Water pump problem...
 

I'm trying to winterize my stbd engine and not getting very far. I originally hooked up the muffs and fired it up and found a few minutes later that I had no water coming out the exhaust. Pulled the pump and the impeller (GRW) looked fine. Reinstalled and ran water straight into the hose from the transom and it pumped fine. Then I went to winterize again and it wasn't pulling water from the muffs, so I pushed the muffs together to seal better and I could feel the pressure release and it started pulling water. After a few minutes to get the temp up so the thermostat would open, I switched from the hose to the AF mix in a container set up for gravity feeding it down to the outdrive. At that point no af was flowing out and water stopped coming from the exhaust. A friend said that the impeller might be too weak to prime from the drive, so I replaced it today. That is a 1 1/2 hour job because of my engine access. Long story short, and I know it's a little late for that, the M#$%@F@#$&er still isn't pulling water. The other engine took 15 minutes to winterize and now I'm about ready to set the thing on fire. Any suggestions??

I got tired of the muffs a long time ago. I remove the hose from the transom assembly (inside) and pull it up enough so I can get a funnel attached to it and pour the AF in while cranking or idling. It helps to have a friend helping.

Water pump prime
 

Bill
This is a mystery to a lot of us Mercruiser mechanics. It happens every once in a while, we get together at Merc service school and talk about it and it frustrates us all! The one thing that should be checked very carefully is the gasket between the nipple and the transom assy inside the boat where the hose attaches (the hose between the transom and water pump). It could be sucking air.
You're not the only one with this mysterious problem, it is extremely frustrating!
Good Luck
Dennis Moore
FAMILY AND PERFORMANCE BOATING MAGAZINE

I had about the same thing this spring happen.
I was using the muffs from MERC,(rod goes thru the drive intake holes and holds both muffs together) and burned up a brand new, 0 hr impellor. Thought maybe I had a plugged line, so I pulled the drive off. With the drive on a stand and using the Merc muffs, water wouldn't even flow thru the drive itself. I had to force like hell the cups together to get water to flow up the 10" of unrestricted water path! Craziest thing I ever seen. So for chits & grins, I installed my old cheap West Marine generic brand muffs, water flowed thru the drive like the Niagra!
Threw the Merc muffs away!

I'm with Formula31. Doing it that way takes just minutes.

I talked to a mechanic today and he said the same thing as Dennis. There's probably some kind of air leak that's breaking the suction. I was going to check the short hose between the drive and the transom plate, I didn't think of the gasket inside of transom plate.

Bill,

I'll assume it was me who talked you into replacing the impeller. Sorry it wasn't the fix.

ed

Years ago I had the same problem getting anti freeze through to the engine:( Since then I put my 5 gallon jug on an 8' step ladder along side the boat. I can reach it standing in the cockpit. When I switch from the h2o to a/f the hose turns color (of the a/f) and away it goes.:D