Westerbeke 4.5Kw genset surging at idle

CJ Martin

Member
Oct 4, 2006
762
Great Mills, MD
Boat Info
2002 320DA
Engines
350MAG Horizons / V-drives
Fired up the genset today and it was surging quite a bit at idle (no load). By surging I mean the rpm would slow to near stalling, then back to normal idle. Waterflow was good, and under a load it smooths out and runs fine. This is the opposite of what I would expect from fouled plugs (plus were new this spring).

Thoughts?

-CJ
 
Choke sticking maybe?

I agree it doesn't sound like plugs, but I'd probaby throw the 5 bucks at it anyway.
 
CJ Martin said:
Fired up the genset today and it was surging quite a bit at idle (no load). By surging I mean the rpm would slow to near stalling, then back to normal idle. Waterflow was good, and under a load it smooths out and runs fine. This is the opposite of what I would expect from fouled plugs (plus were new this spring).

Thoughts?

-CJ

I had the fuel bowl gasket leaking this year, which flooded the engine while running and stalling it after surging and smoking. Happens when you don't use them enough. Could be the governor?? How many hours on the genny? Ever checked/changed oil in the governor??
 
The genset was serviced this spring (oil changed last fall) and we run it quite a bit. It has 358 hours on it.

I'll look into the governor but wouldn't that cause a problem all the time? My problem is only at no load idle. Loaded up it smooths right out and runs great.

I suspect a fuel problem, so my plan now is to start at the fuel filter and work my way to the carb. All that bouncing last week to/from the BiH must have shook something loose.

-CJ
 
CJ Martin said:
The genset was serviced this spring (oil changed last fall) and we run it quite a bit. It has 358 hours on it.

I'll look into the governor but wouldn't that cause a problem all the time? My problem is only at no load idle. Loaded up it smooths right out and runs great.

I suspect a fuel problem, so my plan now is to start at the fuel filter and work my way to the carb. All that bouncing last week to/from the BiH must have shook something loose.

-CJ

Is it "surging" or "hunting". If it is hunting then the gain needs to be adjusted. This is a minor adjustment that is described in your Operators manual.

Typically in a no load situation the controller can be sensitive to the gain setting which moves the throttle up and down. The purpose of adjusting the gain is to make the unit more responsive to loads. The higher the gain, the quicker it responds but the side effect is hunting with no load. If the gain is low, the system may not respond quick enough to a load (such as an AC system switching on) and the unit will bog or shut down.

-John
 
John,

Thanks - "hunting" might be a better term. I've found the adjustment info in the manual and hope to try that this Friday afternoon. Seems pretty straigtforward.

-CJ
 
CJ Martin said:
John,

Thanks - "hunting" might be a better term. I've found the adjustment info in the manual and hope to try that this Friday afternoon. Seems pretty straigtforward.

-CJ

It is ...just be careful. There are some large capacitors/ac voltage under the cover that will send you to the hospital (or worse).

With the unit switched off, remove the metal cover and locate the controller. Most look like 4"x5" black plastic with two very small controls on them.

One set screw is for engine rpm which you do not need to touch and the other looks like a little clock with an arrow in the center. That is the gain adjustment you are looking for.

Follow the instructions in the operator manual and you will be good to go.

-John
 

Forum statistics

Threads
112,946
Messages
1,422,769
Members
60,929
Latest member
Henchman
Back
Top