80’s 9.9 water cooling issue

[Cenextik]

Hey everyone, I’ve got an I believe 80’s 9.9 from my grandpa that was working last season and was winterized. We busted it out now and it starts and will run but on the first test run in the water it stopped spitting water from the telltale after a few minutes. Shortly after it started to lose power then shut off. I’ve tried running heavy mono up the telltale to see if there’s any debris and I haven’t seen any, though it doesn’t go far before a sharp 90 degree turn into the block that the wire can’t turn to go in. Any advice would be appreciated. Thanks!

 

[racerone]

Do a compression test.----Post the actual values you get.-----If good install a new impeller.-----Possible that motor is damaged from the overheating.

 

[kevinj]

Agreed, compression test first to make sure it's not damaged. If compression is low you might get away with just head gaskets. If the engine itself is fine, then an impeller might get you there. These older 9.9 also had a problem with the water tube grommet deforming and restricting water flow. It's #39 on the Exhaust Housing Parts Diagram. The powerhead must be removed to get to this grommet and you'll also need to replace the base gasket.

I used to have a 1979 9.9 and chased water flow issues until I finally was pointed in the direction of this grommet. No matter what, you should replace the water pump if its age is unknown. Just keep this grommet as a possibility if you still have water flow issues after replacing the pump.