Hi Guys, well here we go again, last fall my engine wouldn't start unless I fogged it with starting fluid, I know not a good idea, and when I shut the engine off, it would start with no problem after that. I replaced all three glow plugs this winter and done the solenoid upgrade, here is the problem, all 3 new glow plugs failed, I have bench tested them and can't get any heat out of them, the first time I tried to start my engine, it kind of galloped along until it finally started. I did get a voltage drop which got progressively weaker until now there is no voltage drop.
guys I only got one bad start with the new glow plugs, what's going on that I destroy my glow plugs. I have 14 volts to each one, but they just won't heat up, and when I remove them, they are wet with fuel.
I have put a MOM switch in the engine compartment so I know the solenoid is getting voltage to the plugs, I get nothing at the plug until I activate the solenoid, then get 14 volts but no heat.
I have been trying to start while plugged into shore power. I now know that is a no-no, but I do believe since I got the boat and I was real dumb then, that's the way I always started the boat and didn't destroy the plugs for 2 seasons anyway.
in a test, If I put the small threaded end (where the wire goes) on the battery positive, and the the body of the plug (where it enters the engine) on the negative side of the battery, it should heat up right? well none of the 3 new ones heat up. I have read all the posts from the archives and didn't come up with a answer on destroying new glow plugs almost instantly. I will order 3 more new ones, but am understandably nervous about putting them in. Any Ideas? will 14 volts while plugged in to shore power wipe out the plugs right away? could I have gotten 3 new bad ones? Thanks guys Bob
It is probably safer to check the glow plugs resistance than trying to manually attach to a battery. Can't tell you what it is, should be high, but not infinite or zero. I don't think 14v should hurt them either, they seem to be pretty bulletproof. Double check all you wiring, including the ground cables to ensure you are not focusing on a symptom rather than the cause.
Sorry not much help, this is a strange one.
I think the resistance should be between 3-7 ohms, not much, which is why they draw so much current. I assume you are aware that these are Kubota parts, and are a fraction of the cost compared to Universal.
Bob - I think it's probably the high voltage from the shore power charger. That's what I attributed it to on my boat. You shold be able to find replacements for less than $10 each at a Kubota dealer or online. I wish I had the NGK part number handy for you.
Craig
I typed in NGK glow plugs in the search box and found this: http://c34.org/bbs/index.php/topic,3347.msg20998.html#msg20998
I, too, originally suspected "high" voltage, but it would do you well to read the box and labels on the glow plugs which should indicate a range of voltages. I don't think it's that, but whadda I know...
There have been reports of people starting their engines while their shorepower charger is still on. It really doesn't do any harm, although I guess the chances of leaving the dock with the plug still in could be higher... The downside is that you don't know, until "you get out there Kitty," is if your reserve or house banks work and can start your engine.
I can comment from recent experience that if your batteries are low/dead, the motor will not start even if connected to shore power :cry4`. It may just be the brand of charger that I have. I hadn't heard about an issue of starting the motor with shore power still attached. What is the problem with doing so? :think
The part number for NGK is Y103V I called carquest and have 3 coming at $8.31 apiece, I called the tech people at NGK and a very knowledgeable fellow reminded me the plugs are rated at 10.5 volts, which is stamped on the plug. He said in all likely hood, the 14 volts burned out the plugs, he said even 12 volts from the battery is bad on the plug, and encouraged me to install a resister in the line limiting the voltage to 10.5 volts, now I have had my boat for 3 years and never had this problem with burning out previous NGK plugs, I wonder if the solenoid upgrade gives me too much honest voltage, (maybe the long #10 wire knocked some of the voltage down)
I do admit with the upgrade, for the first time, I held the plugs on for a long time, 40 seconds, the plug never felt even remotely warm, the tester was on showing 14 volts all the time. thanks for your input, it is highly appreciated. Bob
Another idea, when I bench test the new glow plugs and ascertain they are working, I will then connect them to the wiring at the engine and before installing them in there perspective holes, I will again check them on the boat by grounding the plug, activate the power, to visually see if they are glowing, then I will know for sure weather it is something else or not.
