Can Diesels run rich?

[davel]

Just had an embarrassing experience - I ran out of diesel !

I have a 33 ft sailing yacht with a Yanmar 2GM. By my calculations I should have had enough fuel for another 6 hours running - but I didn't!

The engine cut out suddenly so I dropped anchor and looked below to try and find the cause. I discovered two things a) I was out of fuel and b) there was an old sock stuck in the air inlet!
I reckon that the sock was left in after the winter layup and I'm postulating that the engine had been running rich because of this - consequently using quite a lot more fuel than usual. Does this sound feasible?

 

[Bejasus]

starved of air/running rich = smoke you would notice.

 

[Saddletramp]

No! Got you on two counts now. You just have to accept you cocked up.

I did a couple of weeks ago. Ran out of fuel, no problem plenty of wind, 10 mins later that died as well. To cap it all we were on our way to the Forum Mercury Meet. At least my good friend waited a good 5 minutes before proceeding to relate the whole sorry episode to anyone who would listen. /forums/images/graemlins/tongue.gif

 

[steve28]

Reducing the air intake will make the fuel rack open more as the govenor trys to compensate. So yes but we are only talking a small diffrence over a long time.

 

[philip_stevens]

2GM = 20hp?
1.5ltrs an hour?
6 hours fuel = 9 ltrs?
or 1ltr an hour = 6 ltrs?

That's cutting it a bit fine, allowing for a slight miscalculation of hours run, and unusable fuel at the bottom of the tank.

The sock in the intake would have given you blackish smoke.

A slightly fouled prop would have put up your consumption.

 

[davel]

Thanks for all replies.

Philip, I was being rather simplistic in my statements. I have a 55 litre tank and I typically get about 1.5 litres per hour as you suggested. I usually fill up after about 25 hours running to avoid running close to empty.

This time I ran out after 19 hours running - hence the 6 hours statement in my original post.
When I refilled the tank it only took 44 litres suggesting that 10 litres is unusable (perhaps below the tanks fuel outlet).

Anyhow, it looks like I've been using 2.3 litres per hour with the sock in the air intake (approx 50% increase in consumption).

 

[philip_stevens]

and with that increase in consumption, I would have been certain you would have had black smoke and noticed it.

Most odd, unless the prop is fouled and you have been giving a few more revs to keep up speed.

I must admit to be blasé about fuel consumption, as we have a 50 gallon tank!!

 

[davel]

My exhaust outlet is on the transom, just above the waterline so when underway it lies pretty well on or just under the water surface so if it was smoking I wouldn't really have noticed it. I did spot that the transom seemed to be a little blacker than usual - but only when I was looking for the reasons the engine had stopped ! /forums/images/graemlins/frown.gif