Removing Injectors, Perkins diesel

[Solution]

Hi all, I recently purchased a sail boat, and at the very end of my delivery cruise, I ran out of fuel. After bleeding out all the air and changing the fuel filters, I have come to the conclusion that some dirt must be clogging the injectors as it wont fire at all.

I have started trying to remove the injectors in the 4.108 Perkins I have, but can't get them out, I'm hoping that one of you out there knows a couple of tricks for getting them out. Any help is appreciated, thanks!

[John & Jan]

The Perkins 4.107 is notoriously difficult to bleed. You might want to play with that some more first. We added a flow through electric fuel pump (about $50) and finally got enough pressure to bleed her through to the injectors. The little manual pump won't get it past the distributor and "bumping" the starter didn't work well for a newbie like me.

I hope this helps!
John & Jan
SV Santa Teresa

[svHyLyte]

The various manuals for the Perkins 4-108 can be found at Engines Perkins The fuel injectors ("atomizers") are simply held in with two bolts, one on either side of each injector.

Frankly, I don't see how you might have gotten anything into the injectors simply by running out of fuel. Unfortunately, the bleeding process for the 4-108 is not the easiest. Have you managed to get raw fuel--only--issuing from the union between the high pressure lines from the injection pump and the injectors? IF not, you have not fully bled the system.

Good Luck!

s/v HyLyte

[Chief Engineer]

Crack the injecctor lines as they go into the injectors. Crank the engine over untill you get fuel issuing from the nut. It may spurt it may not.

Keep us posted.

There is a bleeder screw on the injector pump...but we aren't there yet

[donradcliffe]

I'm about 90% sure that there is nothing wrong with the injectors, and you just haven't sufficiently bled the engien. Download the 4108 manual from Endeavour Manuals

follow the instructions for bleeding the engine in section N, but be sure to close the thru-hull for the engine cooling before you do a lot of cranking over of the engine, and open it once it starts (to keep from filling the exhaust system with cooling water).

[Chief Engineer]

Depending on the type of exhaust run you have....if you fill it with water the engine will not start.

[GreatKetch]

I'll second, or third, or fourth, that comment about Perkins being tough to bleed. You have to follow the procedure in the manual EXACTLY. Don't skip a step and don't do them out of order or it won't work. Before you start tearing into things, it would be worth tracking down a local who knows how to do this and can show you the "nuts and bolts".

These engines will start and run with just one injector firing, very roughly and with no power, but they will keep turning over. So as others have commented, getting enough dirt into things to totally shut the engine down is highly unlikely. If there is air in the injection pump or high pressure lines, they will not run, not even a little.

Whenever I have to bleed my engine I cuss a lot and get a lot of fuel all over the place.

P.S.: For the 4-154 there is a special tool for extracting the injectors. They are a tight fit, even with the attaching bolts removed, they don't just slide out. If you really decide you want them out, either get the tool, or go very gently and carefully to avoid damaging things. I am not sure if the same is true for the 4-108

[forsailbyowner]

simply remove the hold down bolts, and gently twist and pull to remove. the perkins manual recommends having the injectors pop tested and cleaned every season. I only did mine when I first bought it and havent had problem since. The hardest part of the bleeding procedure Ive found is identifying the injector pump as the bleeder nuts are in different locations. fujiyachts.com has complete manuals online for the m4.108 owners, shop service and parts list. In my opinion if its your boat, you should figure out how to replace, service , bleed everything involved as you will have to do it again eventually and it may not be at a dock.

[Solution]

Thanks for all the recommendations everybody, I was thinking along the same lines that all 4 injectors clogging at the same time was a little far fetched. I have, however, bled this thing out according to the manual several times over now, and have stopped coming accross air a long time ago. I may just try it a couple more times though as the injectors are pretty stuck in there, and I might just get lucky. I may also try the electric pump to get up enough pressure for the injectors to fire.

Thanks again,
Trevor

[lannen]

Chief Engineer speaks wisely...