Kind of wierd, "how hard can it be?" I mean unless I am missing something, the wire goes from the starter solenoid, to the switch, then back down to the plug, or in this case, the small nut on the solenoid, then to the plug. I don't think that there is a resister hidden in the system that went out, and why would (factory) install plugs rated at 10.5 volts with a 12 volt system. without a resistor of some sort. I do believe the old plugs were factory as they were painted same brown color as engine. I don't know guys, just all seems strange. Thanks again Bob
Quote from: pogmusic on May 15, 2009, 07:24:38 AM
I hadn't heard about an issue of starting the motor with shore power still attached. What is the problem with doing so?
The issue is that you have two sources of charging happening at the same time once the engine starts: the shorepower charger and the alternator. Many people over the years have done this, unknowingly, without harm. For those with solar panels, the panels charge when the engine is running, too, so two charging sources, in and of themselves, is not necessarily harmful.
It just doesn't make any sense, personally, to me, to have your shorepower charger on when you start your engine. If you're starting your engine, it means you're ready to leave the dock, so why start the engine before you disconnect from shorepower? Some like to "idle" their engines to "warm 'em up" before they leave the dock. This is one of the worst things you can do to a diesel engine.
KISS: turn your charger off, turn off the power at the dock, disconnect your cord, and then start your engine.
Quote from: Bobg on May 15, 2009, 07:42:29 AM
The part number for NGK is Y103V ...the plugs are rated at 10.5 volts, which is stamped on the plug. He said in all likely hood, the 14 volts burned out the plugs, he said even 12 volts from the battery is bad on the plug, and encouraged me to install a resister in the line limiting the voltage to 10.5 volts...
Bob, I must admit that after 11 years here, this is the very first I've ever heard of this, and some of us have had their boats for twice as long as I have and I look forward to their input.
Have you checked with a Kubota tractor engine dealer or with Universal (www.marinedieseldirect.com, Torresen, etc.) about this alleged "voltage to glow plugs" issue?
Expanding on the www.marinedieseldirect.com, here are a few other links there:
This is the general parts list: http://shop.torresen.com/marine_diesel_direct/Universal/index.php?p=include&contentsection=universal&contentname=engine&engine=M25
This goes to the glow plugs: http://shop.torresen.com/marine_diesel_direct/Universal/index.php?p=details&mfc=Universal&sku=299685
These are for M25 engines, find your engine and search away.
Stu, I havn't talked to kubota or universal yet, but good idea, I bought the first set of plugs from a kubota dealer, using the universal part number, I got NGK Y1030v, same as the ones in my engine. I did notice the web site you provided and the plugs were 71 dollars apiece. too much for my blood. will go to the boat next wednesday and see what happens. I did the Ohm test and they are certainly shot. thank you and will provide a update next week. also I will install a 1/4 inch test lite you suggested. Bob
Bob : Guess I'm confused and like Stu I haven't heard of this problem like this in the past 20+ years.
If your shore power is OFF (which it should be!!) I'm not too sure how you're getting 14V to the glow plugs. I usually see a 2 to 3 Voltage drop when I engage the glow plugs from a full battery bank of NMT 13 volts?? :think
Ron,
Interesting unintended consequence of having your shorepower charger plugged in when you start your engine.
You could burn the glow plugs out!
I just KNEW there was another reason not to do that... :sick
Wow! Learn something every day. I had my Cat 30 for 18 years and my Cat 34 for 7 years and would start my engine with the shore power on many times. When I just want to run it in the slip, the shore power is on. Haven't had a problem yet .... never saw any warning about over voltage on glow plugs. Is it in a manual that I overlooked? Or am I just lucky?
Ron, I only have 14 volts when the shore power is on, like I said the plugs are rated for 10.3v, stamped right on the plug, when I talked to the NGK service rep, he was adamant on not holding the plugs on for extended time, and that the 14 volts going to the plug was a definate no-no, maybe all those years I was simply lucky I didn't burn them out quicker. I asked him "off the record" if he thought the plugs would take more than the 10.3V, he said maybe for a short period of time, few seconds, but would not recommend it, he told me to go to radio shack and get a resistor to limit voltage to 10.3 volts. Anyway, I am going to contact Kabuto and find out why they put a 10.3volt plug in a 12 volt system without a resistor of some sort, unless there is one hidden in the line somewhere and I am not aware of it. Going to the boat wed and see whats up. will post my conversation with a kubota or universal tech rep. Thanks Guys Bob
I wonder if the "solenoid upgrade" could increase the likeliehood of burning out" the plugs if shore power is connected. Not being an electrical guru, I have no idea. I do know that the upgrade does increase the power (current and volts?) to the plugs. Perhaps this coupled with a jolt of shore power is the villain.
