Challenge: Seized Bukh - Mechanics Puzzle?

[Wotname]

Maybe not a challenge in a traditonal sense but this happened to me about 15 years ago and I only found out the real cause accidentally some 2 years later.

See if you can guess (or work out?) what really happened?

Thee boat was a 28 ft carvel Wanderer built in NZ in the fifties. It was fitted a single clyinder raw water cooled Bukh diesel.

The motor wasn't running at the pre-purchase inspection and trial sail but was sorted out by the PO before the survey was completed. He stated the battery had been flat and a new mixing elbow was fitted.

It ran OK for me for a couple of weeks. Then the boat was trucked across Australia (about a week on the road) and moored in Perth without being used for 3 months over winter.

Next time I went to start it, it appeared to be completely seized and I could not turn it over manually. Just wouldn't budge an inch.

Called the diesel fitter at the mariner and he sorted it out during the week.

He reported that he really didn't know what was wrong but had fixed the engine by just rocking the flywheel back and forth until there was some slight movement. He continued in the same way until it was rotating 10 or so degrees in each direction until with a bit more force and a small bang, everything worked again. He then started the engine without a problem and it ran OK. Charged me an for an hour and I was left a bit mystified. Still it ran OK that summer.

Next summer, it still ran OK but occasionally the water pump would stop pumping intermittently without apparent reason but would work again after pulling out the impellor, looking at it and then refitting it.

What had seized the motor?

[David M]

Which pump? The raw water or coolant pump? Was the initial seizure from internal corrosion or the pump?

[Wotname]

Originally Posted by Wotname

....... It was fitted a single clyinder raw water cooled Bukh diesel. ........

Originally Posted by David M

Which pump? The raw water or coolant pump?

I should have made myself clearer .
There was only one pump, the raw water cooling pump.

Originally Posted by Wotname

What had seized the motor?

Originally Posted by David M

Was the initial seizure from internal corrosion or the pump?

That's what I want you to tell me but you are certainly on the right track. Seems it took you only a couple of minutes, it took me () a couple of years.

[David M]

No idea....any more clues?

[Wotname]

"Gear driven raw water cooling pump" any help

[David M]

Something got in the pump?...like a broken off lobe that got in the outlet? Or a seized pump bearing? Something got in the gears?

[Chief Engineer]

I want to hear the answer puh-leeze...I just inherited a seized Bukh

[Wotname]

Originally Posted by David M

.... Or a seized pump bearing? ....

Yup, found it after getting tired on the intermittant nature of the water pump so I pulled off the motor. I thought it was strange that it had a roller bearing at one end and a bush on the other.

Turns out the "bush" was a completely rusted up roller bearing. All the rollers were rusted together and I assume they had rusted to the shaft going by the wear marks on the shaft.

Being a gear driven pump, when the pump seized, the motor appeared to be seized. The force applied by the diesel fitter broke the rusted mating surface of the shaft to the bearing and all seemed good. The shaft just ran against the rusted up roller bearing for the next year or so !!

I replaced the pump completely and no more problems in the department.

I guess your problem won't be so simple Chief; but I hope it is

[Chief Engineer]

Domini Domini Domini

Originally Posted by Wotname

Yup, found it after getting tired on the intermittant nature of the water pump so I pulled off the motor. I thought it was strange that it had a roller bearing at one end and a bush on the other.

Turns out the "bush" was a completely rusted up roller bearing. All the rollers were rusted together and I assume they had rusted to the shaft going by the wear marks on the shaft.

Being a gear driven pump, when the pump seized, the motor appeared to be seized. The force applied by the diesel fitter broke the rusted mating surface of the shaft to the bearing and all seemed good. The shaft just ran against the rusted up roller bearing for the next year or so !!

I replaced the pump completely and no more problems in the department.

I guess your problem won't be so simple Chief; but I hope it is

[Brent Swain]

A friend with a single cylindre Buhk priced out a thermostat. Finning wanted $55. He bought an outboard thermostat for $7 made up a washer for an adaptor and it has run happily ever since.

[Wotname]

Originally Posted by Chief Engineer

Domini Domini Domini

Chief, are you kidding me or are you seriously saying that the seized Bukh you inherited has the SAME fault??????????

[Chief Engineer]

Well...I went to the Bukh today....took off the water pump and the housing that covers the chain. Trying to move the flywheel din't move anything.

Before I get too involved in this....are headgaskets/injector/valve springs still available? From where? (I'm in Baltimore.)

[Wotname]

Sorry, I can't help with info on parts, especially from Oz and I sold the yacht and Bukh some 12 years back - now have a Yanmar 2GM20

[Morgan Paul]

Before I get too involved in this....are headgaskets/injector/valve springs still available? From where? (I'm in Baltimore.)

This might help Chief :

http://www.marineengine.com/discus/m...04/22093.shtml

[Clive]

Originally Posted by Brent Swain

A friend with a single cylindre Buhk priced out a thermostat. Finning wanted $55. He bought an outboard thermostat for $7 made up a washer for an adaptor and it has run happily ever since.

Following this old post I was wondering if you could find more details Brent ie type of thermostat and talk through of mod. I'm over cost of Bukh parts and saving for a Kubota based engine.