Volvo Penta AQ231B

"HELP!
I have a Volvo Penta A

"HELP!
I have a Volvo Penta AQ231B engine on a 21'6" Renken boat. I dropped it off to the boat yard to have it's annual sea trial done and they said the motor was overheating. I noticed prior to dropping it off to the boat yard that the engine temp did climb to above normal with the water running to the intakes. I replaced the raw water impeller, thermostat and hoses. I ran the engine again this time in a large bucket of cold water and it did the same. I took one end off of the power steering fluid cooler and stuck the garden hose in it. I increased the rpm slightly and the water was sucked into the hose and the engine temperature immediately cooled down. I think that should give me a pretty solid finding that the problem may lay in the outdrive drive and not the engine. The gooseneck hose looks fine between the transom and the lower unit from a visual perspective. I stuck the hose in the other side of the goose neck and flushed the lower unit. I noticed alot of brown and black stuff coming out of the lower unit.
Any ideas or am I chasing my tail.
HELP!!!!!!"

"1) Check the raw water ho

"1) Check the raw water hose connector in the outdrive intermediate housing. If corroded, replace it or the raw water pump will suck air.

2) Have a look inside the grids in the lower gear assembly of the outdrive; or stick a piece of wire through the water drain hole forward of the oil drain plug: you may have a mussel/barnacle farm inside the water passages.

3) Another possibility is that the o-ring at the bottom of the water tube (between the intermediate housing and the lower gear assembly) may be gone.


4) Check the raw water strainer (if you have one installed).

5) It could also be clogged manifolds/risers."

"Thanks El Pescador for the qu

"Thanks El Pescador for the quick reply. If the water was being sucked in the engine by bypassing the outdrive circuit by placing the hose in the oil cooler side, would that kinda eliminate the possibility of the risers being the problem?
Because as soon as I placed that hose in that oil cooler pipe, it sucked the water right in and the engine temp drastically decreased....
Thanks..."

"JP, I read your previous post

"JP, I read your previous post and I am aware of what you say. However, you can never completely discard any other possibility until you have found the real cause of your problem.

Clogged manifolds/risers would cause back pressure and make it difficult for the pump to prime under certain conditions. However, you would have noticed that I mentioned that possibily as the very last one on the short list I provided. The first three possibilities are all in the outdrive, and they are the most likely causes of the problem in my opinion; but if after you check all of them you find that none of them is the cause of your problem, then what? "