheating can quickly become catastrophic on hard running engines so the exhaust monitor is a great idea because that provides the earliest warning except for exhaust sound. learn what your boat sounds like and if the exhaust starts to bark shut it down.
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Old 07-31-2016, 12:22 PM   #23
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The alarms on our engines are set at 200-205 degrees. Thermostats are 175. I've noticed that the aftermarket kits that place a thermocouple around the exhaust pipe have come down in price.

As a side note, there's a Grand Banks East Bay 49 parked next to us with a burned out exhaust system on one of the QSC8.3 Cummins. Owner forgot to open the seacock for raw water pump. Don't know if the engine survived without damage as the Cummins mechanic can't/won't start it without the exhaust system. Of interest to me was that the primary failure was at input pipe on the muffler. Looks like the bonding agent (epoxy?) between the pipe and the muffler body melted away. Made a mess of the engine compartment with black soot everywhere. Wonder what insurance companies say about an operator induced failure like this...
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Old 07-31-2016, 01:58 PM   #24
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"FF, Murphy huh? I'll check that out as well. Sounds good as ours is a pleasure boat with just me at the helm but we all need breaks on longer legs."

The switchgauges can be purchased with a system to ( when desired) just ring an alarm or automatically secure the engine if a setting is reached.



The shut down can be electronic or a pulled to arm spring released by a hot shot battery , so even with a total electric failure the system can operate.


The gauges are mechanical so it takes a bit of planning to order , and minor skill to install .


Gauges | Murphy by Enovation Controls


Murphy by Enovation Controls › Products


Murphy is known for its gauges, and there's a good reason why. They're durable and dependable. They're highly accurate and long-lasting. We didn't make ...



Mechanical Gauges (Pressure) | Murphy by Enovation Controls

www.fwmurphy.com/products/gages/pressure




The 2- and 2.5-inch (51 and 64 mm) dial pressure Swichgage instrument with a polycarbonate case for environmental sealing. 45APE. The 4.5-inch (114 MM) ...
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Old 07-31-2016, 02:10 PM   #25
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Tony Athens is the moderator of the Cummins forum at boatdiesel.com and has this company Cummins Marine Diesel Repower Specialists. He knows all things Cummins and has mods or upgrades for many issues. I'd ask his advise.
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Old 07-31-2016, 03:15 PM   #26
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Tony Athens is the moderator of the Cummins forum at boatdiesel.com and has this company Cummins Marine Diesel Repower Specialists. He knows all things Cummins and has mods or upgrades for many issues. I'd ask his advise.
I have a 1989 210 HP 6BT. My engine runs at about the same temps as you have indicated. I have 6 years of experience with the boat and have used SBMAR, and Boat Diesel several times. If you research the site you will find that the old 6BT cooling system have very little margin. My boat won't handle WOT more than 15 minutes. Temp climb to the alarm. My alarm goes off at 205. I can run at 2200 RPM all day and the temps are around 190. I run at 1500 RPM and about 180F. Anything above that is just inefficient fuel burn. I have made a few of the modifications suggested by Tony Athens to increase flow.
You didn't mention the years of your engines. Cummins improved the design on units newer than mine.
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Old 07-31-2016, 10:57 PM   #27
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If you go to Boatdiesel and look in the ARTICLES section, L.H. side menu on the main screen, you will find Tony's Tips. look them up and I'll bet you will find all kinds of info for you to use. Then spend some more time reading all the other stuff because there are a lot of squiffy installations.


Go to his site sbmar.com Yes he sells stuff, good stuff. You can pick up a huge amount of info by reading. He has made it all available for nothing.

Even if you do not follow all of it then you will be forewarned if a problem comes up.
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Old 07-31-2016, 11:18 PM   #28
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Semi-planing, FF, Sean9c, fryedaze,
Thank you all.


It's a bit overwhelming but I really appreciate all the input and willingness to share experiences to help a " new guy".
You're awesome.

fryedaze: my Cummins is a year 2000 with 816 hours.

I've come to the conclusion that some independence and redundant sources of temperature information plus a bit of work to insure what I have works correctly before making any changes is the most prudent course.
Thanks again!
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Old 07-31-2016, 11:22 PM   #29
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C lectric,
Thank you.
There's great information " out there".
I really appreciate the guidance.
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Old 08-01-2016, 07:00 AM   #30
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"My boat won't handle WOT more than 15 minutes."

That is usually all thats required to get a vehicle up a big hill.
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Old 08-01-2016, 09:25 AM   #31
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IMO many older boats were built with exhaust sized for lower powered engines than become options later. I see some mighty small exhaust ports in the yard. If those were connected to a turboed engine they may just be too small and indicate the raw water system may be undersized.

I dont think an engine should get too hot at wot regardless of how long it is run. To me that indicates something not right.
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Old 08-01-2016, 10:20 AM   #32
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I've come to the conclusion that some independence and redundant sources of temperature information plus a bit of work to insure what I have works correctly before making any changes is the most prudent course.
Thanks again!
I think you have come to the correct conclusion. Also, your alarm should be set to 203 as per Cummins and not 190. As everyone has stated, 190 is not particularly "alarming" as far as temp goes. You just don't want it to go any higher than that.

I have 330Bs in my boat and have had similar issues. I do not know the "flow diagram" of your exhaust system but I would think the first spot your impeller vanes would get hung up is your transmission cooler since you do not have an aftercooler.

