Westerbeke 3 cyl generator problems

T

Timothy Weiland

New Member
Jun 29, 2021
9
Boat Info
97 searay sundancer 400da
Engines
7.4 mercruiser
I have a westerbeke 3 cylinder generator in a 97 400da. I just have had the boat for 7 years and just got it running last Friday after changing the cap, rotor, fuel separator and fuel pump. I also cleaned the carb but it was pretty much spotless. The generator starts right up and runs well with no load. If I add a small load it still runs well. I can add one AC and it runs but sounds like it is struggling and if I add the second it struggles even more with excess fuel smell coming from exhaust. When I first got it running it wasn't pumping water so I checked the raw water impeller and it looks like brand new. I pulled the hose off the heat exchanger and it immediately started flowing so I put it back on and got water flow. The next day I had to pull the hose off to get it to flow again and still have the same running issues. I suspect the heat exchanger needs cleaned and is causing the problem. Any advice on flushing without removing and does it sound like I'm on the right track
 
You can try back flushing the heat exchanger with a hose. Also clean the strainer and back flush the raw water supply hose before the strainer. Run for ~5min or so with the dock hose on full. That might help the water flow issue. If no joy, then a radiator shop can boil it over night and you should be good.

As for the generator struggling under a big load, you don't specify what the generator is power wise? I am guessing 7KW? if so what you are seeing or hearing is typical, especially for a gas generator. What you need to monitor is the hertz and voltage output. The hertz should be 60hz +/- 2hz. And the voltage should be ~120v AC. That will tell you how the generator is doing producing electricity. Keep in mind you are going to have to regulate what is on and running while using the generator, if you gen set is wired for 120v ~60 amps or 220v ~30 amps, each AC will draw ~15 amps on compressor start, hot water heater 10-15 amps initially. So you wil need to manage what is running.
 
It is a 7kw, two other boats have the same set up and within a couple years at my club. They can run everything all at once even though they usually don't. When it goes to Rev up it runs very rich like it's dumping fuel but not reving up. I'm going to check the timing also this weekend. I might unhook the heat exchanger and just let it pump in the bilge for a few minutes to see if it will Rev up


  1. SKybolt said:
    You can try back flushing the heat exchanger with a hose. Also clean the strainer and back flush the raw water supply hose before the strainer. Run for ~5min or so with the dock hose on full. That might help the water flow issue. If no joy, then a radiator shop can boil it over night and you should be good.
    Click to expand...
SKybolt said:
As for the generator struggling under a big load, you don't specify what the generator is power wise? I am guessing 7KW? if so what you are seeing or hearing is typical, especially for a gas generator. What you need to monitor is the hertz and voltage output. The hertz should be 60hz +/- 2hz. And the voltage should be ~120v AC. That will tell you how the generator is doing producing electricity. Keep in mind you are going to have to regulate what is on and running while using the generator, if you gen set is wired for 120v ~60 amps or 220v ~30 amps, each AC will draw ~15 amps on compressor start, hot water heater 10-15 amps initially. So you wil need to manage what is running.
Click to expand...
 
Sounds to me like your governor, potentially. Check to make sure the linkage is free/clear and moves as it should. You may also want to make sure it's topped off with oil.

I have the same boat, same generator. That generator will run the entire boat, both AC's running cold, water heater humming along, all of it...so long as your wife isn't drying her hair :)
 
I will definitely check the governor oil this weekend. I can easily move the linkage but even the doesn't make it Rev up. It just dumps more fuel and starts sucking more air like it is struggling to Rev up
 
Stee6043 said:
... I have the same boat, same generator. That generator will run the entire boat, both AC's running cold, water heater humming along, all of it...so long as your wife isn't drying her hair :)
Click to expand...

Friend has the same boat, same generator and turning everything on blew the back end out twice.
That was why I mentioned it. Maybe his wife running the hair dryer :)
 
What Stee60 advised, check your gov oil and linkage. I’d bet it’s the oil.

It only takes 3oz but makes one hell of a difference and can drive you crazy if you don’t check it. Also check the engine oil
 
I read that you have 2 separate issues.
Sounds like you are losing prime on the raw water circuit. The smallest of air leaks will cause a loss of water in the line. I'd check all the hose fittings and the back plate of the raw water pump. make sure the paper gasket doesn't have a tear in it.
Get yourself a power monitor, plug it into the cockpit outlet on an extension cord, and you will be able to adjust the engine speed to get the correct hertz. That is more important than the voltage, although it should follow. I don't see where you have changed the spark plugs. That is an annual thing on the 7.0BCG Chances are one is fouled, and under load, it fouls even more.
I use this when I am adjusting the speed control
AC_SL1000_.jpg
And, I have one of these permanently mounted on the dash
ac panel meter 2.jpg
Disregard the euro numbers. It does 80 - 240v and a wide range of hertz
 
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