Runaway diesel, black fuel in return line

[zeehag]

are these related?

how did the fuel become black? it went in clear.

about hour 40 of a nice 80 hour bashing motorsail from zihuatenejo north to barra de navidad, which should have taken only 40 hours, we discovered there was a huge dump of black almost carbony looking stuff from wet exhaust, and much black smoke, no blue tinge from obvious oil--just plain ol black smoke with higher rpms.

we get into barra and all seems well. oil has been changed and engine is fine. starts right up and no smoke.... awesome iron kitten.

we go to pull up anchor-- engine is running-- as windlass electric pulls the rpms rise... remarkably lots--- ok....ok... ok, now is scary... still rising.

cracked all injectors as the fuel all stop didn't kill the engine. and when injectors were cracked and no compression any more, blessed silence.

the entire event took less than 5 minutes from onset to silence, and no detonation or overheat.
whew.

so......

splain me loosey....what hoppened?

yes I know, runaway diesel, but what actually made fuel black and all that black stuff and smoke and why runaway? could these two incidents which occurred so close in timing, be related, or is there a salad of pandoras box i need to discover yet?

 

[centerline]

im going to suggest you have a blown/burnt turbo seal.... its letting engine oil into the intake and the exhaust and causing all of the problems.....its about the only thing that would cause all those symptoms together.....

 

[Merlin Clark]

I think it was either over filled when the oil was changed or bad rings.
I don't know any old sailboat engines with turbos.

 

[centerline]

I think it was either over filled when the oil was changed or bad rings.
I don't know any old sailboat engines with turbos.

and i thought that when i posted.... and an overfilled crankcase could do that too, but as i understand it, he changed the oil in the engine and it did it again..... so it would make one wonder how is it sucking the oil up out of the crankcase if he got it right the second time....

UNLESS.... there is another problem and diesel being pumped into the crankcase and filling it up to where its getting to the cylinders....

not sure of the engine model, but a bad transfer/lift pump seal could do it very easily...

 

[zeehag]

perkins 4-108
manual lift pump augmented with a electric assist pump which doesnt shut off without the key

aint got turbo......my Z car did, long time ago, but no on snuck one onto my perkins...


i dont leave port without my mechanic ...... just in case.....

 

[woodster]

check your breather tube that goes the the air intake and see if you fine that black stuff in there if so back track all the way to the crank case and see if you have too much oil in there if so you either have put to much oil in or you may have a fuel leak going it to the crank case....oh and the next time you have a runaway like that heaven for bid ....block off the air intake and starve it from air that will stop it in short order....dont use your hand to block the air intake..... use a finder ......

regards

woody

 

[zeehag]

mchanic was on board and cracked all injectors silenced beastie...event lasted less than 5 minuets and engine did not overheat nor detonate.


bubba was not happy

we willbe tearing down in a weeks time or so--will do pix of the repairs

 

[GeorgiaBII]

Engine will run on oil. I'd check the crankcase vents to see if they are clogged.

 

[Benny17441]

Check your oil for level and viscosity. A fuel leak into the crankcase will elevate the level as well as thin the oil. A thin mixture of fuel and crankcase oil can be easily pushed through the rings into the combustion chamber. The likely culprit can be a perforated diaphragm in the lift pump. Black smoke at higher RPM is a sign of engine overfueling due to a blocked exhaust or fouled prop. The two incidents are compatible but the causes for each are largely unrelated and each will require it's own fix. Check the throttle mechanism and make sure it is not sticking. Lastly, the proper and safest way to turn off a runaway diesel, like others have indicated, is to block off the air intake thus starving the engine. Remove the air filter case and press a large and heavy rag against the intake, do not use your hand.

 

[Morgan donor]

Your mechanical lift pump is leaking into the crankcase.

 

[kloudie1]

Scary, Zee.. I think (kinda like others) that electric pump is pumping fuel into the crankcase through a leaking diaphragm in the mechanical pump. Don't know why oil in return is black .. could be that as the fuel started coming from intake instead of injectors, the governor cut back a lot and the lack of flow on return let it stagnate some and pick up blackness from hose/injectors?? I dunno.
I see that engine has a hydraulic governor .. that should be checked carefully for correct operation and seals not leaking.
A ganged compression release is your friend in cases like that!
Interested to hear what yall find.

