Engine problem

[rakaaw]

Engine in question is a Mitsubishi K2C 600L. marketed by Sole’ Engines as a Mini 14. It is a basic 2 cylinder diesel.
The engine has been trouble free during the twelve years of my ownership until a few months ago. The problem arose following a period of inactivity of about four months whereby the engine stalls within seconds of selecting forward or reverse gear. I can get it to run a little longer by removing the alternator drive belt but not more than twice as long with the alternator going.
I know this is not an uncommon problem but in this case none of the usual remedies have worked. I have removed cleaned and checked the entire fuel system as far as the injector pump,replaced the filters,bled several times,checked the morse control and cables etc., removed checked and cleaned the exhaust elbow and the Vetus type water trap and the entire exhaust pipe.
I have not had the injectors out because the engine runs very sweetly in neutral,no smoke or unusual noises.
I am now coming round to suspect the governor which is a simple centrifugal type.
Before embarking on a major strip down I thought I would ask the panel for advice or comments.
PS Engine mounts okay.

 

[Baddox]

Is the prop fouled? If shaft drive, can you turn the shaft by hand?

 

[rakaaw]

Is the prop fouled? If shaft drive, can you turn the shaft by hand?

Thank you for mentioning this. The prop turns easily by hand in both directions.

 

[garymalmgren]

The problem arose following a period of inactivity of about four months
Ok. What can happen to an engine that has just sat?
You really seem to have gone through all the proper steps to find the cause.
However I think it has to be fuel.
Start at the tank. Breather tube blocked , creating a vacuum.
Fuel cap vent blocked.
Fuel pick up blocked.
Fuel pick up strainer blocked.
Fuel tank cock restricted.
Put bucket at the fuel cock, disconnect line and run fuel for a while.
Check for water, contamination or restricted flow.
Disconnect fuel line at each component (filters, delivery pump) and check flow before and after each component.
Disconnect fuel line after high pressure pump and turn over engine, check flow.
Bleed at injectors.
the engine stalls within seconds of selecting forward or reverse gear.
This would indicate that enough fuel is getting through to the injectors at low engine speed/load but not enough when the demand is on.
I know that you have been through all this but logically it has to be fuel.

gary

 

[footsoldier]

Just to add to the above - you might be able to confirm that it's a fuelling issue by rigging up an alternative, temporary gravity-fed fuel source (in other words, a can and a hose).

 

[Refueler]

How long does the engine run if left in neutral ? Does the engine rev up in neutral without hesitation ?

Various levels of fuel starvation can lead to engine stalling ... and various reasons for it ..

Crud in tank being picked up by fuel line

Partially blocked fuel line or filters

Tiny air leak in a connection

Air bubble not cleared from injectors / pumps

I've had various engines that started OK - ran ok at neutral for a while - then stopped or died when load comes on ... basically filters etc were full at start - but lack of fuel volume getting through caused starvation when load applied.... engine stalls.

 

[Graham376]

Just to add to the above - you might be able to confirm that it's a fuelling issue by rigging up an alternative, temporary gravity-fed fuel source (in other words, a can and a hose).

I carry a length of fuel hose and a spare can of fuel, just in case. If the OP's engine has a Facet electrical pump, there's a small filter in the base which is often overlooked.

 

[rakaaw]

Thank you for the suggestions. Interestingly I have been through all the steps recommended but not had any success.
Refueler’s reference to tiny air leaks has me wondering and is now beginning to niggle a bit.
I don’t know for sure but I think the engine will run indefinitely in neutral. I have let it idle for about 10 minutes at most. When accelerating from idle in neutral sometimes it hesitates ,sometimes it responds normally. Starting from cold is not quite as good as it used to be but not excessively so.
Another thing I have noticed is that occasionally when stalling in gear there is a puff of smoke from the air filter. Should have said earlier that I have cleaned the wire wool type filter so I know that is not the problem.
This situation has gone on for weeks now and having tried everything in Gary’s extensive list ( thanks for taking so much trouble) more than once and ,in some cases several times I am having to consider even the unlikely things such as the governor. Then again there is the tiny air leak worm which is beginning to wriggle into my thoughts.
When I fuelled the engine from a can I connected to the in port of the lift pump.Maybe I should have directly to the injector pump.
Sorry for rambling.

 

[footsoldier]

When I fuelled the engine from a can I connected to the in port of the lift pump.Maybe I should have directly to the injector pump.
Sorry for rambling.

Probably worth trying in the absence of any other suggestion - certainly connecting direct to injector pump is the only way of validating this test.

 

[Alex_Blackwood]

Thank you for the suggestions. Interestingly I have been through all the steps recommended but not had any success.
Refueler’s reference to tiny air leaks has me wondering and is now beginning to niggle a bit.
I don’t know for sure but I think the engine will run indefinitely in neutral. I have let it idle for about 10 minutes at most. When accelerating from idle in neutral sometimes it hesitates ,sometimes it responds normally. Starting from cold is not quite as good as it used to be but not excessively so.
Another thing I have noticed is that occasionally when stalling in gear there is a puff of smoke from the air filter. Should have said earlier that I have cleaned the wire wool type filter so I know that is not the problem.
This situation has gone on for weeks now and having tried everything in Gary’s extensive list ( thanks for taking so much trouble) more than once and ,in some cases several times I am having to consider even the unlikely things such as the governor. Then again there is the tiny air leak worm which is beginning to wriggle into my thoughts.
When I fuelled the engine from a can I connected to the in port of the lift pump.Maybe I should have directly to the injector pump.
Sorry for rambling.

If you are worried about an air leak, try wrapping a bit of cling film round the joints in the fuel lines, and round the filter(s) see if it makes any difference. If it cures the problem remove wrapping one by one until problem reappears. Might work

 

[oldharry]

A quick way of checking for leaky joints is to clean them off, try the engine then wipe each joint with coloured bog roll. Any fuel present will show up as darkened tissue. Even a trace a fuel will indicate a leak that will suck in microbubbles which will produce the symptoms you describe.

Another more comprehensive test is to plumb a priming bulb like those used on outboard lines into the fuel feed. Makes bleeding much easier, and enables you to pressurise the fuel system. Then try the coloured tissue test.

You might even find that by keeping the pressure on with the priming bulb you can get the engine to run, proving there is a leak.

As above, with an engine that has been left standing, what is to go wrong except fuel supply? The fact that it fires up, suggests there is nothing much wrong mechanically.