Gazza
Member
I'm hoping for some advice on a problem that has just shown itself on our Volvo 2003 28hp raw water cooled engine. It has run well for the three years we have owned the boat, and was running well when she was lifted out for a planned week or so just before the lockdown, so she has been ashore for a couple of months now. When she was lifted back into the water late this afternoon I started the engine as usual only to find no raw water coming from the telltale on the transom. It's very difficult to tell if water is coming out of the exhaust as it is virtually underwater at the very stern. There is good water flow through the inlet sea cock, I've switched the impellor and also confirmed that there is water reaching the impellor pump housing. I've also loosened the engine anode bolt in the block and there seems to be plenty of water pressure there. The anti-syphon valve is showing a good pressure of water when I loosened the top housing.
I haven't run the engine for an extended period to check overheating, although the exhaust temp. sensor seemed to be rising quicker than normal. My immediate thought is that this is probably due to the exhaust elbow being corroded/blocked but I've now had a chance to think about it at home (boat now back on the hard) and I think that the telltale runs from the anti-syphon valve which is immediately after the raw water pump and, therefore, shouldn't be affected by the exhaust elbow.
We haven't had any impellor problems, so it's probably not an impellor blade lodged in the valve.
Unfortunately the boatyard lifting/relaunch schedule is tide dependent and they are apparently working alternate weeks with the yard staff alternating with the engineering staff. With the tides here (Plymouth) this means that unless I get this sorted in the next three days or so, then I'll have to wait at least another week before relaunch.
Am I missing something very obvious? Any help gratefully received ………………….
I haven't run the engine for an extended period to check overheating, although the exhaust temp. sensor seemed to be rising quicker than normal. My immediate thought is that this is probably due to the exhaust elbow being corroded/blocked but I've now had a chance to think about it at home (boat now back on the hard) and I think that the telltale runs from the anti-syphon valve which is immediately after the raw water pump and, therefore, shouldn't be affected by the exhaust elbow.
We haven't had any impellor problems, so it's probably not an impellor blade lodged in the valve.
Unfortunately the boatyard lifting/relaunch schedule is tide dependent and they are apparently working alternate weeks with the yard staff alternating with the engineering staff. With the tides here (Plymouth) this means that unless I get this sorted in the next three days or so, then I'll have to wait at least another week before relaunch.
Am I missing something very obvious? Any help gratefully received ………………….