Perkins 4108 Run Away and attempts at fixing - help please!

[HNS4vr]

Hello there fellow boat people - need some thoughts/help regarding getting our 1986 Perkins Diesel 4108 back up and functioning.

What happened and what we've done thus far to fix.

We had an episode w/ the engine "running away" unable to stop via the emergancy kill switch, lots of white smoke out and the scariest 5 minutes of our boating adventures. Engine finally stopped of it own accord, we were safely able to get it back into the slip. We've called our local boat mechanic to fix, but due to a family issues he hasn't been able to complete the job and we have been left to go about this on our own.

What has been replaced/done thus far. Mechanic replaced the fuel lift pump/fuel injector pump. Mechanic left in the middle of replacing those parts, we finished that, tried to start - got it to "barely" turn over one time but no other success. We have replaced the starter motor, since that we determined was also failing. Note batteries are new and have plenty of juice. Drained the oil and replaced the filter. FYI when draining the oil found it full of full as well. remove the injectors, cleaned them they were dry. Tried to turn over the engine while the injectors were off got it to turn over but no catch. We put them back on and engine won't start. We have made sure the engine isn't seized, the fly wheel still turns easily.

We still are stymied on what next to try…


Any suggestions??

[Badsanta]

Fuel leak into the oil. Raising the oil level causing it to be sucked into the motor causing uncontrolled run away. Common leak on a diaphragm lift pump.

[Badsanta]

In my humble opinion

[Shenandoah52]

Did you bleed the fuel system to remove all the air so you have fuel at the injectors?

[stormalong]

Injection pump timing is critical to starting the engine. The workshop manual tells you how to get the timing right.

"while the injectors were off got it to turn over but no catch" - I don't understanding this statement. A diesel engine will never start with the fuel injectors out. From your remarks it sounds like you are unfamiliar with diesel engine basics.

I think you need to get another mechanic.

[skipperpete]

Originally Posted by HNS4vr

Hello there fellow boat people - need some thoughts/help regarding getting our 1986 Perkins Diesel 4108 back up and functioning.

What happened and what we've done thus far to fix.

We had an episode w/ the engine "running away" unable to stop via the emergancy kill switch, lots of white smoke out and the scariest 5 minutes of our boating adventures. Engine finally stopped of it own accord, we were safely able to get it back into the slip. We've called our local boat mechanic to fix, but due to a family issues he hasn't been able to complete the job and we have been left to go about this on our own.

What has been replaced/done thus far. Mechanic replaced the fuel lift pump/fuel injector pump. Mechanic left in the middle of replacing those parts, we finished that, tried to start - got it to "barely" turn over one time but no other success. We have replaced the starter motor, since that we determined was also failing. Note batteries are new and have plenty of juice. Drained the oil and replaced the filter. FYI when draining the oil found it full of full as well. remove the injectors, cleaned them they were dry. Tried to turn over the engine while the injectors were off got it to turn over but no catch. We put them back on and engine won't start. We have made sure the engine isn't seized, the fly wheel still turns easily.

We still are stymied on what next to try…


Any suggestions??

"Stopped of it's own accord" sounds ominous unless it simply ran out of fuel. If it had a serious un governed overspeed there could be severe internal damage but if it was just a wide open throttle incident it should be ok. Did the mechanic get the injector pump overhauled by a tech or just open it up for a peek inside? The bill will provide the answer, if it's around a 500 to $1000 that's an overhaul. The Perkins pump is easy to install because it has a master spline on the drive that only permits one position initially then small corrections by rotating the entire pump.
These DPA pumps can be a pain in the neck when it comes to bleeding off the air so put the injectors back in , reconnect the hp lines, check the timing mark on the base plate of the pump with the scribe line on the engine block( they should roughly line up) open the two bleed screws on the injector pump body and the bleed screw on the fuel filter that's on the pressure side of the lift pump.......manually rotate the engine to the point where the manual lift pump will operate and start pumping.
As clear fuel ,free of bubbles is observed at each bleed screw, close it off gently......then loosen the injector lines at the injectors , make sure the engine stop lever is in the run position, throttle above idle position , raw water intake shut off and the battery fully charged. Operate the starter for 5 seconds and re bleed the injector pump twins again if no fuel is seen at the injectors. Try the starter again for 5 seconds and in a perfect world you should see fuel at the injector connections.... if so tighten the pipes and try another 5 seconds with the starter and be ready open the sea cock and to operate the throttle or shutdown.
It's good practice to be prepared to block the air intake and open the hp pipes if she tries to run away again.
Good luck. Pete.

[stormalong]

One more thing: Never put your hand over the air intake of a runaway diesel engine. No personal experience but the word is that the suction will pull the skin right off your hand.

