TAMD 71B Overheating

[volvopaul]

Remove the inlet hoses and check there are no blades blocking the inside of the hose.

The old style rubber hoses can delaminate causing narrowing of the hoses restricting flow to the pump.

 

[boatingdave]

Plan B - exactly the same symptoms as you although mine was overheating at a slightly higher revs than you indicate. I still stand by the fact that most likely cause is going to be the raw water inlet, fresh water side is normally easier to test and you would have noticed it with the IR Thermostat gun if the stat wasn't opening. I tested my temperatures with an IR Thermostat whilst tied up at various revs and all showed fine, exactly as you have done. A sea trial was the only place the overheating occurred when the turbos were wound up and the engines were under load (which impacts the back pressure and exaggerates the fault). Simple test, remove the fresh water thermostat from the overheating engine and do a sea trial and if it still overheats then it is highly likely to be the raw water side although I didn't bother doing this because the temperature gun indicated the thermostat was working fine and I was actually pointing the gun at it when the thermostat opened. On my TAMD71B the water flows from the sea strainer via a plastic reinforced hose straight to the pump and then via rigid pipes right through to the outlet of the gear box oil cooler where there is a flexible rubber pipe to the exhaust elbow. There are no rubber pipes to delaminate in my particular installation. It doesn't have to have be much of a drop in flow for it to effect the cooling at high revs/load.
I assume you've taken the tops of the heat exchanger/intercooler off to check the bores look OK (10 minute job). That is one of the few places you are likely to get a scale build up and the heat exchanger (first one after the raw water pump and the the only fully 'wet' exchanger) is the one most likely to catch any debris if the impeller has broken down.
I can only speak as I find, it worked for me, symptoms are spookily similar to mine and a few other posts and one of the simplest to resolve. Jabsco can sell you a replacement pump (new) for less than £500. I can let you know part numbers if you want them (PM me).

 

[SkipK]

I know several years have past but if you get this message Any Jabsco part numbers for replacement parts, rebulid kit, pump would be helpful I know the impeller is part # 836-0001
Thanks
Skip K

Plan B - exactly the same symptoms as you although mine was overheating at a slightly higher revs than you indicate. I still stand by the fact that most likely cause is going to be the raw water inlet, fresh water side is normally easier to test and you would have noticed it with the IR Thermostat gun if the stat wasn't opening. I tested my temperatures with an IR Thermostat whilst tied up at various revs and all showed fine, exactly as you have done. A sea trial was the only place the overheating occurred when the turbos were wound up and the engines were under load (which impacts the back pressure and exaggerates the fault). Simple test, remove the fresh water thermostat from the overheating engine and do a sea trial and if it still overheats then it is highly likely to be the raw water side although I didn't bother doing this because the temperature gun indicated the thermostat was working fine and I was actually pointing the gun at it when the thermostat opened. On my TAMD71B the water flows from the sea strainer via a plastic reinforced hose straight to the pump and then via rigid pipes right through to the outlet of the gear box oil cooler where there is a flexible rubber pipe to the exhaust elbow. There are no rubber pipes to delaminate in my particular installation. It doesn't have to have be much of a drop in flow for it to effect the cooling at high revs/load.
I assume you've taken the tops of the heat exchanger/intercooler off to check the bores look OK (10 minute job). That is one of the few places you are likely to get a scale build up and the heat exchanger (first one after the raw water pump and the the only fully 'wet' exchanger) is the one most likely to catch any debris if the impeller has broken down.
I can only speak as I find, it worked for me, symptoms are spookily similar to mine and a few other posts and one of the simplest to resolve. Jabsco can sell you a replacement pump (new) for less than £500. I can let you know part numbers if you want them (PM me).

 

[boatingdave]

I know several years have past but if you get this message Any Jabsco part numbers for replacement parts, rebulid kit, pump would be helpful I know the impeller is part # 836-0001
Thanks
Skip K

Sorry, can't remember now and it is too long ago to go through records. However, I can remember I had a conversation with Jabsco and they did have a number of pumps listed. There were two which were identical apart from the end plate (one had countersunk screws and the other had bolt heads) with a significant difference in price and they said the rest of the pumpt was identical. I cleaned up the end plate off the old pump and put it on the new pump. The site is quite informative so if you have a picture of the old pump, compare it to the pictures on the site and go from there. I do have all my emails archived on another machine which I don't have access to at the moment but when I do I'll look for the email thread with them to see if I can get the part number.