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AD41B Temp Problem

oahufish

New member
"My port eninge, an AD41B star

"My port eninge, an AD41B started running 10 degrees hotter than my starboard engine last spring. It run's 190-200degree's at trolling speed and 205-210 at full rpm. I have changed impeller several times,rebuilt seawater pump, swapped seawater pump with other engine, taken off exchanger, oil cooler, transmission cooler,exhaust elbow and aftercooler insert and cleaned them, all have great water flow. Also replaced thermostat, temp sensor, swapped around temp gauges on my panel and replaced belts and all hoses from seacock to seawater pump. After all this, it seems to have great water flow but still continues to run 10degrees hotter than Starboard engine. I've also noticed temp will fluctuate more than starboard engine, it will waiver between 190-200 at same rpm."
 
"Verify all temps with IR gun

"Verify all temps with IR gun before going forward. Corrosion in wiring can make incorrect temp gauge reading, and make it appear that port engine IS running hotter, when in fact its the wire from the sensor thats messed up. (On my boat when I turn on dash instrument backilight, temp goes up 10F instantly....temp reading back to normal with backlight turned off)

Afterwards, follow these steps:

First try swapping H/E radiator caps. Then verify that there is no gunk in the coolant line connecting H/E overflow canister and turbo exhaust housing. Then verify that H/E end cap is not extending back towards Aftercooler under power.

Post findings, good luck"
 
"Caps have a rating of 3 PSI,

"Caps have a rating of 3 PSI, not sure if that will influence the temp as much as a air lock.
You say you have good flow, IF so that rules out suction colapse and suction air leak on the outdrive. BUT if you are not sure about this assumption then check condition of hoses clamps and if you have the valve on the trans shield.. that it is not clogged and is fully open. When all this is double checked on the raw side then I would look at the banjo and vent hose on the tank and turbo to ensure they are clean and some fluid is escaping when removed or when engine is running.
I do not understand Stringers advice on the H/E end cap, and since I own a pair of these beasts, I don't want to miss out on any advice."
 
"I've already swapped caps

"I've already swapped caps on the H/E overflow tanks, and it did not seem to make a difference.Not quite sure what you are talking about when refering to the "Banjo". Is that the vent hose that is located right next to the H/E cap? I don't seem to be losing any fluid, at what point is it supposed to overflow? Haven't checked the line between the turbo and overflow tank yet. Should that be a continuous flow between tank and turbo while the engine is running? Is that freshwater/coolant that flows to turbo and if so, where does it return back to H/E Tank? I don't remember seeing a return line. I'll look around and see if I can find an IR gun.
Mahalo
Lee"
 
The banjo is the round thingy

The banjo is the round thingy with a hle that a bolt runs thr the middle. It has a sealing washerboth sides. Make sure the hose is clear and bolt's hole is not clogged. Air is supposed to bleed back to the tank. depending on how much incline of the vessel will determine if fluid flows.
 
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