[skipperpete]

The highest vacuum pressure possible is -14.7 psi and depending on the hand I guess that's possible but my engineers kangaroo paws remain intact after several runaway interventions over the years. It takes a leap of faith to do it and I definitely don't suggest you try it but once way back in the days of old time mechanics it was common practice to " palm of hand" choke petrol engines to get them going. I have no idea how much vacuum a runaway engine actually pulls but I know for sure I can stop a 4JH Yanmar at around 4000rpm.

[GordMay]

Greetings and welcome aboard the CF, HNS.

[rmlarson1098]

Originally Posted by HNS4vr

Hello there fellow boat people - need some thoughts/help regarding getting our 1986 Perkins Diesel 4108 back up and functioning.

What happened and what we've done thus far to fix.

We had an episode w/ the engine "running away" unable to stop via the emergancy kill switch, lots of white smoke out and the scariest 5 minutes of our boating adventures. Engine finally stopped of it own accord, we were safely able to get it back into the slip. We've called our local boat mechanic to fix, but due to a family issues he hasn't been able to complete the job and we have been left to go about this on our own.

What has been replaced/done thus far. Mechanic replaced the fuel lift pump/fuel injector pump. Mechanic left in the middle of replacing those parts, we finished that, tried to start - got it to "barely" turn over one time but no other success. We have replaced the starter motor, since that we determined was also failing. Note batteries are new and have plenty of juice. Drained the oil and replaced the filter. FYI when draining the oil found it full of full as well. remove the injectors, cleaned them they were dry. Tried to turn over the engine while the injectors were off got it to turn over but no catch. We put them back on and engine won't start. We have made sure the engine isn't seized, the fly wheel still turns easily.

We still are stymied on what next to try…


Any suggestions??

A bit off topic maybe, but as I understand it a true 'runaway' diesel will not stop by shutting off the fuel supply. (?) We carry - but have never used - a 'plug' for the engine air intake. As it was explained to me, in runaway mode the diesel will burn up its own engine oil and destroy itself if not stopped, even after shutting off the fuel supply. A fire is another real possibility. So eliminating air for combustion would be the last solution for getting the beast stopped.
Any motorheads out there want to chime in? Thanks.

[Cadence]

Originally Posted by rmlarson1098

A bit off topic maybe, but as I understand it a true 'runaway' diesel will not stop by shutting off the fuel supply. (?) We carry - but have never used - a 'plug' for the engine air intake. As it was explained to me, in runaway mode the diesel will burn up its own engine oil and destroy itself if not stopped, even after shutting off the fuel supply. A fire is another real possibility. So eliminating air for combustion would be the last solution for getting the beast stopped.
Any motorheads out there want to chime in? Thanks.

I carried a weather gear">foul weather gear jacket to cut air off to a worn out JD350 dozer.
Sucking sump oil is a reality. The post about fuel getting into the sump sounds
realistic with white smoke not black.

[stormalong]

Originally Posted by rmlarson1098

A bit off topic maybe, but as I understand it a true 'runaway' diesel will not stop by shutting off the fuel supply. (?) We carry - but have never used - a 'plug' for the engine air intake. As it was explained to me, in runaway mode the diesel will burn up its own engine oil and destroy itself if not stopped, even after shutting off the fuel supply. A fire is another real possibility. So eliminating air for combustion would be the last solution for getting the beast stopped.
Any motorheads out there want to chime in? Thanks.

That is correct. A runaway engine is burning oil from either a turbocharger oil leak of oil from the crankcase from it being overfilled or filled with diesel fuel from a fuel pump diaphragm leak.

[stnick]

Perkins 4108 has run away on me . I used a board to choke the air after removing the air filter cap . Has to be done fast you cant allow a run away engine to continue. Stop right away ! I had my fuel pump replaced Than had to blled the injectors of air she would not start.
I used starter fluid And I was not suppose to . But it worked and i have not had any trouble now in 2 years !!

[Wulf]

Have you cut open the oil filter to check for metal on the paper? Squeeze the oil out of a section of the element, then pull it apart and look between the pleats. Black oil will have been squeezed out, metal flakes, bits etc will tell the story if present. Also check if magnetic or not,then discuss with someone you can trust. That should always be a first step any time you’ve had a “runaway” that exceeded max governed rpm. Btw, its not a runaway if it just goes to max rpm or something less.

As an aside, if you have maneuvering room and someone at to grab the helm when a runaway occurs do NOT put it in neutral. Assuming it’s already in gear, leave it as such, assign someone to the helm and choke off the air intake ASAP. Do not try to put a runaway engine in gear if it’s in neutral. Any book, cutting board etc will suffice. Also I’m not a fan of trying it with your hand, why risk it?

[zeehag]

mine played runaway diesel in 2013, hence the thread bearing name ka lunk. read it.. enjoy it. and enjoy your rebuild.