Bukh 10HP vertical shaft will not start

[GILow]

Hi Cruisers,

On my recent trip to Kangaroo Island, I ran into a couple of friends who recently bought a delightful little 25 foot sailing boat. Not sure of the make, but very tidy and looks like it will be a joy to own.

It came fitted with a Bukh 10HP vertical shaft engine with a sail drive, but I was surprised to see an outboard on the back. It turns out they have been having some problems starting the diesel. It has been to a couple of mechanics, and they get it going, but it stops not long afterwards. Of course they probably should be going back to the mechanics to ask for an explanation but they are not confident enough to do so, and it is made difficult because the mechanics are miles away on the mainland.

Now they are pretty much out of cash to spend on the engine too. Their son has gone through all the motions, and I peered over his shoulder offering useless advice and I could see he has covered the basics.

Engine is cranking over pretty fast, (though compression does not seem all that great, I am not sure what is normal for these engines.). Fuel is getting to the injector body on the head, cracking the line between the pump and the injector body produces pulses of fuel as the engine turns over, not at great pressure but I assume this is ok because it is only fuel pump pressure at that point, not injector pressure.

I could see no evidence of a glow plug for the engine.

There is an electrical device plugged in at the injector body that appears, from looking at online copies of the owners manual, to be a temperature sensor of some sort and therefore not essential to start the engine. I mention this because I checked to see if it was getting power and it was, but it was not passing any current. I assume it is a switch that makes a circuit when it reaches a proscribed temperature.

Anyway, I know nothing about these engines so I thought I would ask for ideas here. I would particularly love to know if there are things that need to be done to start them, and also a description of the expected compression would be interesting, I was just a little unsure that there was adequate compression.

Over to you for advice,

Matt

[bigpuff]

Oh dear the old bukh 10 , over my life time i could write a book on them,some one might have shaved the head (a no no)many cans of engine start,flat batteries,cracked knuckles,the odd swear word and lots of dollars later. The outboard is the better bet.

[GILow]

Aaargh! Don't say that! I told them it was a treasure. I've read so many nice things about them.

[Lepke]

I don't know the engine, but... 3 things are needed to start a diesel. Heat, compression and fuel. Normally the compression causes enough heat for ignition. A certain amount of compression will get by the rings of a cold engine. Even more if turned over too slowly. When too much pressure escapes, temperatures inside the cylinder don't reach temp needed for ignition. Usually glow plugs or a block heater solves the heat problem. When an engine sits for a long time, sometimes the rings contract allowing too much compression to escape. Removing the injector and squirting some oil on the rings will seal them until the engine warms up. It will smoke.
Make sure the injector is injecting fuel. If using ether, too much can break the rings. It temporally raises compression beyond normal. Once the rings are broken, the engine will always need ether until the rings are replaced.

[NCboatrx]

Originally Posted by bigpuff

Oh dear the old bukh 10 , over my life time i could write a book on them,some one might have shaved the head (a no no)many cans of engine start,flat batteries,cracked knuckles,the odd swear word and lots of dollars later. The outboard is the better bet.

Unfortunately the post here is correct. Most likely this engine has low compression and it will be cheaper to replace it than to fix it.

[xsteel]

I have a Bukh 10 shaft drive. It was leaking oil so when passing thru' Sydney I paid for a reconditioned exchange engine. The 'new' one has been great although a few too many slight diesel & oil leaks for the 1st 2 months but to Bukh credit they fixed all under warranty on my way up the east coast. I would suggest to call Graham at Bukh in Sydney & discuss options with him.

[Victory 28]

Almost for a certain there is air in the system, find the leak and bleed the system up to the injectors. You cant stop a Bukh!

[Mike Banks]

Download the workshop manual or sent to the agent for one. That is pretty much an essential if fiddling with engines. I just downloaded the workshop manual so it is available.

It sounds as though there is air in the injector pump--and if the engine spins rapidly there may be a sticking valve--probably the exhaust valve.

Pull off rocker cover and turn engine by hand watching tappets (I am not familiar with the Bukh engine--but with a torch one should see if there is a valve stuck open. If there is sometimes it can be shaken loose with a drift and some gentle tapping on the top of the rocker when it is depressed,

Then having bled the injector pump itself--

Try starting it again.



One thing--there is a decompression lever for hand-starting on some models. Make sure this is no9t caught up on something.

-

[GILow]

Thanks all. By the sound of it there are no subtleties to this engine I might be missing.

They don't have the money to do anything to it, so here's to hoping it is something simple like a compression lever in the wrong position. I'll get them to double check that.

I will also get the. To try the hairdryer trick, that would at least confirm poor compression if the engine starts.

Matt


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