Westerbeke 4.5 blowing 8 amp fuse

AllTideUp

Member
May 6, 2013
194
Northern Virginia
Boat Info
2003 SeaRay 380 Sundancer
Engines
8.1s - 370HP
Hello all,

Have an problem with the Westerbeke 4.5 Generator on board my 2001 340DA. A couple of weeks ago we were anchored out for the weekend, had the generator running for ~2 days. While we were on shore the generator shut off and I found that the 8amp fuse on the Gen had blown. There was a "Bussman MTH8" fuse in there but as I read on the Bussman site, this series of fuse is no longer produced and has been replace by the AGC fuse instead. I tried replacing it with the appropriate AGC 8 amp fuse and it blew that as well.

I read that it could be a worn wire somewhere grounding out the system, I have not found any worn wires that appear to be causing that though. I have not taken the control panel cover off yet though, just observations from visible wires.

With some trouble shooting if I put a new fuse in, and turn the "Start/Stop" switch to the run position (one click up), the fuse blows immediately. I replaced the fuse (with all switches off), and then tried to start the generator using the onboard switches and not the remote from the cabin. It started and I ran it for about a min while holding the on switch on the gen since it would have just quit had I let go.

Next test, still good fuse, went to the remote in the cabin, all switches off. Held down the "Preheat" button then turned the generator to the run position. I could hear the normal clicking and sounds it normally makes when in this position for about 1-2 seconds, then the fuse blew.

Any Ideas as to what is causing this?
 
Check the starting battery for the Genset, I had a bad battery and was blowing the house fuse like you. I replaced the battery and haven't had an issue since.
 
I had the same issue. After tracing all the wires as I thought i had a shorted wire. I went back to basics and followed the wiring diagram ( I should have done this 1st). My problem was a bad sensor. It was a water sensor . Changed it and it worked perfect. The sensor when it fails blows the fuse to protect the engine

John
 
top right i circled it
 

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New boat to me also with a 4.5 bcgb. I just checked the zinc and found a good shotglass full of sand and/or mineral chunks. Easy to clean out, but surprising.
 
LUnaCY.....I don't have a Westerbeke Generator, but if there is sand in your heat exchanger, you may want to check your water pump impeller. Sand can chew those things up very quickly.

Jaybeaux
 
Thanks! I did just pull and indpect that and the raw water intake filter too.
 
Well, I tested the battery, it was fine. turns out it was the coolant Temp sensor that was bad.. I just by-passed all sensors then added them back one at a time till the fuse blew. Just so happens that was the first sensor I added back.

So I'll be replacing that and probably the exhaust temp sensor as well for good measure as I think it was giving me problems earlier this year.

Just for note, the original fuse that was in it is no longer made so it is recommended to find the bussman AGC 8amp fuse as a replacement. I couldn't find an 8 amp fuse anywhere locally so I ordered them from amazon. Now I have a good stock of them.
 

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