Mercruiser 350 horizon raw water pump.

Weber

I test ran my motors on the muffs and notice two issues with my port motor.

My motors have the air activated drain down system that I use for winterizing.

When I ran the port engine I noticed water lightly spraying out of the orange drain down port on the starboard side.  I also notice water pouring out under the pump.  Closer inspection shows that it is coming from not the pump but the distribution housing were the two blue plugs are.  It looks like it's coming out of the bottom where the water drains out when you fill it with air pressure.

Both engines look the same, but only one is leaking.  I don't see any kind of plug that may have popped out or anything.

Any ideas?

Dream_Inn

If it is leaking out of the pump underneath, then the air activated drain in it didn't seal up.  You can try using the hand pump for the air activation and then use the relief valve again.  Then again, the relief valve may not have ever been pulled to let the air out completely the first time, so it sat all winter with it open.

Also make sure those air hoses are completely in.  To do that, you will need to push in the ring around those hoses and at the same time push the hose in (yeah, kind of a pain).

diggin2day1

My lower water distribution housing is leaking too... Mine is leaking from around the blue drain plug. 

pearson57842

Look closely at the water distribution housing where the plug screws in .  Mine had a hairline crack.  Probably from over tightening plug.  Had to replace housing.

Weber

I'm hoping there is just air in there and I just need to bleed it out, to get it to close.

I thought about that after I left the boat pi$$ed off thinking I need to replace the whole assembly.

Plan to go down this evening to try it again.

Weber

Went down and hooked the hose up, everything is fine.

reneechris14

Good for you

Liberty44140

Reviving this as I have a similar finding. In October I drained both of my 350's using the hand air pump, all went well, lots of water came out of both the water pump and the orange nozzle (both sides of each engine). Used the pressure relief valve to release air and then pulled all 4 blue plugs and hit starter real quick to make sure all water was out. Then ran 4 gal of anti freeze through each side through muffs. Was nice and pink. Left pink in for winter. Anyway went to the boat sat and it looks like some pink stuff dripped out of both orange nozzles and the water pump on one side. My guess is that around a pint per side has leaked (does not look like its still leaking). It has not frozen where by boat is indoors (was 50 F in there this weekend and 25 F outside). So my guess is that since this was likely the first time the air actuated system has been used in at least 5 years it probably didn't close all the way when I released presure and I need to re pressurize and re "release" this spring? I'll check the tubes but I made sure to pay close attention to them when I winterized Any other thoughts? Thanks! 

Dream_Inn

@liberty44140 yes, I'm pretty sure it just didn't release all the way inside the pump.  I had this happen to friend's last spring and it leaked for a bit in early spring.  Fortunately he was able to get it to reseal after messing with it for a bit.  I use mine every year and it seems to seal just fine, so just keep using it!

Liberty44140

Great, thanks John!