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Old 01-16-2021, 03:01 PM   #81
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You mentioned the coil ground, what exactly are you referring to. Is it the ground wire going through the relay
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Old 01-16-2021, 03:04 PM   #82
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Originally Posted by twistedtree View Post
I think we need to go back to the symptoms. The schematics help, but I am seeing two versions that are different, so I'm not sure which matches the genset in questions. Regardless, the symptoms are


1) When you engage the preheat switch, there is no clicking of relays or fuel solenoids.


2) When you further engage the start button, the engine cranks but does not start.


With this, and using either schematic, it tells us:


1) The control breaker is on and supplying power. If it weren't, the engine wouldn't crank.


2) The problem is NOT one of the safety switches, or at least they are not the immediate problem. They are bypassed when you hit the preheat switch, and the relay/solenoid should click regardless of the safety switch status.


3) The problem isn't the preheat switch itself. The same problem exists at both panels with different switches, and the pre-heat switch supplies power to the start switch, and the start switch does what it's supposed to do. So it's getting power.


So what's left is the relay or a wiring failure between the preheat switch and the relay. The OP tested the relay, but I'm not 100% clear on what was checked. But I think he confirmed that the preheat signal was reaching the relay, but the relay wasn't energizing. Now that still leaves some wiring failure possibilities like the relay coil ground, but is most likely the relay. There is a second relay shown in one of the pictures, so a simple and conclusive test would be the swap the relays and see if the problem follows the relay. I don't think he tried that, but instead elected to just get a new relay.
Yep, and this is all looking more and more like my 4 year issue mentioned here.
And a workaround that I use to make genset run.

https://www.trawlerforum.com/forums/...5&postcount=29

I to have swapped out relays with no joy so its gotta be a wire "somewhere" in ours
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Old 01-16-2021, 03:10 PM   #83
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What is the exact model of your generator? I want to see if I can find a schematic.
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Old 01-16-2021, 05:02 PM   #84
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7.6 btd
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Old 01-16-2021, 05:03 PM   #85
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I have swapped all the relays but still The preheat switch will not activate anything. I can bypass and jump each one of the switches and they work fine.
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Old 01-16-2021, 05:05 PM   #86
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It appears that I’m getting voltage to the relays but nothing after that.
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Old 01-16-2021, 05:06 PM   #87
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The history to it, is that the generator overheated and shut itself down. The last time this happened I had to put a new water temperature switch in. But it appears that that is not the same problem now
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Old 01-16-2021, 05:56 PM   #88
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Dkk,

I sent you a PM. Give me a call, if you'd like.

Cheers!
-Greg
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Old 01-16-2021, 06:25 PM   #89
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Greg, I just replied to the p.m. I’m over on Island estates
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Old 01-16-2021, 07:29 PM   #90
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No I saw that switch and it was actually on
If you have access to that switch pull the terminals off gently and check resistance over that switch with it in the closed and open position. If you cant access it cycle the switch many times back and forth to see if you can possibly knock off some corrosion and try again. That switch will cause that issue. You have checked many other items and they seem good. But other than confirming that switch is in the correct position you haven't assessed it for serviceability.

For some reason on mine (4.4) it will occasionally move to the other position from vibration. I crank it and start troubleshooting and then remember that damn switch. I usually just put it in the opposite of whatever position its in and try it again and it starts right up. I think i am going to move it to a better location and label it better.

But you might want to rule that switch out. Ideally you want to not even breathe on it...and gently pull the wires off and put you meter in ohms and read the ohms through the switch. One probe on each switch terminal. You want to see .1 or .2. If you get a reading like 4k or some very high reading then that is likely the issue.

***edit*** Im off Monday and going to my boat in Tarpon Springs to do some work. I may be able to stop by if you still dont have it fixed. Your about 25 min south of Tarpon it looks like.
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Old 01-16-2021, 09:09 PM   #91
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from schematics;
i would check the 10A fuse/breaker at pre-heater solenoid. if it is good, that i would bypass the solenoid it self and try to start the generator. replace the solenoid if it starts.
if not then I would bypass the main switches that will prevent the generator from starting if they are bad one at time (exhaust temp switch, water temp switch, oil pressure switch).
Happy troubleshooting,
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Old 01-16-2021, 10:42 PM   #92
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So, here's my take on a potential ticklish bit on the human factors side of things...