As far as Murphy Gauges go...I did purchase one. They are mechanical extremely accurate gauges. I used it as a compliment to make absolutely sure all of my other indications were correct(OEM gauge and IR gun). I screwed it into the port where the temp sender is. And that confirmed to me that my engine was NOT running as hot as indicated.

My issue with IR guns is that you can hit one spot(ie near temp sender) and it show 178. Then move it a millimeter and it shows 243. That is a just an example but you can basically get whatever temp you want out of it based on where you point it. I guess my point here is I do not get a lot of confidence out of the reading of an IR gun. My most consistent temps are on the pipe leading to thermostat and on the expansion tank. I was told to hit the beam at the head just right next to the sender. I cannot get a consistent reading there.

Anyway, a Murphy gauge is cheap and easy to use and will answer a lot of questions for you....mainly is your gauge correct.

I even went so far as getting another heat exchanger(I am not advocating this....only exemplifying how far I was willing to go to get to the bottom of the issue). It is not installed but I was damn curious....$860 curious....and that is not OEM parts. The OEM Cummins part was something like $1800. A Company called Mr. Cool sells them cheaper and they are made by the same people....Sendure and...I forgot the name of the other one. Very excellent customer service people at Mr. Cool.

So Ski and David, I have a question. When I took the sending unit out of the hole and screwed in the Murphy Gauge, was I also disconnecting the alarm??? IOW, is the alarm on the same wiring/circuit as the gauge??? I assumed it was and acted accordingly. ANd I never saw anything over 185.
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Old 08-01-2016, 01:50 PM   #33
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Bayview, Thanks very interesting point on exhaust sized for lower powered engine.
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Old 08-01-2016, 01:58 PM   #34
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Baker,
Thank you. Having a very accurate mechanical gauge does seem to be an excellent, inexpensive and simple "add-on".

I do have a question about your Murphy gauge, you said..."I screwed it into the port where the temp sender is. And that confirmed to me that my engine was NOT running as hot as indicated."

Did you relocate the temperature sender so that you still have working temperature gauge(s) on the helm(s)?
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Old 08-01-2016, 02:05 PM   #35
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Baker- If your alarm system uses the Cummins pcb at the helm and if you removed the electric gauge sender from the engine, yes you have disabled your high temp alarm.

There should be two port on front right of cyl head so you can keep the sender and the murphy gauge at the same time.
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Old 08-01-2016, 02:21 PM   #36
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Baker,
Thank you. Having a very accurate mechanical gauge does seem to be an excellent, inexpensive and simple "add-on".

I do have a question about your Murphy gauge, you said..."I screwed it into the port where the temp sender is. And that confirmed to me that my engine was NOT running as hot as indicated."

Did you relocate the temperature sender so that you still have working temperature gauge(s) on the helm(s)?
It was a temporary set up to test indications. Murphy gauges use a "diaphragm" tube with gas in it. The expansion of the gas moves the needle on the gauge. I tell you this because there is a limit to how long that diaphragm tube can be. That limit for a Cummins B engine is 20 feet I believe...since the temp sender port is 1/4 inch...both figures going by memory. So if you want to have a permanent murphy panel, they have to be within 20 feet of the engine...and that tube cannot be bent at a very sharp angle. Once it is kinked, it will not work properly. I have a flybridge helm and not sure 20 feet is enough.

But back to your question, it was temporary and had no helm instruments while this test was in progress.
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Old 08-01-2016, 02:21 PM   #37
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Baker- If your alarm system uses the Cummins pcb at the helm and if you removed the electric gauge sender from the engine, yes you have disabled your high temp alarm.

There should be two port on front right of cyl head so you can keep the sender and the murphy gauge at the same time.
Ok thanks. That is what I thought.
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Old 08-01-2016, 02:44 PM   #38
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Nice.
Thank you Baker and Ski.
I noticed that spare, plugged, port just to the right of the sender next to a bracket (for lifting the engine I guess). It's appears to be almost an inch across.
Two questions come to mind.

1. do you need an adapter to install a Murphy gauge there since the hole is bigger than the sender hole (or at least it seems so to me)?
2. Are there other spare ports, say, to install a switch for a separate alarm?
Triple redundancy, all different.
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Old 08-01-2016, 03:03 PM   #39
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Nice.


1. do you need an adapter to install a Murphy gauge there since the hole is bigger than the sender hole (or at least it seems so to me)?
2. Are there other spare ports, say, to install a switch for a separate alarm?
Triple redundancy, all different.
I installed mine where the original sender is. So if it is a different size, you will need a different sized murphy gauge adapter. With that said, the one I have came with a few different adapters....and you likely could find the one you need at a hardware store if it is not supplied by Murphy.
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Old 08-01-2016, 07:43 PM   #40
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Thanks Baker,
I noticed Seaboard Marine has a VDO 120- 250 sender with a 205 switch.
Maybe by replacing my current sender with this one allows me to keep my helm gauges and maybe even the current 190 over temperature light as an "early warning". Then I disconnect the 190 buzzer feature on the circuit board. Next I wire a new buzzer to the 205 switch on the new sender.
I could install a Murphy mechanical gauge to the extra port.
(BTW: I appreciate the info. on the limitations of the Murphy gauge. I think I might be able to mount it on the flybridge without any kinks in the run.)

See any errors in my thinking? I'm new to this and learning so, please, don't hold back.
Thoughts, input anyone?

Thanks again!
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