Bukh 20 overheating

[JamesDavis]

Have thoroughly cleaned the raw water injector and the exhaust manifold with limited success as it still overheats after about 20 mins. Nice man from Bukh said it sounds like a head off job to clean the coolant channels. Has anyone else had similar problems and managed to cure it without taking thr head off or could I be persuing the wrong problem? On a positive note it has been quite fun having to sail to get anywhere but it does make for some hairy moments when getting in and out of Portsmouth Harbour.

 

[VMALLOWS]

Are you quite sure that it is overheating, not just the indication on the gauge?? (notoriosly unreliable). What is the water flow like from the exhaust? .... its not that much from the BUKH .... about one spurt every 5 seconds at idle with a waterlock..... a light spray at normal revs. Is the engine itself getting significantly hot? .... mine is only ever 'hot' to touch .... never unbearable .

If the flow is insuficient, double check all possible causes of obstruction (bits of broken impeller stuck in pipes ...... weed in intake pipe..... before the expensive options!

 

[philip_stevens]

Also, it is very normal for a Bukh 20 to steam. Don't take this as overheating.

If you can, put your hand into the exhaust outlet water flow. It should be about 65degrees or so. It WILL be hot to the hand, but not overly so. So be very wary and careful when doing so, in case the engine is overheating.

regards,
Philip

 

[Guest]

have you looked at the thermostat?

 

[Guest]

Agree with all that everyone else says. Do check that you haven’t installed the thermostat housing around the wrong way. I did once, result was that once the engine warmed up, flow to the block was cut off. Not very good.

However, many years ago, as a result of the cooling ways becoming clogged with lime scale, had to clean them out. The symptom was that the back of the head was poorly cooled, whereas the front was OK. This set up stresses in the block and head such that one dramatic day a core plug popped out. Being in Corsica we removed the head, saving the gaskets etc, and were able to put it back. When head was off, however, could see that cooling ways were badly clogged up. So next trip, took out new head gasket set (very expensive) some obvious spares and my somewhat experienced and skilled brother. We found that the only way to clean out the cooling ways was to take the head off, and chip out the lime scale with sharp implements, then finish off with a solution of hydrochloric acid. This took my brother, myself and 3 female crew 2 days. We were also helped by just about every inquisitive passer by.

However, it is worth it. The engine was fine for many years, managing with the Canal du Midi and a constant motor from Roscoff to Weymouth as a result of a tight deadline and no wind.

 

[JamesDavis]

Re:Many thanks for your replies.Happy Christmas .

Re:Many thanks for your replies.Happy Christmas .