Beta 30 failing to idle

[Oily Rag]

The engine runs well under load. No smoky exhaust. Well cooled. But when reducing to tickover speed in neutral has started to cut out and stall. Primary fuel filter looks fine.

I have a few thoughts, but would be interested in any others. Many thanks.

 

[RivalRedwing]

How many engine hours on it? Any work done on it or its environs recently?

Feels like a small air leak, are the filters tight and the fuel connections snug (but not over tight)?

plenty of other possible options

 

[Boater Sam]

What happens if you simply adjust the tick over speed in the injection pump?

 

[Oily Rag]

Many thanks. Engine is 8-9 years old, 800 hours. No air leak when top of Racor prefilter removed - still full of fuel.

I'll change air filter, fuel pre filter and engine fuel filter on next visit. Then put some load and higher than normal revs.

Only after that will I adjust idle speed. And report back.

 

[RivalRedwing]

I would take a bit of coloured tissue and hold it against all fuel unions in turn to see if any show minor signs of leakage

 

[Oily Rag]

I said I'd report back.

I changed the old air filter, Racor pre-filter and engine fuel filter. Old air filter was grubby in places, but not too bad. Racor looked Ok, but no way of telling with engine filter (secondary).

I bled the system and started the engine. Took it up to 3400 rpm no load. (Boat on a mooring buoy and not sure about putting load on it. Any opinions on that by the way?)

After about ten minutes, reduced to idle speed and it sat at 1000rpm quite happily. Problem apparently solved.

I repeated the start and high speed run a few times, and it idled fine on each. So a bit unsatisfactory, but successful. It works, but I don't know what was wrong. No sign of an air leak and 1000rpm idle seems about right.

A bit like in the olden day, when you changed the rotor arm, distributor cap, ignition leads and plugs and then the car started again!