It seems like failure to /maintain/ the preheat button in a depressed state until /after/ the engine is started and, further, until /after/ oil pressure gets up to 10lbs, would be a common error for those unfamiliar with this family of generators -- and one that would prevent the generator from running. See page 9 of the operator's manual below:
-- https://www.westerbeke.com/operator'...erator_man.pdf


The schematics for the generator can be found on pages 41 and 42 in the service manual:
--https://www.westerbeke.com/technical%20manual/38673_5bcd_bcda_bcdb_technical_manual.pdf

Given the schematic, here's my take on the debug workflow...

Under normal operating conditions power to the fuel solenoid, which pushes the fuel rack into the run position, and power to the fuel lifter pump, are supplied via the circuit with the safety switches.

But, this can't happen until the unit unit is running with sufficient oil pressure to close the normally open oil pressure switch. In order to enable the unit to start, the "Preheat" button operates the preheat solenoid, which, via a circuit breaker, supplies the fuel pump. And the same starter solenoid which operates the starter motor supplies power to the fuel solenoid to push the rack into run position.

Since the engine is cranking, the start solenoid is doing its job. So, the side plate should be removed from the fuel pump to visualize the solenoid and fuel rack. If the rack is pushed into the run position, the problem is not there. If it is pushed, but not fully into the run position, the fuel solenoid may need inward adjustment, may not be getting enough voltage, or may be weak. That should be debugged by checking the voltage into the hold coil and back-tracking as needed, or adjusting the solenoid, as needed. If the solenoid is getting proper voltage, but is not operating the rack or in need of adjustment, the rack can be manually operated for testing. If the rack moves appropriately and the engine starts, the solenoid should be replaced.

If the solenoid moves the rack into position and then it falls back, that points to a failure in the "hold" coil circuit. It should be checked for 12V at the input to the oil pressure switch and debugged backward through the other normally-closed sensors to the source, as needed. If the oil pressure switch is getting 12V it should be /briefly/ bypassed. If this corrects the problem, oil pressure should be verified with a mechanical gauge and the oil switch replaced as needed. If the hold coil doesn't hold when given 12V, the fuel solenoid should be replaced.

While the preheat button is being pressed, fuel pump should be felt and listened to for activation. The output line can also be loosened to check for flow. If the pump is turning on but not supplying fuel, fuel supply to it should be (re-re-re-)checked starting with the valves and then filters. The supply line can also be opened and checked for flow with gravity or another pump. If there isn't a problem supplying fuel to the pump, and the pump isn't supplying a solid stream of fuel, it should be replaced.

If, when the preheat button is pressed, the fuel pump doesn't get voltage, the ground should be checked, and then the positive should be traced backward and checked at the circuit breaker, and then the preheat solenoid, and then the input to the solenoid, and then the coil to the solenoid and then the preheat button.

Cheers!
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Old 01-19-2021, 07:37 AM   #93
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Pretty much sums it up.
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Old 01-23-2021, 09:58 PM   #94
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Dkk3000 and I are nearly neighbors, so we debugged this together. Just posting to close the loop for posterity in case anyone searches this issue in the future.

The genset controller was a different spec than the schematics that I'd posted here. I think he may post a photo of the schematic and ladder diagram here, also for posterity.

In this unit's controller, there is a diode that feeds power around the safety sensors while the pre-heat button is pressed without allowing it to back-feed once the oil pressure comes up and the oil pressure switch closes, providing the primary current path to the fuel pump and solenoid. This diode failed open. Upon replacement, the problem went away.

It is also worth noting that the way this unit was wired, likely in part to keep the wiring simple while ensuring that the remote stop switch works, the remote panel needs to either be attached or bypassed, or not everything that should get power does.

As an aside, we also found the preheat solenoid to be bad. But, this affects only the glow plugs, themselves, and the generator starts up fine without them, at least in the Sunshine State.
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Old 01-25-2021, 08:11 AM   #95
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Glad you got up and running! Were you able to just replace the diode, or did you have to spring for an entire new board?
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Old 01-25-2021, 08:18 AM   #96
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Glad you got up and running! Were you able to just replace the diode, or did you have to spring for an entire new board?
Just the diode. But, there was no trick. Not even any solder work required. It is an old school controller. The diode is right across two screw terminals in a terminal block.
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Old 01-25-2021, 08:46 AM   #97
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Good troubleshooting fellas. Diodes throw off quite a few people. But of course it helps to have the proper diagram as well. Great job and I'm sure your wallet thanks you as well.
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Old 01-25-2021, 10:16 AM   #98
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