 

[Sailor_Jeff]

1. Would love to look at the return fuel that was black under a microscope. But a perkins should have an emergency shut down like all diesels. .
2. A butterfly door over the air intake. You pull the handle and the door closes shutting off all air to the engine.
3. With black fuel on the return side, could there be a fungus growing in the fuel pump? Again a microscope would tell. .
4. Please keep us posted, as I have a Perkins too (in a project) and this could happen to me one day. .

 

[Mac Smith]

I am wondering if the 80 hours of bashing caused algae in the fuel to block the fuel return, causing the run away, which built slowly. He changed oil, and no problems were indicated there. If the bypass was blocked, the provided fuel flow had no where else to go. Just a theory, since the oil was replaced, assumably at the proper levels.

 

[skygazer]

Zeehag, I'm no mechanic, I just want to express my regrets that you are having engine problems. Hope you are able to rea$onably repair and return to sailing, sailing is how I like to picture you in my mind!

 

[zeehag]

no algae in fuel. was brand new and stuff doesnt grow here as well as in temperate zones where condensation in tank is a problem. we dont even have ability to purchase biobor or other anti algae stuff, as no one here gets that....in san diego , yes--here--no--
water and air are nearly always same temp. no condensation.

i usually only fill tank when i prep for underway--we dont keep fuel in tank when sitting.

i used bio bor in san diego--my bottle of it went ob when my mexican helper was sailing from ensenada to mazatlan..lol...aint none in mexico this far south. i think it went deep six with the chubasco we were hit by just north of cabo--

the fuel bugs i have seen have been orange to red....this was stone black with gunk coming from exhaust while under way, at mid point of our 80 hour trek. was a bash with not too much swell. with current and wind against us we were able to accomplish all of 1.8 kts and up to almost 2.1 kts over ground.....kinda like 4 kts to 3.5 if with current and winds....

i think i can rule out bugs


unless this totally depletes my limited income for 6 months, which i am sure it will, as i think we may have to overhaul this beastie, i should be underway again by just after christmas---hopefully with fingers and eyes crossed--if it is more time and money than i can do this season, --may be by next summer i can hop down coast--between storms...

 

[Terry in Naples]

I had this happen to me once coming from key west to naples. A gasket let go and fuel mixed with the oil causing it to get unlimited fuel. Same scenario. My son in law is a mechanic and he drained the oil and scavenged oil from old supplies on board put it in motor and we were able to restart and limp in. wind gusty on the nose at about 15 -20 or so so we were motorsailing in rain and stormy weather. Replaced fuel pump and gasket to fix it back at home. Scared us at the time. I was middle of the night in very bumpy conditions.

 

[zeehag]

terry--is scary when in a calm daylight filled anchorage--the potential is so terminal....

fortunately runaway isnt that common...also unfortunately....

but--


so......

as far as someone with a perkins project--make sure all your sender are present and accounted for, all gauges function and have redundancy -- my second set of gauges is just over the engne doghouse, the primary set in cockpit.

stock upon spares--and hoses!!!!! and carry a rebuild kit for later-they are dear....

because my tank is too small for boat,only less than 50 gal, when boat spozed tohave 120!!!!,we been constantly into the tank--no bugs no dirt....fuel pickup has been problematic for the duration of engine longevity in boat....so we have done some alternative fuel delivery methods..lol..
entered zihuat bay in darkness with less than 2 ounces remaining in racor...lol..nothing in tank or bucket we used as a spare tank...we dun gud..lol
exited zihuat with brand new clean clear fuel....including my 4 jugs on deck....was half way to barra when mechanic found black return fuel---remember i has formosa so it takes twice as long to get anywhere ..lol--so 80 hours for 200 miles is a lot of time--we had issues..like bashing uphill in a formosa...
all fuel has been new each leg of journey....

 

[kloudie1]

Zee, found this link for your records..again.. good luck and sorry to hear.
http://www.bluemoment.com/manuals/Lucas CAV DPA injection pump instruction book.pdf

 

[l turn9]

When a diesel runs away the rpm's get so high it pulls oil past the rings and that keeps the engine running until it kills itself. The cause of the runaway condition requires a detailed look at the engine...

 

[l turn9]

You might be able to find a good used engine for less than the parts and labor needed to repair yours -- you should look at that possibility before you get partway into a rebuild only to discover how expensive "while we're in there-itis" can be... Good luck -