Engine seems to start but rolls to a stop

[JustinT]

Originally Posted by Wotname

I suggest it is not firing on the cylinder marked in red and it is firing on the one marked in green.

This means the sick cylinder either does not have enough compression to start when cold or is not getting any fuel via the injector.

Given the other information upthread, my best guess is the lack of compression. Perhaps broken rings or piston lands from the run away event you described earlier.

Originally Posted by GrowleyMonster

Well done, and congratulations!

I assumed you had already checked the injectors for spray pattern, etc. An injector is usually a cheap and easy fix, so good thing to check early on. Anyway, glad you found the prob before doing a partial teardown.

Premature jubilation. I went back on high tide with cooling and it ran for 10 mins and then just stopped. Cranking again sounded sick.

I had checked the injectors and spray patten, I can only assume it just hadn't gone back together well
Idk, why didn't I buy a newer boat?

[GrowleyMonster]

Originally Posted by JustinT

Premature jubilation. I went back on high tide with cooling and it ran for 10 mins and then just stopped. Cranking again sounded sick.

I had checked the injectors and spray patten, I can only assume it just hadn't gone back together well
Idk, why didn't I buy a newer boat?

Well, calculatus eliminatus. To find out what the problem is, find out all the things that it's not. You seem to have eliminated piston rings, cylinder wall scoring, etc but something could be amiss with your valves or decompression assembly. Or injector clogged again? Since it ran well, if only for a while, I would guess that the valve and seat are in good shape. So, something to do with the pushrod or rocker. Dead valve return spring?

Try bleeding that injector line again, let it flow a good bit. Then try a new injector or injector tip, as the case may be.

If you know someone familiar with your engine, maybe remove the valve cover and have him watch your valves as you roll the engine over with a breaker bar. Have a set of feeler gauges handy to check clearance.

You fiddled with your decomp lever(s). Could be something there.

It sounds like you have an engine that is essentially healthy, just minor crap to figure out. Can you get your hands on a running outboard, and install a mount for it, for now? A lot of things suck about an outboard, but it will kick the boat around under reasonable conditions and enable you to easily drop or pick up your mooring, or come alongside a dock, whatever. The biggest downside for me, to having an outboard, is when you are bucking a head sea the prop sometimes comes out of the water, and with really big following seas if the engine is mounted nice and low to keep the prop in the water, your engine gets pooped and is useless until you get it dried out. Oh, and keeping gasoline on the boat. I do dislike having gasoline onboard. But temporarily it might be a good match for you until you get the diesel figured out and running good.

[Wotname]

In addition to Growley's good advice, try transposing the injectors and see if the problem follows the injector or not. If not, concentrate on the valve train and decompression lever mechanism on the wonky cylinder.

These engines are fairly bullet proof but like all engines, they need some love every now and then.

[GrowleyMonster]

Originally Posted by Wotname

In addition to Growley's good advice, try transposing the injectors and see if the problem follows the injector or not. If not, concentrate on the valve train and decompression lever mechanism on the wonky cylinder.

These engines are fairly bullet proof but like all engines, they need some love every now and then.

Swapping the injectors. Good one.

[JustinT]

Ah thank you all, great advice. I have thought of an outboard several time too. The stern is rather high on the Seal 28 though.

[JustinT]

I tried it again on high tide and realised I have no water coming out the exhaust. Which way does the impeller spin?

[JustinT]

Well, back to square one. Still trying to fix the engine. Still the same result.

[GrowleyMonster]

Originally Posted by JustinT

Well, back to square one. Still trying to fix the engine. Still the same result.

How do your fuel filters look? Try bleeding your injector lines again, and make sure you are getting good fuel there. My fuel system has a very tiny leak somewhere that allows air into the system, and the fuel pump doesn't suck hard enough to pull fuel very good when that happens, and so I installed an electric booster pump. I run the pump for starting when it doesn't just start right up, then I shut off the booster pump and the engine's fuel pump can keep up a good flow, pulling fuel right through the booster pump, no bypass.

