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

[sailorladd]

I am not a diesel mechanic.... but something similar happened to my Yanmar single cylindar many years ago, and it was after a mechanic friend had done some work on the engine...It was also one of the scariest moments of my sailing life! I found out afterwards that when I was heeled over and had my engine running, it started sucking up sump oil from the sump breather tube, and was running, ungoverned of sump oil... Fortunately I recalled reading about similar in a book before this incident, and the best thing to do is starve the engine of its air... stuff a large rag or pillow or something into the air intake, and that should stop it pretty quickly..

I since had the problem solved and as I recall, the mechanic had forgotten to put back some oil baffle or something...it never happened again, but I am wondering if perhaps you didn't blow a head gasket and that is why your engine is not starting?? Check your sump oil for traces of water asap, that is NOT what you want there, especially salt water! Good luck.

[exMaggieDrum]

We have a Perkins 4108, circa 1981, with about 7000hrs. Runs great but has black smoke from an over-pitched prop (can't make rated RPM either).


But the story for this thread is restarting after filter changes or, in my case, running out of fuel (dump thing to do and another story). So I had to put in my spare jug of diesel and then spent hours trying to get it bled. Got it running. I am now a semi-expert in bleeding the beast and can do it chop chop when I service it.


However, after a winter and not used, I re-bled it and it just would not start. I tried everything and it all seemed to be done right. I asked a mechanic friend of mine to come down to assist. He said "don't do anything and I will try to start it". I didn't think he would have any luck but he just cranked it for way longer than I would have and then it started and ran fine. I had already closed off the raw water to keep from filling the waterlift muffler which I turned on as soon as it started.


Moral of the story - sometimes, at least with the Perkins, you need to crank it longer than you think it should after trying everything else. My start battery was new and the starter was a new rebuild. And I had rewired it with bigger cables too. So it had plenty of juice and the starter didn't melt down. I was very sheepish but happy he got it done.


I think there would be a point at which you would quit cranking the motor over but it is longer than I thought, at least for this one time. It normally starts quickly.


P.S. having a board/paddle in the engine room ready to put over the air intake is a good idea in the unlikely but possible case of the engine goes in to runaway. I keep all the tools for bleeding in a shaving kit bag hanging in the engine room along with some oil sorbs to quickly bleed the motor if needed.

[Oceanconcepts]

I have a Perkins 4-107, circa 1970.
re. starting, the prior owner installed a diesel rated bulb type pump, similar to what would be on an outboard, between the primary and secondary filters. In addition to making bleeding after changing filters much easier, a few pumps seems to help get things started right away.

[Shaneesprit]

It worries me that your trying to fix this but seem know so little.
The injector pressure can kill you, ok so it’s an older engine but still, when you say you tried to start with the injectors out that’s ok, but to expect it to do any kind of firing is impossible ( will accept that you might not of meant what you wrote ) Note never ever connect the injector pipe to the injector without the injector tight in the engine!
Also a modern diesel fuel can take your fingers off or worse if you even slacken the wrong fittings.
Ok so now to try and be at least a little helpful,
You were there when the engine stopped, so did it stop with a bang? Slowly grind to a halt?
You cleaned the injectors yourself? How what actually did you do this is a specialist job, if they were not taken to a rebuild specialist, then get them tested.
You fitted the injectors yourself did you replace seals?
Someone suggested Easy start - good shout, turn off the fuel first. ( have the injectors in place, this can give a clue to the mechanical damage if there is any inside, don’t use a lot of easy start as it’s very flammable and can send the engine to runaway speeds - if it doesn’t fire on easy start and the compression has gone, if it does start, then try the same easy start with the fuel on, if it doesn’t start and the injectors are tested - compression check timing check - rebuild
have changed the oil? If not do so as the first job, use cheap oil but the correct type - as it might be that you will have to do a rebuild

[GrowleyMonster]

Originally Posted by Ya Ubetcha

Had the same problem. Luckily we got it shut off quickly. A close examination revealed the rotating fuel shutoff lever was raised up higher than normal. Apparently that allowed ungoverned fuel to flow underneath it. I was able to push it down into place and very nervously travel three hours to a place at a dock where I could remove the fuel injection pump and have it fixed. Expensive fix $750. They replaced worn parts, and assisted in installing it. They say the shaft lever was bent. Now the engine runs much better. Unfortunately that ruined my excuse to remove the engine and replace it with electric drive.

I own an electric boat and a diesel. Electric is nice but if you run your engine more than an hour or so, you are better off with the diesel if you can get it running reliably.

