Boatymcboatface123
New member
Hi all,
I'm looking for some experienced advice or tips.
I have just recently taken on a job diagnosing an old AQAD40B that is overheating.
The owners bought the boat last year, It started overheating couple of months after.
The engine has no hour meter or maintenance history.
They had a mechanic who:
1: replaced thermostats
2: clean heat exchanger
3: replace end caps (heat exchanger)
Now I took over (unfortunately) and I have checked:
4: exhaust mixer elbow, removed it wasn't blocked, ran water through to check
5: sea strainer
6: G/B cooler
7: raw water pump and impeller
8: replaced drive belts (jcw pump pulley slipping)
9: ran the engine with raw water discharge hose removed to assess flow, seemed quite sufficient, flow increased with rpm.
I used a temp gun on sea trial, all temps on raw water circuit 25-30'c, jacket water gets up to operating temp and keeps climbing to 90'c+
I haven't checked the oil cooler or aftercooler yet as there is more work involved and the raw water temp and flow seemed satisfactory??
The jcw pump pulley spun quite freely when belts removed, didn't look like it was leaking from teltale, but how would I know if jcw pump is causing it to overheat?
Any advice or tips would be much appreciated.
Cheers!
I'm looking for some experienced advice or tips.
I have just recently taken on a job diagnosing an old AQAD40B that is overheating.
The owners bought the boat last year, It started overheating couple of months after.
The engine has no hour meter or maintenance history.
They had a mechanic who:
1: replaced thermostats
2: clean heat exchanger
3: replace end caps (heat exchanger)
Now I took over (unfortunately) and I have checked:
4: exhaust mixer elbow, removed it wasn't blocked, ran water through to check
5: sea strainer
6: G/B cooler
7: raw water pump and impeller
8: replaced drive belts (jcw pump pulley slipping)
9: ran the engine with raw water discharge hose removed to assess flow, seemed quite sufficient, flow increased with rpm.
I used a temp gun on sea trial, all temps on raw water circuit 25-30'c, jacket water gets up to operating temp and keeps climbing to 90'c+
I haven't checked the oil cooler or aftercooler yet as there is more work involved and the raw water temp and flow seemed satisfactory??
The jcw pump pulley spun quite freely when belts removed, didn't look like it was leaking from teltale, but how would I know if jcw pump is causing it to overheat?
Any advice or tips would be much appreciated.
Cheers!