Westerbeke generator owners

[PlayDate]

Although Westerbeke has not released a Service Bulletin on the subject, a number of Westerbeke owners are experiencing a problem that it almost impossible to diagnose. The problem turns out to be the oil pressure switch part number (Westerbeke): 37323.

Symptoms:

Generator starts, runs and randomly shuts down with or without a load after the engine has warmed up. What appears to be a fuel problem is actually the oil pressure switch opening which triggers the control board to shut the engine down. For clarity, there are two oil pressure switches on most Westerbeke generators. Switch "A" (37323) is normally OPEN and closes when the engine starts and oil pressure keeps it closed. Switch "B" is normally CLOSED and opens when the engine starts and oil pressure keeps it open. Switch A manages the control board. Switch B usually connects to Sea Rays monitoring system.

Switch A is the issue. After the engine warms up, the threshold of the switch seems to open (and shut down the engine) even though there is more than sufficient operating oil pressure. What makes it particularily vexing to diagnose is that the switch appears fine when it is tested. In fact the generator will often restart and run fine then 10 minutes later will shut down and not restart.

If you find you are having these symptoms, switch A could be the issue. It is possible to bypass switch A to test the system by closing (jumping) the two leads going to the switch. However, that should be a short test since a real oil pressure problem could exist. I normally remove the switch and use a mechanical oil pressure gauge to test the oil pressure when I jump the leads.

This switch is used on both gas and diesel generators.

-John

 

[Boat Guy]

How far back does this issue go? Both gas and diesel?

 

[johnsross3]

John, thanks for a very useful post!

 

[Xplicitlnck]

Do u have info on years or models?

 

[trit21]

So are you saying that all switches 37323 are bad. Bad design? OR ?

 

[PlayDate]

The issue seems more prevalent in gas and diesel generators that are over 5 years old. That switch, to my knowledge, has been used on most if not all Westerbeke generator models over the past 10 years. While it is pure speculation, Westerbeke buys these switches probably a 1000 at a time and the likely hood of a failure over time is hard to predict. The fact that it misbehaves when the engine is warmed up.....leads me to think that heat is related to an early failure of the switch. The problem is when you buy switches in bulk (think about General Motors recent woes)....some if not all of them can have similiar issues.

It is a $20 item.

John

 

[Xplicitlnck]

So keep one onboard

 

[Pettibone1]

Thank you for the useful info.


Sent from my iPhone using Tapatalk

 

[dwna1a]

Thank you very much for the post! I try very hard to watch for SB's on our GenSets if I see it I will post it

 

[Nauti 97]

John
I am having shutdown issues with my 1997 Westerbeke 7.0 BCG generator.
Could it be this switch?
Where is the switch located on the Genny?
I am going to clean the heat exchanger but would like to have the new switch ready if cleaning doesnt solve the issue.

 

[Xplicitlnck]

I'm having that issue now. I jumped the oil pressure switch that's is attached to the block but nothing. Problem still exists. I cannot find the second oil pressure switch. Any ideas on were it might b. I have a 98 bcga.

 

[PlayDate]

You would think by now that Westerbeke would have come up with a led fault indicator by now. It just doesn't make sense that they make it such a painful process to diagnose fuel and safety problems.

So to answer your question, there are two basic shutdowns:

1) After running for more than 15 minutes. -At this point the generator is warmed up and usually experiences a safety shutdown due to: high exhaust temp, low oil pressure, engine temperature, engine overspeed or an unusual load that the unit cannot recover from. Additionally, marginal fuel pressure or gain adjustment can create the same symptom. If it is a safety shutdown, the unit will restart and die once the momentary (pre-heat) switch is released. At that point, you have to isolate and test the sensors one by one.
Quick diagonostics:

-You can eliminate the high exhaust temp and engine temperature with an IR thermometer (which every boat owner should have). Clogged exchanger or raw water pump issues are likely if the temps are high.

-Over speed is unlikely unless someone has messed with the generator

-Load and gain problems are probable if the unit restarts and runs forever without a load.

-The oil pressure sensors (two -one normally closed and the other normally open) are not that easy to bypass. If suspect, they are cheap to replace. The problem sensor is the "run" sensor which attaches in the same area as the "start" sensor. It is usually behind the start sensor closer to the engine block.

2) Running for less than 15 minutes- Generally, this is a fuel problem....especially likely if it can't hold a load. Bad or stale fuel is the number one gas generator issue after de-winterizing. Stale fuel looks like a wide range of mechanical problems and just takes patience to clear. The smaller engines just are more sensitive to stale fuel. If you are certain the fuel is fine then the fuel pump, filter and water separator need to be inspected.