Engine seems to start but rolls to a stop

[JustinT]

Originally Posted by GrowleyMonster

Justin, do you have some Marvel Mystery Oil? It is a much loved product for unstucking stuff and getting it going smooth and slick again. A teaspoon down the hole should slick everything up nicely. It won't hurt your engine oil a bit, either. Barring that, a shot of clean new engine oil. You got a lot of the same crud down there that you had in the upper works.

I did put some engine oil in the hole yesterday, hoping it would have seeped in today. I'm aware I probably need something better for unsticking, I'll have a look at the Marvel Mystery Oil. WD40 never quite does it easily. Yes, each time I poke the pushrod in the hole some gunk comes up with it.

[JustinT]

SUCESS! Hi chaps! Thanks for the help again as that did it.

https://youtube.com/shorts/W5gfHEAb4...kKtTpbKwAeWuQV

I'd have had no idea without your help.

[GrowleyMonster]

Originally Posted by JustinT

SUCESS! Hi chaps! Thanks for the help again as that did it.

https://youtube.com/shorts/W5gfHEAb4...kKtTpbKwAeWuQV

I'd have had no idea without your help.

Great! You should be go for a start, in a matter of hours. I will check in on you when I can but I will have limited communications for the next 5 days or so. Good luck!

[JustinT]

Thanks Growley.

Actually, I need to do the rocker clearnace now. However, I'm troubled. All the videos say TDC then adjust the rockers. But, the cam isn't up for all the pushrods for TDC is it?

[GrowleyMonster]

Originally Posted by JustinT

Thanks Growley.

Actually, I need to do the rocker clearnace now. However, I'm troubled. All the videos say TDC then adjust the rockers. But, the cam isn't up for all the pushrods for TDC is it?

Youtube is your friend. Watch as many vids as you can stand. Also remember that even though both pistons on your engine are at TDC at the same time, (I believe, not a lot of hands-on with Bukh 2 cylinders) they are not both on the same stroke.

You don't adjust clearance when the cam is up and the valve is open. You adjust clearance when the cam is down all the way, and the valve is closed.There will be some gap or slack at that point. When the cam is up, the rod is pushing up on its end of the rocker arm, which is pushing the valve down against its spring, out of its seat and into the cylinder. At that point in the cycle, there is no gap to measure. If you follow exactly along with a good video you should be good to go.

[JustinT]

Thanks Growley
So I went to the boat and I've put all back together, but for the rocker oil pipe from the place in Inverness that they are re-fabricating for me.
Here is a video of the valves and pushrods working, all torqued, all gaps done.
https://youtube.com/shorts/fPc05I_sP...BX_gEwYYeENarH
I rotated the engine by hand a couple of times before spinning it briefly as in the video and it all looked good.
Feeling quite nervous to try the big start-up. Going to wait until tomorrow.
Need to block that oil rocker oil pipe, put a bucket of water on the cooling water feed, bleed the fuel system and then: go for the big start-up.

[deblen]

Just had a thot:
It is recommended in many engine manuals to replace the copper washer/seals each time you take a banjo fitting apart.
I've not had a lot of experience with banjos-they are more of a EU thing.
So if you have weeping banjo joints.....
Good luck!! /Len
Bukh-a,Bukh-a.....

[JustinT]

Cheers Len, a good observation. I had a few copper washers crumble too. I keep thinking I should replace some more.

[GrowleyMonster]

See attached pic. This is from DV-10 manual but same as DV-20 except while one of your TWO pistons is on the compression stroke, the other is on the exhaust stroke. At least that is my understanding.

The whole point of this exercise is to have minimal valve lash but enough to allow complete closure at any normal operating temp. This is all about getting the valves to open at the correct point in the cycle, open wide enough for adequate air flow, keep the valve from striking the piston crown, and closing fully at the right time in the cycle.

