1983 Bukh 20 hp. Indirect injection

[vyv_cox]

A rather weak point on the Bukh is the water pump seals. Older engines only had a very small drilling between the seals and the drive. This is easily blocked, which then can allow water that passes the seals to enter the crankcase. Later pumps have a much larger opening. More info on my website.

 

[James_Calvert]

are there any symptoms of impending elbow failure?

They are a nice silvery colour all over when new. They might show some uneven discolouration with age, time to source a spare, but it might survive another season or two. Any hint of a crack and its failure is imminent, and it should be replaced. I guess at this stage some exhaust bandage would hold it together for a bit longer, if you spotted it.

Over the 33 years we've looked after our Bukh, the elbows have lasted at least 6 years each time.

 

[Champagne Murphy]

A rather weak point on the Bukh is the water pump seals. Older engines only had a very small drilling between the seals and the drive. This is easily blocked, which then can allow water that passes the seals to enter the crankcase. Later pumps have a much larger opening. More info on my website.

Thanks Vyv, mine failed a couple of years ago and was replaced. I appreciate your point about cleaning the drain hole, but is it possible to enlarge the hole without ill effects?

 

[chewi]

Did mine last year but there were no warning signs. Wasn’t a big job at all but heat was required to separate the elbow from the ‘base’ to which it was threaded.

Stainless ones can be had on ebay for about £140, or they had them in stock at Elkins Yard (Christchurch Dorset) that bolt to the cylinder head, so no need to unscrew from the flange.

 

[awol]

Can be hand started. A big PLUS in my mind!

 

[sgr143]

Check the engine shut off solenoid works - when the engine is working, turn the key to 10 o'clock and hold it there. Engine should stop and then when fully stopped you return key back to 12 o'clock

Mine burnt out, due to the key being worn and not springing back from the "stop" position like it ought to. Result, on coming back from a trip with two friends who were new to the boat, was an engine that wouldn't stop. Oh how we all laughed. Well, they did, anyway.

A towel wrapped in a plastic bag held firmly over the air intake eventually persuaded the mighty Bukh to stop.

New stop solenoid (pricey); and a "press to connect" button (cheap) in the wire from the ignition switch to the solenoid. So now "engine off" means "switch anticlockwise, push the button till the engine stops".

So Dylan, if there's any doubt about the switch (after 35 years in use, there might be) fit the "off" button before you end up with a fried solenoid.

Steve

 

[seumask]

Echo that. I put some store by the fact t hat I can get it going without the electric's available. I start mine ( DV24) by hand 2 or 3 times a year. Admittedly it requires some effort with the crank handle and the decompression lever activated while you get the heavy flywheel up to speed then release the decompression lever. Usually goes first or second time.

 

[vyv_cox]

Thanks Vyv, mine failed a couple of years ago and was replaced. I appreciate your point about cleaning the drain hole, but is it possible to enlarge the hole without ill effects?

I think that would be a good idea. Need to get the shaft out first and clean up well but then all good.

 

[Gitane]

Echo that. I put some store by the fact t hat I can get it going without the electric's available. I start mine ( DV24) by hand 2 or 3 times a year. Admittedly it requires some effort with the crank handle and the decompression lever activated while you get the heavy flywheel up to speed then release the decompression lever. Usually goes first or second time.

Agreed, it can be hand cranked and I have done this a few times. When the weather is warm, hand cranking is OK and she starts after a couple of goes, however, in the depth of winter when the lub oil is really thick, I found it impossible to hand start.


Below a link to a clip on how I hand start my DV24 with a tip on how to decompress the engine.

https://www.youtube.com/watch?v=IjueyfWDSeQ

 

[seumask]

I have managed to start mine at 5 centigrade this winter while ashore. I'll grant you some effort was involved but it started after a few goes and I suspect the DV verison is easier with its higher pressure injection system, than the original 20, Mines from 1998 so a bit newer!. Here's a link to what its like to hand start it , the key is to get up to speed in your own time, use the weight of the flywheel to go through 1 or 2 compression for start, not your own muscle power as that wont work.

https://www.youtube.com/watch?v=IjueyfWDSeQ

I understand that you can get an old style pull stop for these engines if you are worried about the Solenoid stop.
I'm not sure why you'd block the air inlet to stop it. I have managed to stop mine by running by operating the decompression lever. Simples!

 

[VicS]

I have managed to start mine at 5 centigrade this winter while ashore. I'll grant you some effort was involved but it started after a few goes and I suspect the DV verison is easier with its higher pressure injection system, than the origional 20, Mines from 1998 so a bit newer!.
You can get an old style pull stop for these engines if you are worried about the Solenoid stop
I'm not sure why you'd block the air inlet to stop it. I have managed to stop mine by running by operating the decompression lever. Simples!

Generally not recommended to stop an engine with the decompressors. Dont know why, not designed to be used that way I guess

 

[neilf39]

My Bukh 20 dated from 1980 and was still going strong when I replaced it. Very easy to maintain. I think it was a bit down on power but not surprising for a 38 year old engine. Replaced it with a Beta 25 as I found it a bit noisy and vibrated a fair bit and on a 15 to 18 hour motor got a bit wearing. I could hand start it with the handle (although it half kills you). I have stopped it with the decompressors a few times with no apparent damage as the wire to the stop solenoid used to fall off regularly until I fixed it. It always steamed a bit but as have I used it to go to North Brittany and the CIs over a few years and run it for 15 hours at a time it does not seem to be a problem. They are heavy compared to modern engines but I think that is why they last forever.

 

[garvellachs]

I think the don't stop with the decompressor thing is about not continuing to inject unburnt fuel into the cylinders - there's a risk of enough accumulating to lock the engine?

 

[VicS]

I think the don't stop with the decompressor thing is about not continuing to inject unburnt fuel into the cylinders - there's a risk of enough accumulating to lock the engine?

Its not going to accumulate with the exhaust valves held open !

 

[alan_d]

Just another report of experience with the Bukh (DV20) exhaust elbow. It looked pretty new when I bought the boat, but after seven years (approx 350 engine hours) it was looking discoloured and seemed to have a small crack, so I replaced over the winter.

 

[dylanwinter]

It has a stainless steel elbow - which I assume is a good thing.



this is it starting from cold....

https://www.youtube.com/watch?v=bXWdIsaO1sk

when below 5 degrees C it needs heat from a blow torch blowing into the air intake - which I assume is not a good thing


The three year old Wallas heater runs on paraffin - is that a good thing?

 

[VicS]

Being to look like a pile of trouble.........

I'd not want an engine that used a thermostart let alone one that needs a blow torch to start it


Bit of a pain if the heater needs paraffin rather than running on diesel, but I guess you will stick to candles in flower pots anyway.

 

[neilf39]

Mine never needed heating to start even below zero. Took maybe 5 to 10 seconds turning over. It was 38 years old.

 

[vyv_cox]

I think the don't stop with the decompressor thing is about not continuing to inject unburnt fuel into the cylinders - there's a risk of enough accumulating to lock the engine?

Just a guess but I suppose that with the exhaust valves held down there is a massive clearance between cam followers, push rods and tappets. It would seem possible that damage or displacement might result.

 

[LittleSister]

Just a guess but I suppose that with the exhaust valves held down there is a massive clearance between cam followers, push rods and tappets. It would seem possible that damage or displacement might result.

Seems most unlikely, otherwise (a) why would Bukh fit such a device in the first place, and (b) why have I never heard of anyone suffering such an outcome, given the number of Bukhs there have been out there for many decades?

I spent years using the decompressor to stop my old magneto ignition pushrod 500cc single AJS without ill effect.