Look at your type of exhaust. If it's the kind I had, and you keep cranking, it will fill with water. Then the water will go into the engine. Then it still won't start and you have to leave the boat for a while. Then when you get back its seized up. Then you get to go get a new Yanmar.

And boy-o-boy do I like my new Yanmar.

And by the way, my 4-108 injector pump had a small bolt, like 5/64ths or something small and strange like that, on the side near the top. That had to be cracked for bleeding too. I don't remember if that was in the manual or not.

[Chief Engineer]

Did you crack the nuts at the injectors?

An electric pump will NOT generate enough pressure to activate the injector.

Injectors sometimes get frozen/rusted in. PB Blaster and time and gentle tapping and twisting.

The key word is gentle/patience

[ausieman]

OK I know I'm going to get blasted for this one and I pondered for some time as to whether or not to post but anyway here goes. I ran an earthmoving business for 15 years so and one of my plant had a Perkins that was notoriously difficult to bleed. The only reliable solution I could come up with was to put some petrol on a rag (damp not wet) and place the damp area over the air intake (don't let the rag get sucked in). The engine will run on this air fuel mixture (with a bit of combustion knock) and while it's running crack open each injector in turn until a small amount of diesel is seen and then re-tighten. This method is not approved of by any manufacturer but I was taught it by some top class diesel mechanics when working in open cut mines in Northern Australia. I have also successfully used this method to start engines when the battery only had enough charge left to just turn the motor over. Oh yes. it works well in sub zero conditions when the glow plugs have given up the ghost.
I'm now in the process of preparing myself for the howls of protest.

[GreatKetch]

Originally Posted by ausieman

OK I know I'm going to get blasted for this one and I pondered for some time as to whether or not to post but anyway here goes. I ran an earthmoving business for 15 years so and one of my plant had a Perkins that was notoriously difficult to bleed. The only reliable solution I could come up with was to put some petrol on a rag (damp not wet) and place the damp area over the air intake (don't let the rag get sucked in). The engine will run on this air fuel mixture (with a bit of combustion knock) and while it's running crack open each injector in turn until a small amount of diesel is seen and then re-tighten. This method is not approved of by any manufacturer but I was taught it by some top class diesel mechanics when working in open cut mines in Northern Australia. I have also successfully used this method to start engines when the battery only had enough charge left to just turn the motor over. Oh yes. it works well in sub zero conditions when the glow plugs have given up the ghost.
I'm now in the process of preparing myself for the howls of protest.

Sounds like a useful technique to use on an engine owned by someone else :P This is likely safe enough on an engine outdoors BUT... A rag saturated with gasoline in a diesel boat's engine room, where nothing is sparkarrested, is just asking for a disasterous fire. Try this on a boat and you'll get "blasted" all right!

Small Perkins are tricky to bleed, but only because people take shortcuts on the recommended procedure. An engine that could NOT be bled likely has a problem with the injector pump or a poor fuel installation or lift pump.

I have heard (but never tried) that diesels will run on WD40 sprayed into the air intake. That would likely be safer to the engine innards (with less pre-ignition), not to mention the mechanic and the boat, than using gasoline.

[CaptG]

My neighbor used WD 40 to help start his Perkins for more than a year with no ill effects. He eventually fixed the real problem which was injection pump related. In Solutions case it sounds like incomplete bleeding process. On my 4-108 I open the bleed screw on the fuel filter and pump lift pump lever until fuel flows free from filter bleed screw then close bleed screw. Next I open bleed screw on the side of the IP and pump lift pump lever until fuel flows free from bleed screw. Close bled screw and crack 1 fuel line at the injector and crank engine with starter until engine fires (usually about 3 seconds).Will run rough until I tighten fuel line then all is well. The proper process is not difficult if done correctly. Due to engine location and exhaust setup on my boat I don't have the water issues mentioned in other posts.

[lannen]

When bleeding a Perkins I've found that there are as many different answers as there are engines. It seemed that each one had is own 'special' procedure that was specific to the individual engine.

I actually turned to witchcraft once to get mine running.

I did buy a can of spray diesel starter fluid (well, actually 2 cans) and used that with a degree of success. I figured is was safe to use, and really easy to store.