1986 V/P 225d 280 Overheat

[Soupy73]

This is my first input to this forum. I'm sure my problem had been discussed many times, but I can't find my exact problem discussed. Recently, my temperature started rising towards 175, so I decided to change out the impeller. No change. I took off my risers, which really looked in bad shape, so I replaced them with new ones and new gaskets. I looked into the manifolds ports when the risers were off and there was some small amount of blockage that I cleaned out. The passages seemed o.k. Ran the engine again. No change. Since my circulating pump was original, I replaced it along with a new thermostat. Still no change. I back flushed from the raw water pump to the outdrive. Water ran freely. I forward flushed through the thermostat housing and water is running through the system and into the manifolds. However, I see no water coming out of the two nipples that come out of the sterndrive. Should there be water there? Do you think I need new manifolds? Could use a little help on this one.

 

[Scott Danforth]

pull the drive, replace the water inlet manifold. it is most likely corroded and leaking, causing lack of ability for pump to draw water. it is a common problem that you would find when you replace your bellows every 2 years.

because you dont see water exiting the idle relief ports, you most likely toasted your new impeller from lack of water.

 

[kenny nunez]

Another possible place is this ?O? ring that is at the top of the lower gearcase where it joins to the mid section. This is where the drive pivots for steering, it causes an air leak into the water intake when the boat is on plane. Volvo published a service bulletin on this many years ago.
It is not easy but the manifold that has the nipple where the hose connects can be replaced without removing the drive.

 

[Scott Danforth]

The o-ring is part of the water inlet casting kit