Installing an indicator light in parallel with your glow plugs might be an easy way to know for sure when your glow plugs do & do not get power.
Westerbeke Preheat Power by Key 'On' Position
- Thread starter GRM
- Start date
When the PO rewired the Admiral panel on my boat, the keyswitch can rotate counterclockwise and turn on the glow plugs. You have to hold the key in that position because it autoreturns to the OFF position. Clockwise is ON and START with the START position being momentary also.
Mine is exactly as described by JViss above....I use the pre-heat button for a few seconds prior to starting the engine. I have both pre-heat and start button...Pat
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,948
GR
You can never know or guess at what a Previous Owner did to the boat. We all start with the hope they asked for professional help or at the least sought out a group with some experience before changing the wiring. At this point you have to be the eyes and the decision maker.
One if the weather and the fuel are warm enough, and your engine has good compression you can start and run a diesel engine with out the use of the glow plugs. It sounds like you have proven this based on your response. This will not continue.
One of the easiest keys to understanding if the glow plugs are functioning when you start your engine has been identified for you. Look at the voltage meter as you start the engine. If you turn the key to on and the voltage meter stays above 12 volts then you have a massive battery bank or the glow plugs (which are a heavy draw against your battery) are not heating.
If you go beyond the spring load point and the battery voltage meter indicates a big power draw then you are firing the glow plugs and your engine will soon be ready for the starter (indecently another big draw on the battery).
If still at a loss take a picture of the wires on the switch and post them here. One of the many contributors may have seen the exact same configuration and can give you an instant answer.
Best of luck with your boat and welcome to the forum.
You can never know or guess at what a Previous Owner did to the boat. We all start with the hope they asked for professional help or at the least sought out a group with some experience before changing the wiring. At this point you have to be the eyes and the decision maker.
One if the weather and the fuel are warm enough, and your engine has good compression you can start and run a diesel engine with out the use of the glow plugs. It sounds like you have proven this based on your response. This will not continue.
One of the easiest keys to understanding if the glow plugs are functioning when you start your engine has been identified for you. Look at the voltage meter as you start the engine. If you turn the key to on and the voltage meter stays above 12 volts then you have a massive battery bank or the glow plugs (which are a heavy draw against your battery) are not heating.
If you go beyond the spring load point and the battery voltage meter indicates a big power draw then you are firing the glow plugs and your engine will soon be ready for the starter (indecently another big draw on the battery).
If still at a loss take a picture of the wires on the switch and post them here. One of the many contributors may have seen the exact same configuration and can give you an instant answer.
Best of luck with your boat and welcome to the forum.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,948
Depending on how the volt meter is wired, this may or may not work. If the meter wires go straight to the battery, then you may see little or no voltage drop when the glow plugs come on. If the meter is connected further downstream in the wiring harness, then you may see a massive drop.
Actually, I believe that it is true because of the different resistances of the different wires in different parts of the wiring harness. If you run 20 feet of #10 wire from a battery to a 30 amp load, then measure the voltage at the battery & at the load, you will normally get a higher voltage reading at the battery posts compared to the reading at the load. Please try it if you don't believe me.
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I was choosing not to assume that the wiring in the boat had never been altered by a previous owner or previous repair guy.
If you see a voltage drop when you push a button or turn a key that is supposed to energize the glow plugs, there is a very good chance that the voltage drop is due to the load of the glow plugs, as you expect & as would normally be the case.
The voltage drop means that a load has been added. It does not tell you that the added load is necessarily the glow plugs. Perhaps that added load is a solenoid or some other load that was incorrectly wired. I recommended that you add an indicator light in parallel with the glow plugs, because that is a reliable way of knowing if power is present at that specific node or not.
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It doesn't matter where the meter is, the voltage will drop. How much is inconsequential to the discussion and will differ from boat to boat, and on the same boat depending on way more factors than are needed here. If the meter doesn't move at all, then the glow plugs are not operating. It can be that simple.
Wires of various thickness constitute a resistance network. Both Norton's Nodal Analysis & Keirchoff's Current Loop laws show that it does "matter where the meter is".
Depending on where the meter is wired & the condition of the battery & the sizes of the other wires in the system, you may see a voltage drop as small as 10 or 20mv when the glow plugs come on. This small difference may be too small for some meters to indicate. Therefore I believe that it is not inconsequential.
I agree with you about the variations from one boat to another. I agree with you that it can be that simple. I also believe that in some situations, it might not be that simple. I chose not to assume that this particular situation is necessarily one of the simple ones, but perhaps it is.
I wanted to take a moment to thank everyone who offered suggestions. I have gotten further, and possibly solved the issue. I believe I've uncovered a few facts:
- The key, in fact, does have a position further than 'on'. The preheat is wired to this position, as far as I can tell. It seems to preheat correctly and the engine starts much faster.
- I have been starting the engine without preheat (which has only been a dozen times, all in the past month)
- Tracing all circuits, the oil pressure switch was disconnected (seemingly vibrated loose?) this was causing the alarm to suppress and arm itself at odd times, which I misdiagnosed as a preheat failure (since the preheat circuit disarms the switch).
All of this said, I reconnected the oil pressure switch, gave it a crimp and the engine signals and preheat all seem to work as expected. Thank you everyone for your help, and I hope as I learn I can help others.
- The key, in fact, does have a position further than 'on'. The preheat is wired to this position, as far as I can tell. It seems to preheat correctly and the engine starts much faster.
- I have been starting the engine without preheat (which has only been a dozen times, all in the past month)
- Tracing all circuits, the oil pressure switch was disconnected (seemingly vibrated loose?) this was causing the alarm to suppress and arm itself at odd times, which I misdiagnosed as a preheat failure (since the preheat circuit disarms the switch).
All of this said, I reconnected the oil pressure switch, gave it a crimp and the engine signals and preheat all seem to work as expected. Thank you everyone for your help, and I hope as I learn I can help others.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,948
GRM. way to go. I always get a thrill solving the systems of boats. So often it is the simple things that disable the boat. Always it is the last thing I try that solves the problem... At least till the next thing pops up. The Diesel starting without the use of the glow plugs was deceiving. These little tricks that occur with boats can lead us to blame the boat's inner spirit - almost human being.
Enjoy your new boat. Share your discoveries and experiences.
Enjoy your new boat. Share your discoveries and experiences.