Remember the cycle. Intake, intake valve opens and cylinder fills with air as piston moves away from the head after reaching TDC, creating suction. That is intake stroke. Then intake valve closes and piston comes back up toward the head to TDC. That is compression stroke. Then fuel is sprayed into compressed air, which is hot from compression, fuel burns, makes expanding combustion gases, and forces the piston down away from the head. That is the power stroke. Then the piston comes back up with th exhaust valve open, and this is the exhaust stroke. At TDC, the valves switch over again and you are back on the intake stroke, and the cycle repeats itself. The timing of the pistons is determined by the crankshaft. The timing of the fuel injection and valves is determined by lobes on the crankshaft which is driven gear to gear, or with a chain or belt, and turns one full revolution for every two full revolutions of the crankshaft. Remember this relationship. One time in the cycle, TDC is where compression turns into the power stroke. Then the next TDC, the exhaust turns into the intake stroke. For each cylinder, there is a TDC position where you can adjust the valves FOR THAT CYLINDER, and then there comes another point where the piston is at TDC but you can NOT adjust the valves for that cylinder, but you can, for the other one.

When everything is set, turn it over by hand with no fuel and check for proper operation of your valves. When you are quite satisfied, adjust your decompression levers as per the manual. Finally, bleed the fuel system and go for start, with seacock closed, and open it once engine is running. Check controls, run engine, monitor temp, look at your exhaust, and honestly you really ought to have done a compression test there, too, but if it feels right when hand starting, then it probably is in the ballpark. Once your engine is at normal operating temperature, your exhaust should be thin and very clear, maybe a slight amount of gray or white-ish smoke, but only a little. I would only run it a few hours and do an oil change, and check valve clearance and compression again. From there you should be able to go 50 hours before the next servicing, which will include an oil and filter change, and at least the first time, a valve clearance check and compression test. After that, 100 hours to the next oil change. If the oil looks good, honey colored with no suspended stuff, no goopy gunk, then 100 or 150 hours between oil changes and check valves and compression annually, when you change zincs, impeller, belts, and any hoses that look old. Keep an engine log.

If there is an air filter, don't forget to clean or change it. Put a drop of oil on all external moving parts. Inventory your spares. Impellers, belts, filters, filters and lots more filters, oil and fuel. A thermostat. You have no starter I gather, but if you have an alternator then a spare is a great idea. Don't forget to check your batteries and nav lights.

Remember that you do have a lot of gukk in the lower works and some day you will want to pull the engine and give it a good going over, possibly even rebuild it if there is any bearing wear which there will be, after running with gunky oil. Don't forget to service your transmission.

Okay I am outta here. Check you in a few days.

[JustinT]

Thanks Growley. Have a good excursion .

[Wotname]

Regarding copper washers for banjo fitting - if they look physically OK, then they only need to be annealed (i.e. made soft again) before refitting.

To anneal (soften), heat washer until they are a dull red colour (or brighter). Dunk in cold water and you are good to go. A stove top gas ring will provide enough heat.

Soft copper washers seal by deforming but they work harden after some use and no longer deform well enough to seal at times. Annealing them makes them soft again and it is easy enough to do.

[JustinT]

Ah, I see. I never knew. Thanks.

[JustinT]

FAIL! Oh dear, back to the original situation. The engine started, raced like crazy and did the "rolling down to a stop". Sort of, back to square one

[skipperpete]

Originally Posted by JustinT

FAIL! Oh dear, back to the original situation. The engine started, raced like crazy and did the "rolling down to a stop". Sort of, back to square one

“Rolling down to a stop” is ok, clanging, rattling or screeching to a stop is not ok, I think you’re still in the game. Did pulling the stop not work? Any chance the throttle lever was set at full rather than idle during this…?

[JustinT]

Originally Posted by skipperpete

“Rolling down to a stop” is ok, clanging, rattling or screeching to a stop is not ok, I think you’re still in the game. Did pulling the stop not work? Any chance the throttle lever was set at full rather than idle during this…?

I just went back again and we are talking a different beast now. Compression levers really have an effect now ie, crank with them in, turn them, "really interested" diesel noises.

The regulator has been messed about with a lot but I rolled it back a bit right at the regulator to check that. Certainly doesn't want to know with the throttle open.

I also wonder if I should loosen off the solenoid? Always suspected it was iffy.