If no fuel at the injectors, maybe weak fuel pump, maybe clogged or cloggish filters, maybe air leaking into the system. You might be able to use an outboard engine squeezy bulb pump to purge and feed the fuel system. Or use a plastic jug as a temporary tank for troubleshooting. Use a squeezy bulb to initialize flow from jug to filters and fuel pump. Don't forget to run your return line into the jug, too. Sometimes the problem is rust or paint flakes blocking the fuel pickup inside the tank. Sometimes a hole is corroded into the pickup tube.

To eliminate engine control cables as a possible cause, operate the throttle locally, right at the engine. If there are any automatic fuel shutoffs that allow run only when there is oil pressure or whatever, temporarily bypass them by plumbing around them. Common culprits are a water temperature switch or an oil pressure switch. These can be wired to prevent the starter being energized, or they can allow a fuel solenoid valve to close, in which case you can spin the engine all day long and never get a start. Don't run the engine with such safety devices deliberately disabled, for long. This is just to diagnose and isolate the problem.

Even procedures that you already tried, should be tried again.

[JustinT]

Thank you. I have fuel coming through the bleed at the fuel filter, I have changed all the filters. The stop solenoid seems to be working but I do keep thinking of removing it to take it out of the suspects. I have fuel squirting at the injector feeds when they are disconnected. It really sounds like the engine is running but letting go of the starter key results in it just stopping. So my assumption is that it just sounds like it is running but isn't.

I was indeed, as you suggest, thinking of the thermostat.

I felt like "I have bled everything, but should probably do it all again" as all help videos seem to suggest that it is worth going over and over the same thing. Thanks for the encouragement to bite the bullet and go over it all again.

i shall keep plugging away. I am also worried that the cooling water is not circulating. I have the pickup in a bucket of water but no water is being pulled in on the start-up attempts.

[GrowleyMonster]

Originally Posted by JustinT

Thank you. I have fuel coming through the bleed at the fuel filter, I have changed all the filters. The stop solenoid seems to be working but I do keep thinking of removing it to take it out of the suspects. I have fuel squirting at the injector feeds when they are disconnected. It really sounds like the engine is running but letting go of the starter key results in it just stopping. So my assumption is that it just sounds like it is running but isn't.

I was indeed, as you suggest, thinking of the thermostat.

I felt like "I have bled everything, but should probably do it all again" as all help videos seem to suggest that it is worth going over and over the same thing. Thanks for the encouragement to bite the bullet and go over it all again.

i shall keep plugging away. I am also worried that the cooling water is not circulating. I have the pickup in a bucket of water but no water is being pulled in on the start-up attempts.

You may need to prime the raw water pump. The pump should be self priming but sometimes... they need a little help. Hope you got a nice new impeller and you put a little bit of grease on it when you put it in.

And let's see... you checked and adjusted your valves, right? Nobody looks forward to doing that the first time, but then once your cherry is broke, you will keep several valve cover gaskets so you can do it at any excuse. It is really kind of a fun operation and a good first go at really getting into the oily internals of your diesel. Be sure and record all measurements before and after so you know if one valve is always going out of spec.

Usually it is said that the definition of insanity is continuing to do the same thing over and over, and expecting always to get a different result. Well, with bleeding your fuel system, that sort of insanity sometimes pays off. And it is an easy job, usually. I keep a spare 5/8" wrench hanging on a nail in the engine space, just to make it more convenient and so if I drop a wrench into my bottomless bermuda triangle bilge from whence important and precious objects never return, I still have at least one more 5/8" with the rest of my tools, and I can still bleed my injectors any time I think I should.

When you try to start, what does your exhaust look like? And you performed a compression check, right? And you are positive that the prop is disengaged, right?

You won't burn up the engine by starting it and running it for a minute or two with no cooling. What you might do, though, is trash your impeller by running it dry. That's why I suggest lightly greasing it whenever you change it.

