New injectors v rebuilding injectors

[Pirateking]

My 3 cyl Westerbeke 7.9 kW diesel genset will not fire. At all. This is NOT a bad sensor because it will not fire with start switch depressed, nor will it fire with a little either, according to a "new to me" mechanic. Mechanic saying probably injectors,mane that he has a set he had rebuilt for one of his similar engines, and he will just put those in.

I am hesitant to rebuild to begin with, and more hesitant to take a set that I don't really know anything about. He is saying about $30 apiece, ?

I could use some experienced advice, I have never had to replace injectors.



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[undercutter]

Sounds like no fuel but how do you know it is not the injector pump? Did you crack the fuel lines at the injectors to see if you have fuel there? Could just be a bad lift pump as well. Could also be waterlocked. Too many things to just start changing injectors.

How old is the gen set. How many hours?

Maybe you should get a 2nd opinion.

[Sailmonkey]

If it won't fire with ether it's not injectors.....by feeding fuel into the intake you don't need injectors


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[undercutter]

Injecting ether into the intake manifold and thus the combustion chamber has nothing to do with the injectors and as such is no indication as to whether the injectors are good or not!!!!!!!!!!!!!!!!!!!!!!!!

[a64pilot]

well I doubt $30 a piece and won't "fire" with either isn't injectors, No fuel at all, it will fire with either, rattle like hell and stink, but it will combust if there is compression.
Find another mechanic


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[model 10]

I just had our injectors sent in for service. They have all these tests for when they open and how much pressure it takes to open and the spray pattern etc.. It's easier for them to just sell you overhauled injectors than to do your injectors individually if yours are no good.

[Sailmonkey]

Everybody forget about the damn injectors!!!!!!!!
the op said the engine won't fire with ether sprayed into the intake......I don't care how f'd up your injectors are.....the engine should fire from the ether. This is not an injector problem.


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[model 10]

Originally Posted by Sailmonkey

Everybody forget about the damn injectors!!!!!!!!
the op said the engine won't fire with ether sprayed into the intake......I don't care how f'd up your injectors are.....the engine should fire from the ether. This is not an injector problem.


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Sure but if a diesel won't fire with ether, what the hell? Maybe somebody took the pistons.

[Sailmonkey]

Originally Posted by Guy

Sure but if a diesel won't fire with ether, what the hell? Maybe somebody took the pistons.

Or the valves are stuck....etc.

How long has it been since the engine last ran. How many hours are on it, how old is it, has it been water locked? Are the cylinders glazed or the rings stuck?


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[jimbunyard]

All of the above, but also make sure your electrical system is ok. Insufficient starter speed can make a diesel hard to start. Check all connections, but pay close attention to the high amperage ones, both positive and ground.

[DumnMad]

Originally Posted by jimbunyard

All of the above, but also make sure your electrical system is ok. Insufficient starter speed can make a diesel hard to start. Check all connections, but pay close attention to the high amperage ones, both positive and ground.

Yes could also be starter coil issues.

[Pirateking]

Mechanic said that if injector was stuck open, no compression, would push back down injector. To me, that's a lot of pressure to go backwards down a little nozzle. We have replaced the lift pump, fuel to the injectors.


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[Sailmonkey]

Originally Posted by Pirateking

Mechanic said that if injector was stuck open, no compression, would push back down injector. To me, that's a lot of pressure to go backwards down a little nozzle. We have replaced the lift pump, fuel to the injectors.


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IMHO there's no way you're going to lose enough compression through a stuck injector to fire on ether.

I just can't see all of the injectors sticking at the same time either.

When did this engine last run?


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[undercutter]

Originally Posted by Pirateking

Mechanic said that if injector was stuck open, no compression, would push back down injector. To me, that's a lot of pressure to go backwards down a little nozzle. We have replaced the lift pump, fuel to the injectors.


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Absolutely, not possible that the cylinder is losing enough compression through the injector to misfire. More likely this would result from bad valves, rings, etc. Not to say that any of this is the problem.

You are certainly not providing enough information for anyone on here to be able to help you or even want to. The questions are;

How fast is the engine turning over when you try to start it. Does it seem normal or slower?

Is the fuel at the injector connection adequate or does it seem minimal? Do you or the mechanic have enough experience to know?

Everything being the same as it was prior to the failure then the engine should fire on ether for sure and would only quit if there was a problem with fuel delivery or air delivery to the system. I can tell you this for sure as I am sitting in Darwin waiting for an injector pump from England to replace the failed unit on the main engine which we lost just west of Cocker Island on the north coast of the NT's. Wasn't to bad as our route back was only 135 miles and we were only becalmed twice for a little over 15 hours.

Worked on the engine eliminating all other possibilities for 1 1/2 days even though I was confident of the problem after the first 2 hours. I could get the engine to run at a high rpm without load by pumping the throttle while cracking injectors during the priming process but as soon as she was idled down she would quit. all the clues were there though as there was insufficient fuel at the injectors at idle position and when I tore the supply fittings off down to the check ball which is meant to hold positive pressure in the injector pump I found tiny filings. Now it is injector pump, injectors and while we are at it we will replace oil cooler as it is mounted on the same side and there was a small coolant leak at the gasket.

Again, your problem sounds like fuel but you need to provide lot's more information before anyone can help you out over the internet.

[BrianGJS]

This may be a long shot but did solve the problem on a Westerbeke generator for a transient visitor to our harbour.
Two things from Westerbeke:
Don't use a 10 micron filter in the racor. We replaced with a 30
If your unit has a somewhat hidden filter under the fuel lift pump check it. This filter on the unit we worked on was almost invisible if you didn't know it was there.