Engine circuit breaker tripping

[unbusted67]

Well the only thing that could be tripping both breakers, the new and the old, would be current going to ground. I would look into the solenoid and maybe the starter?

[Mickeyrouse]

May be a crazy set-up, and how no one else would set up a boat. But that's the factory set-up from Westerbeke for this and just about every other red engine they've shipped for the past 30 yrs- they haven't changed their standard wiring diagram in at least that long, or since they started marinizing Mitsubishi and Isuzu short-block small diesel engines- most of these have a fuel shut-off solenoid requring it to be energized as long as the engine is expected to run.

[Mickeyrouse]

See initial post re starter

[FamilyVan]

Hey, I'd love to have a nice newly installed Westerbeke and associated electrical. I'm just accustomed to an older style of motor. Mines a pain to start 1 (maybe 2) days out of 5. We all have our frustrations. I just didn't realize electrical problems on a running diesel were even a thing.

I considered a repower 2 years ago because of my hard starting Perkins and my mechanic (and kubota dealer) talked me out of it. I'm following this thread to learn, not judge.

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[Sardean]

Hi mickyrouse
The way your Circuit breaker is tripping suggests an overload oI think its a 20amp breaker.
The breaker works by heating up a bimetallic strip during an overload then it triggers the tripping mechanism. So a loose terminal on breaker can cause heat and early tripping. Probably not the problem as you replaced breaker.
If a solenoid dosnt pull all the way in it will draw excess current, if this is the problem solenoid will be very hot and normally make a vibrating noise. My way of faultfinding your situation would be to put my DC clamp meter on wires untill I measured what was drawing too much current.
If you have an amp meter on your boat you may be able to use that to read your amps draw.


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[rbauman]

Which circuit breaker is tripping, the 10A or the 20A one?


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[Mickeyrouse]

The re-setable 20 Amp breaker is trip-happy, and replaced.
Good idea re clamp meter on solenoid- if I can just get it to run long enough to jump down and measure it.

[Sardean]

Solenoid should draw less than 2 amps unless it is faulty

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[Mickeyrouse]

I haven't noticed any audible rattling from the solenoid. The finger seems to be pointing there, except that with the shutoff solenoid in the circuit and the starter solenoid out, the breaker didn't trip.(sigh!)

[Sardean]

Looking at wiring diagram my best guess is that the preheat solenoid may be jammed on

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[Mickeyrouse]

Think what I'll try is this: jump across the breaker terminals to in effect take it out of the circuit, turn the key switch to the "on" position (not cranking the engine) then check the suspect wiring at the solenoid for current draw and feeling the solenoid for warmth. In looking at the diagram, I realize that when eliminating the starter motor solenoid by taking it out of the circuit, that also takes the fuel solenoid out, so if that is the problem, its condition is obscured because I disconnected the starter solenoid at the terminal of the pre-heat solenoid. (Too many solenoids on the same circuit, no?)
I Can take the fuel solenoid out of the circuit from a terminal on the starter to eliminate that.

[rbauman]

The wiring diagram indicates a current timer/fuel solenoid on the 12C, 20B, 30B, 35C and 44A only (when used). You definitely have a fuel solenoid? If you do, I would try disconnecting that from its existing supply and powering it from another 12v source, putting an ammeter in series if possible. My multimeter has a 20A current capability, for example. Either way, the engine should then start and run without tripping the breaker if the fuel solenoid is the culprit. I tend to suspect the lift pump is causing the excessive current draw. The fact that the engine will run when cold but will trip the breaker on a restart could mean the oil pressure switch may still be energized due to residual oil pressure during the restart allowing the current to the lift pump. Again, you could isolate the lift pump and using another 12v source, measure its current draw. The other possible culprit is the field supply (P lead) to the alternator. The alternator has an internal regulator so I would disconnect all leads to it to test that theory.

[roberthowell]

you could always bypass the circuit breaker and keep the fire extinguisher handy

[deblen]

Jumper the ckt breaker with an inline fuseholder with fuse of same amps or one step larger than the breaker.That will prove a good breaker if fuse blows or bad breaker if fuse does not blow.

Cheers/Len

[Sardean]

Be careful bypassing circuit breaker as the time delay simulates wires getting hot during minor overloads and trips before wire insulation melts. if I bypass a breaker it is only for short period of time for fault finding or for an emergency situation.

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