I recently had a problem with the Volvo engine overheating during hard running on a Bavaria 34. After asking a lot of questions I decided to check the cast iron exhaust bend off the back of the motor where the sea-water first mixes with th exhaust gases as I was advised that they typically coke up. After taking it off, I was surprised to find it was about 90% blocked with solidified carbon. The engine is about 8 years old and has around 1,300 hours on it.
I replaced the casting which obviously freed up the exhaust and cooling water flow. However the engine still overheated and on further checking I discovered a blockage in the siphon breaker on the delivery of the raw-water pump. The spigots off the siphon breaker fitting stepped down in size to allow smaller hoses to be fitted, but in doing so provided a natural trap for any debris coming from the pump. After cleaning out the siphon breaker and removing the unnecessary small spigots the water flow out the exhaust increased 400%.
The engine perfomance has noticibly improved so hopefully this has solved the problem.
I am told that sail boat diesel exhausts have a tendance to coke up, particuarly if they are not regularly run under a reasonable load, or if only run for short durations, so I don't think this is a specific Volvo problem.
This might be useful information for others as it was a revelation to me.
Regards
Bill
I replaced the casting which obviously freed up the exhaust and cooling water flow. However the engine still overheated and on further checking I discovered a blockage in the siphon breaker on the delivery of the raw-water pump. The spigots off the siphon breaker fitting stepped down in size to allow smaller hoses to be fitted, but in doing so provided a natural trap for any debris coming from the pump. After cleaning out the siphon breaker and removing the unnecessary small spigots the water flow out the exhaust increased 400%.
The engine perfomance has noticibly improved so hopefully this has solved the problem.
I am told that sail boat diesel exhausts have a tendance to coke up, particuarly if they are not regularly run under a reasonable load, or if only run for short durations, so I don't think this is a specific Volvo problem.
This might be useful information for others as it was a revelation to me.
Regards
Bill