Generator Alarm

Russ Calasant

Active Member
Dec 9, 2009
2,128
East Greenwich, RI
Boat Info
2001 480 DB
Engines
CAT 3196
i have a 12.5 Westerbeke that was blowing the fuse at start up on the control panel at the gen. It proved to be two sensors, water/temp and one of the oil switches. After putting everything back together the alarm on the systems monitor now sounds immediately upon starting (cold). Temp gets to 180 / 185 with a load, good flow and the oil pressure is 49psi- according to the panel. I let her run 15-20 minutes with no change and constant ringing of the alarm. I tried jumping all three sensors individually with no difference. Anyone have any ideas? I cannot figure it out.
 
First, I don't know about this on the 12.5KW genset, but on others the Sea Ray systems monitor is completely independent of the Westerbeke safety switches. Look for a separate temperature sender on the engine....on the 8.0BTD they just used a plug in the cooling jacket and it is on the baqck side of the motor where you need to be standing on your head holding a mirror to locate it.
 
Update, the searay monitor monitors oil pressure. That may or may not be why there is an auxiliary sensor on the gen. I changed the oil and checked it, pressure is 49 psi. Temp is 180. Curiously the mechanic that repaired the gen replaced one of the pressure switches with a NAPA switch - the other with an OEM. If I understand it correctly these switches have different psi levels to switch to ground or open and I assume they have a different resistance if measured ? Maybe it's the issue and the reason the SR monitor is alarming?
 
Russ,
Don't you still have the oil pressure switches you removed? Just put the old SR switch back in there and see if the problem goes away. It shouldn't have anything to do with the fused Westerbeke circuit.

-John
 
Solved - the two oil switches are different, the gen does not care which one is in which hole it will run regardless. However the systems monitor does, with the wrong switch in the top hole the alarm will sound as the system sees no oil pressure even though there is. Swap the switch or the wires - black and white wire is the SR monitor wire on mine.
She ran well for about an hour and shut down again, same symptoms and result. This time I found a relay and the fuse holder itself to be bad. Been running under load for 4 days now without issue.
 

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