New Impeller -- Universal M 35 B

[GunnerNell]

I just changed the impeller (Sherwood) in my M35B -- my first time -- and upon start-up, there was no water coming from the exhaust port. I shut it down within the first minute, then tried again. Still no water, so I shut it down again.

1) Is this normal? IOW, do I have to run the motor for several minutes before water will start pumping? Or, do I have to "prime" the system somehow, and if so, how the heck do I do that?

2) Does the fact that I ran the motor with the stopcock closed for about 5 minutes last time out change anything? (Note that the old impeller was complete when removed -- no missing vanes or pieces at all. I replaced it because the boat had sat for almost a year before we bought it, and yes, a few of the old impeller vanes had deformed.)

Thanks in advance for any assistance.

 

[Don S/V ILLusion]

Check the obvious stuff first, e.g., air leak on the pump plate. Assuming you have a gasket on the housing, did you replace it? Did you run the engine with the plate off to visually inspect the impeller is turning?

 

[GunnerNell]

Didn't check while running, but this impeller doesn't have a plate -- it's more of a cup within which the impeller turns. Oddly, there was no gasket other than an O-ring, but the kit came with a paper gasket, so I installed the gasket and the O-ring. Maybe I should remove the gasket?

 

[Don S/V ILLusion]

This is one of those things that the internet isn't good at - diagnosing problems. It could be as simple as two gaskets( the O-ring and paper gasket) causing a leak, the wrong impeller, impeller improperly seated or a myriad of other causes.

Maybe others might offer some guesses

 

[GunnerNell]

Understood. I'm going to remove the paper gasket and try again. I double-checked the schematic in the manual, and it does not show the paper gasket where I placed it. That would explain why there was nothing there when I dismantled it. Duh. I'm pretty confident the impeller is the right one and is properly seated. This time, too, I'll have someone listen for hissing as I start the engine. Thanks much for your help.

 

[Tim C350 April IV]

Silly question but did you open the seacock?

 

[GunnerNell]

Yep, I had opened it.
Turns out that Don's a genius. I went back in and removed the paper (or whatever) gasket, and that's all it took. Just to be sure, I re-oiled the O-ring and re-lubricated the impeller front, back, and vanes with dish liquid (Palmolive, if you must know), as recommended by the boatyard guy who talked me into replacing the impeller in the first place. In watching the exhaust, I was happy to see that little 35 pumping out suds. Thanks Don. I appreciate your help.