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Blue Stocking · 22-07-2013, 04:48

Zee, check that the liner in the fuel return line has not deteriorated from ethanol or such, and is slowly dissolving the hose matrix, neoprene or such. have seen this twice with older fuel lines.

sartorst · 22-07-2013, 05:48

I with B Stocking on the fuel lines I have seen this many time,as far as the black carbon from the exhaust I have experienced that also and it was from long periods of low load/rpm runs, like motor sailing ,every so often you should push it pretty hard to clear that out or your next post will be about engine knock!are you over pitched(prop)as to the run away part I am not familiar with the Perkins,seen many but not worked on,just keep in mind that a diesel will run just a well on oil as fuel if there is no major engine noise or smoking prior to the runaway event I would be looking into oil dilution from fuel,lift pump first injection pump next

zeehag · 22-07-2013, 06:37

first thought we had was fuel lines and we set out to look for new ones......then as we were seeking fuel lines, a thought like a lightbulb came onin mechanics head.... he didnt speak that thunk..is still keeping it safe...
he changed fuel and filter when we got to lagoon. oil was changed when we got to lagoon.. in lagoon after changing is when we had runaway.

i been thinking is it time for overhaul----lol--and i found a good guy for injector pump building, which he is certain isnt necessary but is good to find anyway....

i still figger we need to do overhaul..and prolly will have by time we done with this adventure...

and now after over 30 yrs of this kind of work, he says he hasnt seen this scenario in any other boat....oboy i am so lucky...... we see what it is--will post pix of repair....
cruising really is fun...so are the repairs....

hellosailor · 22-07-2013, 11:28

Thinking on it overnight...If the black contamination is from carbon-loaded oil somehow getting pushed back into the fuel, that would indicate two failures in a cylinder. One failure allowing the oil to get in (i.e. bad rings) and a second failure (open or grossly mistimed injector) allowing the oil to get pushed back up into the fuel lines.

So a compression and leakdown test (air pressure or traditional kerosene) would work to check the question of the rings. Plus a check on oil level to see if it is coming or going. More problematic would be the injectors. If you have electronic ones, you cna manually trip the solenoid to see if they are functioning. If you have traditional mechanical...not so simple. And that still leaves the question of gross injector timing, but I've never heard that even suspected as being a possible way to force oil into the fuel lines.

What you could do, is to buy some UV trace oil. This is a half-ounce bottle of plain mineral oil with a fine fluorescent powder in it, used in AC systems and engine oil to make your entire oil charge glow. If you put the UV dye in the engine oil, let the engine run for a short while, and then find the diesel fuel also glows under a black light--you've just confirmed that your engine oil is being pushed back into the fuel, and the only question is exactly where or how.

That's a low-tech test, any AC shop will have the black light and dye. Engine shops, not unless there's a geek on staff.

Cheechako · 22-07-2013, 11:57

check to make sure the runaway isnt from fuel in the oil. I didnt have a runaway because I caught it, but had a similar problem with a perkins 4-236.... turned out to be a fouled injector (likely from sitting too long) spewing fuel into cyl #4 and putting 1.5 quarts into the crankcase in 8 hours use! Engine seemed to run fine without that cylinder! but it was spewing back stuff and oil all over the water.... took my mechanic a few days to zero in on this.... compression showed bad #4 cylinder.. we were about to pull the engine (after rebuilding injectors) when he said " I want to check that cylinder one more time"... the cylinder came back fine... same compression as the others... turns out after the injector quit washing out the cylinder with fuel , the rings seated back fine....

Fuss · 26-07-2013, 03:19

Quote:

Originally Posted by zeehag

first thought we had was fuel lines and we set out to look for new ones......then as we were seeking fuel lines, a thought like a lightbulb came onin mechanics head.... he didnt speak that thunk..is still keeping it safe...
he changed fuel and filter when we got to lagoon. oil was changed when we got to lagoon.. in lagoon after changing is when we had runaway.

i been thinking is it time for overhaul----lol--and i found a good guy for injector pump building, which he is certain isnt necessary but is good to find anyway....

i still figger we need to do overhaul..and prolly will have by time we done with this adventure...

and now after over 30 yrs of this kind of work, he says he hasnt seen this scenario in any other boat....oboy i am so lucky...... we see what it is--will post pix of repair....
cruising really is fun...so are the repairs....

From these posts, there was no fuel in the oil, the engine had just had an oil change and the engine had previously been smokey with black stuff in the water.
So it has alot of hours on it as oil is getting past the rings.
If you know how many hours the engine has, then this would be good for us to know.

Maybe what happened is that after the oil change, it was slightly fuller than usual (maybe overfull) and this was just enough to set off the runaway condition.

If it was not overfull, then I would suggest running the engine on a slightly lower oil level and it might extend the life some. By extending the life, I mean it might not runaway again. The runaway condition is the reason you now want to do a rebuild.

It doesnt solve the smoke and black stuff in the water, but when you are running on a tight budget with a big boat, this might save you some money.

zeehag · 26-07-2013, 05:49

hours on engine--2500 milesX3.5km per hour= hours on my engine, since install 2009

Sailmonkey · 26-07-2013, 05:53

Quote:

Originally Posted by zeehag

hours on engine--2500 milesX3.5km per hour= hours on my engine, since install 2009

Wasn't it a used engine when you installed it in '09?

zeehag · 26-07-2013, 05:54

yes shipped from michigan to me...

Sailmonkey · 26-07-2013, 06:01

Quote:

Originally Posted by zeehag

yes shipped from michigan to me...

So in essence, you don't have any idea.

zeehag · 26-07-2013, 06:15

absolutely none, other than what i have done to it...is why i dont mind doing overhaul .

Redcoat · 26-07-2013, 08:29

Have you tried running clean diesel from a jerry jug through it? I have never heard of this scenario but if it is carbon sounds like a lot of it. If no work has been done to the fuel injection pump I would try flushing it with clean diesel at the dock by running under load. Over fueling would cause black smoke but a sheen on the water would suggest a carbon coated valve. What kind of blowby out of the oil cap.

zeehag · 26-07-2013, 17:33

when we got to barra lagoon we changed oil and we changed fuel and placed black fuel into a jerry jug and put new diesel into tank and changed all filters.
after we did this , and we were going to go from lagoon into marina, about half mile away,while raising anchor the engine ran away. everything was new.