[JustinT]

Originally Posted by GrowleyMonster

You may need to prime the raw water pump. The pump should be self priming but sometimes... they need a little help. Hope you got a nice new impeller and you put a little bit of grease on it when you put it in.

And let's see... you checked and adjusted your valves, right? Nobody looks forward to doing that the first time, but then once your cherry is broke, you will keep several valve cover gaskets so you can do it at any excuse. It is really kind of a fun operation and a good first go at really getting into the oily internals of your diesel. Be sure and record all measurements before and after so you know if one valve is always going out of spec.

Usually it is said that the definition of insanity is continuing to do the same thing over and over, and expecting always to get a different result. Well, with bleeding your fuel system, that sort of insanity sometimes pays off. And it is an easy job, usually. I keep a spare 5/8" wrench hanging on a nail in the engine space, just to make it more convenient and so if I drop a wrench into my bottomless bermuda triangle bilge from whence important and precious objects never return, I still have at least one more 5/8" with the rest of my tools, and I can still bleed my injectors any time I think I should.

When you try to start, what does your exhaust look like? And you performed a compression check, right? And you are positive that the prop is disengaged, right?

You won't burn up the engine by starting it and running it for a minute or two with no cooling. What you might do, though, is trash your impeller by running it dry. That's why I suggest lightly greasing it whenever you change it.

Yes, there is a new impeller, but I should check it again. The grease is a good idea. Initially I was removing the impeller during the troubleshooting but now the pickup in the bucket of water was where I'm at. I'll look at priming the raw water pump & check it out generally.

I've not looked at the valves, I'll look into looking at them.

When it did once start in the last couple of years there was white smoke but not heavy smoke. The prop is disengaged.

I've not done a compression check as unsure what I'm doing. A chap locally suggested getting the local garage to do it.

Just a note, this engine, since I have had it, has never been good at cold starts.

[JustinT]

I tired it again yesterday, did loads of going over things. Turned it and it really seemed like it was running, let go of starter key and putt putt putt stop.

[JustinT]

I tried again today. Opened up the thermostat, that is a dead thermostat.

[Wotname]

I've re-read all the posts - it seems clear to me that you have one cylinder working properly and one cylinder is not firing.

Last year you managed to get it to run for some minutes but never actually fixed the fault (which could be somewhat intermittent).

Assuming one cylinder is good, then you need to discover why the other cylinder is not firing. It will only be a lack of compression or the lack of fuel for the sick cylinder.

Go back to basics and do the things necessary to determine which it is - fuel or compression. Worst case it might be both!

Fuel is probably the easiest thing to test if you don't have access to a compression tester.

FUEL test - look for the spray pattern differences between the two injectors and lightly spritz diesel into the air intake while cranking (see post #20). Report back .

COMPRESSION test - decompress one cylinder while cranking and then try the other cylinder, is there any change in behaviour. Report back

This is solvable!

[JustinT]

Originally Posted by Wotname

I've re-read all the posts - it seems clear to me that you have one cylinder working properly and one cylinder is not firing.

Last year you managed to get it to run for some minutes but never actually fixed the fault (which could be somewhat intermittent).

Assuming one cylinder is good, then you need to discover why the other cylinder is not firing. It will only be a lack of compression or the lack of fuel for the sick cylinder.

Go back to basics and do the things necessary to determine which it is - fuel or compression. Worst case it might be both!

Fuel is probably the easiest thing to test if you don't have access to a compression tester.

FUEL test - look for the spray pattern differences between the two injectors and lightly spritz diesel into the air intake while cranking (see post #20). Report back .

COMPRESSION test - decompress one cylinder while cranking and then try the other cylinder, is there any change in behaviour. Report back

This is solvable!

Thank you! I was starting to lose track of what to do at all. Thanks for the summary and tips, I'll try those out. I did make the compression independent to try before. I think it is time to swap the injectors and see what happens too.