"shore" enough? ,
Ken
I have started the engine with the shorepower connected for 18 years, never had a problem and still have the original glow plugs!!
Enough said! There is obviosly something wrong with the changes made!!
Guys, Susan and D. Gill : It's not the fact that the shore power is ON, it's the fact that the AC battery charger is ON !!!!
Many times I start the engine while plugged into shore power, but I turn the AC battery charger off first!!
Bob try it with the AC battery charge OFF and I believe you'll be OK. A thought
Wouldn't just shutting off the AC Master switch shut down shore power to the glow plugs? I have also started mine with shore power on, with 2 Cat 30's over 20 years and my Cat 34 for the last 4+ years. The diver that cleans the bottom every month said to start the engine at least once a week and run in gear to clear the barnacles out of the cutlass bearing or I will have to replace it every haul. The water here is polluted, brackish and full of bad stuff that likes to hide in bearing...it's paradise man...
In regards to why Kubota used 10.5 volt glow plugs, you have to understand how these engines were originally designed to be used. The Universal Marine engines are derivatives of industrial engines that are started with minimal capacity batteries. The voltage at the glow plugs will quickly drop to 10.5 when you engage the starter. With a 12 volt battery, the glow plugs are only exposed to a 10% overvoltage condition, not a significantly excessive amount. A 14 volt supply would mean 33% overvoltage condition, which could possibly be significant at high duty cycle times.
Now in the marine environment, battery capacity can easily exceed 200Ah and with the addition of glow plug solenoids, voltages stay much closer to 12 volts during the entire start cycle.
Assuming 10.5 volts at the glow plug and a 3 ohm resistance, the glow plug is putting out about 1.4 watt-hours if heat in a 15 second activation, inceasing the voltage to 12 volts increases wattage to 1.8 watt-hours. If you are applying 14 volts, wattage is increased to 2.45 watt-hours.
To reduce glow plug burnout under higher voltage conditions, you must adjust duty time accordingly. If you assume 15 seconds is sufficient for preheating, then if you are putting 12 volts to the glow plugs the duty time should be reduced to 11.5 seconds and at 14 volts you only need ~8.5 seconds.
If an earlier comment of 40 second duty cycle was at 14 volts, the equivalent 10.5 volt cycle would have been over 70 seconds.
Adjustment of duty time would be preferable to installing a dropping resistor. Assuming your battery and engine wiring is capable of delivering very near 12 volts and you want to keep glow plug voltages at 10.5 volts you would need a resistor 0.15 ohm 25 Watt resistor for a 3 cylinder engine and 0.11 ohm 25 watt resistor for a four cylinder engine. The installation of a resistor would degrade performance when starting with a weak battery and would not drop the voltage properly should one or more glow plugs be inoperative or internally degraded. Adjustment of glow plug timing to voltage conditions would make for more consistent staring and improved plug life.
Steve wrote:-----and with the addition of glow plug solenoids, voltages stay much closer to 12 volts during the entire start cycle.------
Am I correct in concluding then (as i guessed at earlier) that if one insisted on starting their engine with their shore power and battery charger on that the chance of glow plug damage would be less if the solenoid upgrade had not been done?
lots of hypotheticals,
Ken
The short answer is - of course. The wattage inceases as a square of voltage so increases in voltage rapidly increase wear and aging.
Ron
To clarify my message, when I said the shore power was on, I also meant that my Battery Charger was on, as I always have it on.!!! 8)
Quote from: karista on May 17, 2009, 04:39:03 PM
... I also meant that my Battery Charger was on, as I always have it on.!!! 8)
If that was the case (i.e., charger on all the time and batteries are fully charged) then the charger output voltage should be about 13.4 V in float mode. If it's higher than that, either you just turned it on and it's going through it's cycle, OR your charger should be considered with suspicion for quality battery treatment. With Steve's excellent explanation, you can do the math.
Ken, longer wires mean more voltage drop. Period.
