Next Step to Get Diesel Started

[NOLA_sailing]

So last weekend my diesel (Universal M3-20b) would crank but not start. When purchased two months ago it had dirty fuel. Prior to being delivered, the tank was cleaned and both filters were replaced. Engine had been run about 30 hours since then. Last time it ran I did notice it was a little rough at idle so I am thinking it's a fuel issue. I changed both fuel filters; old filters seemed relatively clean. Lift pump is working as the filters fill with fuel when I try to start and can still hear it after. My last thought is to bleed the injectors even though the system is self-bleeding. If this fails to get her running, what step is next? Thanks for any insight.


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[ShaktisBoy]

check the fuel lines themselves. Recently we had 1 collapse enternaly. There is a inner plastic like liner in some fuel hose that can starve the engines fuel suuply. Also double check that your system is indeed airtight. I have seen bubbles in my racor and ended up changing out the fuel line between it and the lift pump. Be carefull crankning too much without the engine running as you can introduce water into your exaust system if you have a waterlift muffler installed. There is usualy a drain of some sort on a waterlift muffler to keep water from getting back to the engine. You didnt say how many hours are on the engine and weather or not you know you have good compression.

[NOLA_sailing]

Thank you! I do not know the hours off hand but will make note next time I am out there. Other than the bad fuel, the diesel has run very smoothly.


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[SkiprJohn]

As Shaktis says: Be very careful about cranking the engine too much while water is being pumped into the system. If it doesn't catch quickly and start running you'll be pumping water into your exhaust manifold. Turn off the valve to your saltwater inlet to your engine until it fires. Shut your engine off immediately then open the valve and start your engine again.
Try bleeding the injectors. Clear fuel without bubbles is needed. Make certain your fuel filters are seated properly and not letting air into the system. If there is a question about hoses in your system then by-pass those and use fuel from a clean can of gas. Just disconnect the hose to your engine filter and splice in a hose from an outboard tank with a pressure bulb on it. If the engine runs fine with that tank but won't with your original plumbing then you know there is something wrong between your engine and your tank somewhere.
Good luck!

[Cheechako]

and beware that I think we sorted out on this forum that small bubbles in your Racor filter is normal.... I'd probably try bleeding the injectors. Also possible that an injector needs rebuilt....

[Old Snipe]

Probably wouldn't hurt to have the injectors/nozzles tested as well.....if you know they might have had dirty fuel run through before you bought the engine.

[NOLA_sailing]

Thank y'all very much for the input. I bled all three injectors with no improvement. I opened what I am assuming is the air intake and found what was left of a filter. Is it possible that the engine sucked a piece of the filter and it's clogged somewhere inside the block? Please see picture.


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[SkiprJohn]

How familiar are you with bleeding the injectors? Did you get any one of the cylinders to fire? Did you get a clear stream of fuel at each? Do you have a fully charged battery and is the engine spinning fast enough to fire? Are there glow plugs on your engine or a pre-heater?
I know these are all kind of rudimentery questions but we get folks from very experienced to knowing nothing so we just have to start from the scratch in finding out what your experience is.

[NOLA_sailing]

I have very basic, self-researched skills. Fortunately, I have a slip neighbor taking a look who thinks it may be an issue with the glow plugs. I'll keep y'all posted. Thank you again.


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[a64pilot]

That air filter screams that the engine hasn't been serviced, you need to assume all replaceable items are over due, like the raw water impeller for instance.
I doubt the filter going through the engine caused much harm, not enough to kill it anyway

[PatH]

I would also suggest pulling the injectors and having them cleaned and Pop tested. I assume by your username you're in NOLA?
I'm over in Biloxi and use a place in Mobile to do all my injector and injection pump work. Test Calibrations, hit me up if you need the info.
As others have said make sure you are getting a good stream of fuel from the injectors and are using the proper bleed down sequence. I know the Perkins 4-108 needs the injection pump bled as well, not sure on the Universal.
If you had terrible fuel, and an air filter like that one, I'd go ahead and change the fuel lines, if a small crack or loose fitting can allow air in.
Good luck.


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[NOLA_sailing]

Thank you everybody. This particular issues does seem to be clogged injectors and I am going to pull them next time I'm out there. I agree that all serviceable items need to be replaced and am working down that list.

Pat I am in New Orleans and bought the boat in Mobile from Turner Marine. Brought it to Nola last month. Depending on who I can find around here, I'll let you know if I need the info for Test Calibrations.


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[PatH]

Something to think about is if 'gunk' etc made it to the injectors, it also went through the high pressure injection pump. Not saying it's your problem, but to keep in mind. Test Calibrations has also done pumps for me relatively inexpensive compared to a new pump.


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[a64pilot]

I've never seen clogged injectors, dirty, filthy ones with poor spray patterns that caused an engine to knock like it had a bad rod bearing, yes, but not clogged.
If they in fact have trash in them, the pump needs to come out and be cleaned before it gets too damaged, pump is a complicated little bugger, it's essentially a tiny engine with pistons, valves etc one for each cylinder, if it got dirt in it, I can't see the dirt just moving through, I bet there is some still in the pump causing wear.

[DeepFrz]

Set up a small fuel supply that is gravity fed so that you can bypass all fuel lines and filters to see if you can start to narrow down the problem.