Westerbeke 7.2 BCGTC Blowing 8A Fuse

B

brianwill

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Dec 31, 2002
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10936
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Westerbeke 7.2 BCGTC (1999) was running fine. Under load, it shut down and would not start (no crank on the starter). Found the 8 amp (automotive) fuse blown and replaced it. Started and ran fine after that. Under load, it shut down again – 8 amp fuse blown again.

Now every time I press the oil pressure bypass switch prior to hitting the start switch, this 8 amp fuse blows. Any ideas?

Thanks,

Brian
 
Thanks Billy. I'm thinking the 7.2 kW might be a little light for my boat...
 
Brian why do you think that 7.2kw is light for your vessel?
Bill
 
My boat is configured with twin 16,000 BTU AC units, three burner stove, microwave, 20 gallon water heater, refrigerator, ice maker and the DC house system. The following year, Maxum put a 12.5 kW diesel generator on this boat which is probably about the right size for this load.

I've had to manually load shed the system when we need to use the galley to keep the generator from an overload shutdown.
 
Hello Brain if your Maxum has a diesel Westerbeke it can't be a 7.2 bcgtc that is a gas generator.
 
Opps Brian. If it is a diesel it should be a 8.0 BTD or a 12.5 BTD You can find the correct model on a foil tag on the electrical end of the generator.The tag maybe missing if it is missing there is also a metal tag stamped into the side of the exhaust manifold.This is the first place to start to find your problem.Let us know.
 
Sorry, I changed gears here. My boat is a '99 gas powered with a 7.2 kW generator. The '99 diesel boats had an 8kW diesel generator. I'm guessing that Maxum realized both of these were not adequate power and in 2000 increased the diesel generator to 12.5 kW. That was the same year they went with only one engine option - the Cummins 450C diesel. The other engine options, Cummins 330B and Mercruiser 8.2L gas (my motors) were discontinued.
 
Wow I have never even heard of a 4600 gas boat much less seen one.This is what I think you will find. Pull off the belt cover on the front of the unit you will see a switch on the front of the block with two wires going to it.Unplug both wires and start the unit see if the fuse doesn't blow. If it runs ok you will need a oil temp switch it's shorted to ground.The unit will be very hard to start and it may stall at first this switch holds the choke on till the oil temp reaches 140 degrees.I see this very often I keep two of these in the service truck all the time.Good luck and let us know.Oh and for the record that is way to small a generator for that boat.
 
Brian, my boat's AC electrical needs are very similar to yours. The only difference is I only have an 11 gallon hotwater heater. I only have a 7.3kw genset. If you properly load manage the boat you could be able to get by with your current unit. George is correct with his comments.
Good luck let us know what you find regarding the cause of the 8A amp fuse blowing.
Bill
 
George, Home port VA, and knows Westerbekes. Engines1 perhaps?
 
No not Engines 1. D.C. Metro area Clean Marine Electronics Inc..Will be at boat show at Expo Center in Chantilly this weekend If you are local stop by and say hi.Keep us updated Brian.
 
Thanks for the info guys - I'll keep you posted on what I find. It's not uncommon to find pretty large boats here in the Dallas-Ft. Worth area with gas engines. Every mechanic out here knows a GM V8 engine. My neighbor had the same boat as me with the Cummins 450C motors and the maintenance was tough. He'd have to call a mechanic to fly in from Houston for any repair work. Makes it much more expensive. If / when we move it to the coast, I'll probably repower it with Cummins QSC 500 engines, but for now under a covered slip in fresh water isn't too bad. I just don't push these motors too hard.
 
This 8 amp. fuse feeds 6 engine devices such as fuel pump, fuel solinoid, ignition coil, hourmeter, choke, and 2 relays. Some device is drawing high current. If so, it should be getting hot. Feel devices for heat. If not hot, install an ampmeter at the fuse...should be 4-5 amps. but probably is 10, and isolate or disconnect devises looking for the current user. Is the choke depowering? Tighten your grounds. Do you have a remote panel...disconnect it. Probably the fuel pump. Or just put in a bigger fuse.
 
quote:
Originally posted by garyham

This 8 amp. fuse feeds 6 engine devices such as fuel pump, fuel solinoid, ignition coil, hourmeter, choke, and 2 relays. Some device is drawing high current. If so, it should be getting hot. Feel devices for heat. If not hot, install an ampmeter at the fuse...should be 4-5 amps. but probably is 10, and isolate or disconnect devises looking for the current user. Is the choke depowering? Tighten your grounds. Do you have a remote panel...disconnect it. Probably the fuel pump. Or just put in a bigger fuse.

Click to expand...


Sounds like pretty good advice except the "bigger fuse" part if 8 amp is what is spec'd to protect the wiring & normal loads in that circuit.
 
Business travel for past two weeks - am hoping to get to the boat this weeked.
 
OK, here is what I have. The 8A fuse blows when the ON switch is activated at the remote panel. If I pull the T7 connector from the circuit board, the fuse doesn't blow (but the generator can't be started either). Any ideas about the T7 circuit and what might be on it that's shorted?

Thanks for the continued help.

Brian
 
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