[gruffa]

I had a runaway experience with my 4108 several years ago.
I was motoring in a calm when the engine started to surge, like it can do when being starved of fuel. I pulled the stop lever but it didn't die, it kept surging and revving higher each time before coming back down again, very erratically. I thought it would soon give up but instead it kept going higher each time until it was way beyond any sound i had ever heard it make. I can't remember if I looked at the guage. It was just getting way too scary. Frightening in fact.
Fortunately I had read about how to stop a runaway in Nigel Calder's book. I raced below and whipped the cap of I had a runaway experience with my 4108 several years ago.
I was motoring in a calm when the engine started to surge, like it can do when being starved of fuel. I pulled the stop lever but it didn't die, it kept surging and revving higher each time before coming back down again, very erratically. I thought it would soon give up but instead it kept going higher each time until it was way beyond any sound i had ever heard it make. I can't remember if I looked at the guage. It was just getting way too scary. Frightening in fact.
Fortunately I had read about how to stop a runaway in Nigel Calder's book. I raced below and whipped the cap off the air intake and stuck a cutting board over the inlet and it stopped almost instantly.
One other fortunate thing was that the cap on the air intake was easy to remove without tools.

The engine had been making such a racket that I was sure it would be broken internally.
There was oil spewed all over the engine compartment.

I wasn't able to do anything more at the time as we were being swept towards rocks and the water was too deep to anchor. No wind remember. Flat calm. Anyway, we did get on the rocks, only by a matter of a metre or two..but that's another story.

When I eventually got to examine the engine, I found that the case was full of oil, or an oil/fuel mix actually.
Suspected a fuel pump leak. Removed the lift pump and examined but could find no fault in the diaphragm. I left it off and replaced that element with an inline electric pump. I always hated bleeding with that lift pump anyway.

Removed the injector pump ( with great difficulty) and had it serviced.
Got that back in and the engine bled and it started and runs fine now.

Incidentally, I have much frustration getting the bleeding done. It always seems hard to get the final bit done. I use WD40 as a starting fluid, as recommended by Nigel Calder. It's much less harsh that Ether types of starting fluid. It doesn't makes the knocks that Ether does. You can spray it in while someone presses the start and it will run on the WD40 and bleed that last little frustrating bit til the engine kicks.

[Wotname]

Originally Posted by Shaneesprit

It worries me that your trying to fix this but seem know so little.
The injector pressure can kill you, ok so it’s an older engine but still, when you say you tried to start with the injectors out that’s ok, but to expect it to do any kind of firing is impossible ( will accept that you might not of meant what you wrote ) Note never ever connect the injector pipe to the injector without the injector tight in the engine! ........

And yet some service manuals suggest this is a good way to check the spray pattern. Remove injector from the head, leave it attached to the injector pipe, ensure the nozzle is pointing away from you (and keep your hands well away from the firing line) and rotate the engine and observe the spray pattern.

[Compass790]

Originally Posted by Wotname

And yet some service manuals suggest this is a good way to check the spray pattern. Remove injector from the head, leave it attached to the injector pipe, ensure the nozzle is pointing away from you (and keep your hands well away from the firing line) and rotate the engine and observe the spray pattern.

Shaneesprit also said you cannot overload an engine with a propellor
Buyer beware!

[skipperpete]

Originally Posted by Wotname

And yet some service manuals suggest this is a good way to check the spray pattern. Remove injector from the head, leave it attached to the injector pipe, ensure the nozzle is pointing away from you (and keep your hands well away from the firing line) and rotate the engine and observe the spray pattern.

Diesel mechanics do this injector test quite often, great diagnostic tool, but the problem is that the level of engineering skills of the cruisers and yachtsmen that post on the forum is highly variable. Some folks/cruisers could do tests like this easily and as competently as any pro but others shouldn't even be in the machinery space while the engine is running.
My car has a warning plate next to the engine " DO NOT ATTEMPT TO ADJUST OR CHANGE BELT WITH ENGINE RUNNING"
Just sayin!

[Wotname]

Originally Posted by skipperpete

Diesel mechanics do this injector test quite often, great diagnostic tool, but the problem is that the level of engineering skills of the cruisers and yachtsmen that post on the forum is highly variable. Some folks/cruisers could do tests like this easily and as competently as any pro but others shouldn't even be in the machinery space while the engine is running.
My car has a warning plate next to the engine " DO NOT ATTEMPT TO ADJUST OR CHANGE BELT WITH ENGINE RUNNING"
Just sayin!

This is all true and I concur yet when a member requests help on CF, I think it is incumbent to provide an accurate response as far as possible without dumbing it down to the lowest denominator. There is an educational aspect inherent in many replies and this is helpful not only to the OP but to other readers who don't post.

I guess I took objection to the "never ever" content of the mentioned post when this is clearly not the case and could prevent others from expanding their knowledge base. IMO perhaps better phrased as "never ever unless you you know or be willing to educate yourself of the risks etc".

And for sure, if there is some danger then the appropriate warnings should be included.

[Compass790]

Very good reply Wottie,
I tend to assume people have more mechanical skill than they often do so the safety aspects get neglected which skipperpete was right to point out.
But I'm glad you corrected the misinformation re checking injector spray pattern on non-common rail engine.
I couldn't have put it nearly as well myself.