Water pump wont pump on diesel inboard

purplegoanna, Apr 20, 5:03am
volvo penta inboard diesel motor in his lordships boat wont pump water through, all he did was change the rubber wheel inside with the exactly the same part but new.any thoughts, hes had it apart 3 times and cant work out why it wont pump water thru.hes abit of a mcguyver man but this has him stumped.airlock! (was my thought).if he cant go fishing over easter i may have to kill myself! pmsl

intrade, Apr 20, 5:21am
fill it up with water from top dont let the impeller run dry for to long or it be rooting the new impeller

johnf_456, Apr 20, 8:42am
Try the local service center most should give free advice as part of PR.

unclejake, Apr 20, 9:18am
The new impeller is probably burnt already, but perhaps he has put a gasket in upside down or has rotated the impeller vanes the wrong way during re-assembly.

It makes sense to place the old impeller (which will have time curved vanes) next to the new one, and to look very hard at them both. It would be easy to get either impeller upside down so have him look very hard for imprints from the running washers on the old impeller (the nylon washers on each side of the impeller body)

Intrades suggestion of filling the system up from the top is a good one (if possible). Does the boat live in the water, and if so are you confident that the through hull water pick-up is not blocked!

purplegoanna, Apr 20, 9:58am
new propeller is fine looks like the day he got it out of the packet.will check on the other thoughtshe said the impellor washers are what he thought of today so pulled it apart and rechecked and they were put in correct.

intrade, Apr 20, 7:43pm
only other reason would be the pump shaft is not spinning or the impeller is not driven by the shaft. you should turn the engine over by hand slowely to check that also.

jerichord, Apr 20, 7:51pm
prime it first, from the top to get ALL of the air out

intrade, Apr 20, 8:24pm
i said that ages ago

dunwoody, Apr 20, 9:24pm
Thats the problem. impellers dont like sucking water while there is air about.
the inltakeand outlet should be above the pump so that the pump stays full of water at all times.

topper, Apr 20, 10:58pm
Not meaning to belittleany one, but, is the sea cock open!Many inboards have a sea cock at the hull skin fitting for the incoming raw sea water.
Just my 2 cents worth.

321mat, Apr 20, 11:42pm
Well, I think it's time to start rowing.

Or swimming.

purplegoanna, Nov 23, 5:49am
hes just looked at the that and wondering if the sea cock pipe has perished enough to let air in aswell as water