Bukh 20 overheating

[Johnny WAFI]

Hello all

I have a 30 year old Bukh 20 in Sadler 29 which I have owned for 10 years.

I have more than once experienced overheating without the alarm sounding. I am told this is because the seawater cooling takes 2 routes and only one is alarmed.

I am advised that the fly wheel needs to come off regularly and the T piece needs to be cleared. But well qualified marine engineers disagree about whether to just manually clean or to use a descaler such as RYDLYME. My concern with using a chemical is that it may harm in the engine.

Please can you advise me?

(Back in the day Bukh had 2 guys who understood every minor detail but sadly they were replaced by a salesperson who probably believes that suck squeeze bang blow is something to do with the news about Russel Brand!)

Regards

John Rumsey

 

[vyv_cox]

It is possible to remove the seawater inlet into the block without removing the flywheel but you may need to be creative with the Allen key, cutting one down or maybe rounding the end a little. This is definitely the first move. There has been a thread on this in the past week, so worth a look.

Rydlyme works very well but remove the anode and thermostat. There have been many threads on the subject.

Your understanding of the coolant path is not quite correct. When the thermostat is closed water flows through the bypass. When the thermostat reaches its operating temperature it simultaneously opens the flow through the engine and closes off the bypass.

 

[Poignard]

It is possible to remove the seawater inlet into the block without removing the flywheel but you may need to be creative with the Allen key, cutting one down or maybe rounding the end a little. This is definitely the first move. There has been a thread on this in the past week, so worth a look.

Rydlyme works very well but remove the anode and thermostat. There have been many threads on the subject.

Your understanding of the coolant path is not quite correct. When the thermostat is closed water flows through the bypass. When the thermostat reaches its operating temperature it simultaneously opens the flow through the engine and closes off the bypass.

I have shortened the short leg of a ball-ended Allen* key and that makes the job a lot easier.

* By the way, who was Allen?

 

[RivalRedwing]

Vyv is spot on (as always) when you remove the inlet 'poker' do use a bit of rigging wire or similar to ensure no blockages through its full length.

 

[vyv_cox]

* By the way, who was Allen?

I didn't know but Wikepedia does

Allen (brand) - Wikipedia.

 

[Poignard]

Messrs Allen, Stillson, and Fox:

"Their name liveth for evermore".

 

[Johnny WAFI]

It is possible to remove the seawater inlet into the block without removing the flywheel but you may need to be creative with the Allen key, cutting one down or maybe rounding the end a little. This is definitely the first move. There has been a thread on this in the past week, so worth a look.

Rydlyme works very well but remove the anode and thermostat. There have been many threads on the subject.

Your understanding of the coolant path is not quite correct. When the thermostat is closed water flows through the bypass. When the thermostat reaches its operating temperature it simultaneously opens the flow through the engine and closes off the bypass.

Thank you so much.

 

[Johnny WAFI]

Vyv is spot on (as always) when you remove the inlet 'poker' do use a bit of rigging wire or similar to ensure no blockages through its full length.

Thank you so much.

 

[wingcommander]

Don't forget to block off the bypass when flushing. As Viv mentioned remove stat and anode . I then block off the bypass by disconnecting the hose from the poker, cover said poker with a polyethylene bag ,and then carefully refit hose so not to puncture the bag. The flushing route is now from raw water pump ... and exits the hose from stat outlet.. agree poker can be removed with Allans quay without removing the big round heavy thing .

 

[TC Tuckton]

Don't forget to block off the bypass when flushing. As Viv mentioned remove stat and anode . I then block off the bypass by disconnecting the hose from the poker, cover said poker with a polyethylene bag ,and then carefully refit hose so not to puncture the bag. The flushing route is now from raw water pump ... and exits the hose from stat outlet.. agree poker can be removed with Allans quay without removing the big round heavy thing .

Thank you for this idea (plastic bag). It's a simple way to block the bypass and I can imagine how to do it on my MD11C.

 

[Poignard]

I just squeeze the hose from the poker to the thermostat tower.

 

[LittleSister]

Don't forget to block off the bypass when flushing. As Viv mentioned remove stat and anode . I then block off the bypass by disconnecting the hose from the poker, cover said poker with a polyethylene bag ,and then carefully refit hose so not to puncture the bag. The flushing route is now from raw water pump ... and exits the hose from stat outlet.. agree poker can be removed with Allans quay without removing the big round heavy thing .

???? Isn't the poker part of the normal - i.e. hot engine - coolant path through the engine, not part of the - cold engine - bypass?

 

[wingcommander]

???? Isn't the poker part of the normal - i.e. hot engine - coolant path through the engine, not part of the - cold engine - bypass?

The poker is a Y shape . The starboard side branch going to bypass.

 

[RivalRedwing]

I just squeeze the hose from the poker to the thermostat tower.

A brake pipe clamp (not too firmly applied) is very useful for this

 

[Poignard]

A brake pipe clamp (not too firmly applied) is very useful for this

Yes.
That's what I have.
Less risk of damaging the pipe than the Mole grips recommended to me by Al from BUKH (UK) Ltd.

 

[Rhylsailer99]

Hello all

I have a 30 year old Bukh 20 in Sadler 29 which I have owned for 10 years.

I have more than once experienced overheating without the alarm sounding. I am told this is because the seawater cooling takes 2 routes and only one is alarmed.

I am advised that the fly wheel needs to come off regularly and the T piece needs to be cleared. But well qualified marine engineers disagree about whether to just manually clean or to use a descaler such as RYDLYME. My concern with using a chemical is that it may harm in the engine.

Please can you advise me?

(Back in the day Bukh had 2 guys who understood every minor detail but sadly they were replaced by a salesperson who probably believes that suck squeeze bang blow is something to do with the news about Russel Brand!)

Regards

John Rumsey

https://www.amazon.co.uk/Youyijia-S...1699006251&sprefix=socket+set,aps,146&sr=8-49 this will remove the piece behind the flywheel, you don't need to remove the flywheel.

 

[Rhylsailer99]

13mm End Plug Stop Fitting Barbed Irrigation Pipe Soaker Hose Antelco Hozelock | eBay I use these to block the bypass pipe, and good luck removing the 4 screws from the thermostat cap . I had a nightmare with mine a few weeks back, that involved having to hacksaw it off.

 

[rotrax]

Yes.
That's what I have.
Less risk of damaging the pipe than the Mole grips recommended to me by Al from BUKH (UK) Ltd.

I welded two bits of 3/8th round bar to a pair of old mole grips. A very useful clamping tool for all sorts of jobs.