Volvo Penda AD31B engine trouble.

[Purple Velvet]

I had one of those days today! Fairline Targa 27.

I was investigating a raw water problem with the starboard engine, which required me to crawl all over both. A little later I ran up the port engine which was faultless, but a minute later it started to falter and then cut out; all the symptoms of fuel starvation. Tank is over half full of good diesel and the starboard engine started fine from the same tank.

It there perhaps an "emergency fuel cock" on the engine itself that I might have disturbed please?

 

[James jameson]

I’d be looking at what you might have disturbed. Loose fuel pipe, filter anything to let in air in to the fuel system. Or a simple as knocking the isolator off Can’t be much

 

[Purple Velvet]

I’d be looking at what you might have disturbed. Loose fuel pipe, filter anything to let in air in to the fuel system. Or a simple as knocking the isolator off Can’t be much

1) The usual culprit:


fuel shut-off lever on the injection pump








On the Volvo Penta AD31B marine diesel engine:

• There is a manual stop lever on the injection pump
• Often linked to:
  • A cable from the helm
  • Or an electric stop solenoid

What happens

• If it’s nudged:
  • It partially closes fuel delivery
  • Engine runs briefly → then dies (exactly your symptom)

Very easy to catch with an arm or clothing when leaning over














2) Also very common:


primary fuel filter / water separator








You’ve been crawling around near:

• Bulkhead-mounted filter (CAV / Delphi type usually)

Possible disturbances:

• Slight air leak at top seal
• Bowl disturbed
• Drain screw loosened

Symptom pattern:

• Starts fine
• Runs for 30–60 seconds
• Dies as air reaches injection pump

3) Lift pump / priming lever








On the engine:

• Mechanical lift pump with a little priming lever

If disturbed:

• Can sit in an odd position
• Or a marginal diaphragm shows up

4) Fuel line disturbance








Very likely given your activity:

• Slightly loosened union
• Hose flexed → draws air
• Clip shifted

Diesel systems will:





Run briefly, then die once air reaches the injectors

 

[James jameson]

Chat GPT answer ?

 

[Purple Velvet]

Chat GPT answer ?

Indeed. It remains to be seen of it is useful, but it is worth a look.