Originally Posted by TYPHOON

s/n 2a042709

Originally Posted by lightspeed

Randy did u check the fitting thats in the gimbel that the hoses hook to... Bravo fever ??? that closes up over time and restricts flow

Originally Posted by BUP

possible poppet valve issue

Sensor ground and or harness issue ???

does the psi reading ever change --- Also What is water pressure psi with just key on engine not running ( KOEO ) and at idle and so on for rpms ? if the engine goes into guardian mode what fault codes pull up ? What is water pressure psi readings when it goes into guardian mode ?

These are a CAT engine and the cooling set up and exhaust is not that same standard set up.

ENGINE SERIAL NUMBER -- you can text it to me. Also there is possible PCM updates most likely for this engine if it has not gone back to a Merc dealer. There is many very long Service bulletins for the earlier 8.2 CAT engines. heck one is 30 pages long.

With that said engine serial number is a must and this will determine water flow / parts diagrams

2 of the best tests you can do is clear water hose testing in sections of the cooling system especially from inner transom and forward from there. Also water output tests after the sea pump outlet. Do not run long because of the cats in the exhaust. 15 seconds MAX to compare water flow output one engine vs the other.

Sea pump GEN VII internally scared not pulling enough water -- I WOULD DOUBLE CHECK THAT first and foremost and water output testing can help determine that as well