"and battery charger on that the chance of glow plug damage would be less if the solenoid upgrade had not been done?"That's pretty much it. Could be higher voltage but for a LOT less run time. I have the solenoid in and have shortened glow plug time significantly and originally from 20 - 30 seconds before to 12 - 15 seconds with, and have improved that by minimizing it sometime down to 5 seconds, and the engine starts right up. Don't even use them if the engine's been run, and sometime 2 to 3 hours later is still warm enough to start right up without the glow plugs.
Give it a try, and just be careful.
Very interesting topic. Thanks to all.
Everyone - I have a PbCa automotive-type sealed battery as my "start battery". Their acceptance voltage in Bulk mode is over 15 volts. When I engage the glow plugs, they draw 20 amps and my Xantrex XC30 thinks it can go into Bulk mode from Float mode and rises to +15V. Now, I can't actually see the Xantrex display or Link display, but that's my theory on why I fried my new-ish glow plugs while starting the engine at the dock. (This was after having the glow plugs out to do a compression test and the engine wasn't starting because I managed to contaminate the fuel injectors because I had to remove the lines from the injection pump to the injectors to put the compression tester in glow plug hole for cylinder #1, but just before my foot slipped on the Ulimate Sole in the aft cabin and I rolled my full weight on my other ankle breaking it. All in December, no one around the marina, 700 feet down the dock from my car).
Some things you realize should be left for professionals.....but where's the fun in that?
Craig
Footnote, the ankle injury was December 07.
Craig--law of unintended consequences---sorry to hear about your ankle.
Ken
Guys and Ken : All the addition of the solenoid did was to take the "available" voltage/amperage and not let it deteriorate drastically before it reaches the glow plugs where it is needed.
The only way you can get more than battery voltage (about 12.75 + Volts) is to get it from another source like a battery charger!! A thought.
Ron (and guys)
I am convinced that the solenoid upgrade is a good thing. Nevertheless, two things seem clear from this thread. If Westerbeke (Kabota) installed 10.5 volt plugs for a "reason", maybe it was to help guys like me who had let their batteries run down (the pre solar panel days) and were starting the engine on a particularly chilly autumn day. I would have a better chance of starting with these plugs. Secondly a 12.5 volt plug will have more tolerance for excessive voltage (current) at start-up--whatever the reason. It's clear that his is not a good idea so your point, Ron is well taken It seems the solenoid only puts one at risk of plug burnout if the redundancy of a battery charger(or other charging source) is in use when starting. It may also be the case that the 10.5 volt plugs would have less tolerance for keeping the glow plug button depressed for more than the suggested time.. We are dealing with a double edged sword.
Ken
Ken : Let me try again. The batteries at 100% charge are at 12.75volts!!
The whole idea of the solenoid was to reroute the voltage/amperage from the devious wiring that the factory installed - from the battery/s back 15feet to the key switch and then back another 15feet to the glow plugs. This was all done with a #12 gage wire. That's why it took the glow plugs atleast 30 seconds to warm up which also put a real voltage/amperage drain on the battery/s!!
The solenoid shortened that 30ft routing to about 5 feet with a #10 gage wire shortening the switch engagement time to 10/15 seconds. This also was a much lower drain on the battery/s so more voltage is avialable to the starter.
When you engage the glow plug switch there is about a 2 to 3 volt drop on your Vmeter, so the glow plugs are only really getting about 10.5 volts or less.
Enter the shore power charger and it sees a drop in battery/s voltage and it kicks up the voltage to cover the Voltage drop. Now you are getting more volts than the glow plugs are rated for. Even with out the solenoid the higher voltage will still reach the glow plugs if they stay engaged for 30 seconds.
I had the engine manual out for an unrelated issue and noticed the details about the glow plugs.
Resistance - 1.0-1.5 ohms
Current draw - 8-9 amps
Normal energised time - 10 seconds at or above 41F, 20 seconds below 23F
Maximum energised time - 30 seconds
OFF time between start attempts 30 seconds
I believe if the starting limitations above are followed the glow plugs should last a long time. In my case, it is never below 41F when I am starting therefore 10 seconds should be all that is needed.
Most of our manuals talk about a glow plug engagement of about 30 seconds - with NO shore power battery charger on.
I agree with Steve, that if you follow the correct instructions your glow plugs will last. Mine only lasted for 5200 hours and 21 seasons!! AND ARE STTILL WORKING !!