Dumb diesel question

[mireland]

This is the sort of question that is good for everyone's ego except my own but here goes....

When the boat goes back in the water do I need to prime the cooling system in some way or will the impeller do the business? I have DV36 Bukh - freshwater cooled in case that is of any significance.

Thanks and you can pick yourselves off the floor now.

 

[iangrant]

Not dumb at all - I had a volvo that needed priming, even after heeling sometimes, a yanmar that didn't and now a volvo that doesn't.
I would thake the lid off the water filter and fill it up though, save running the impellor dry to start off.

Keep asking, you will get all the help you need from the lot on here.

Ian

 

[jerryat]

I agree with Ian, not a daft question at all. I always fill the filter on my Bukh 20 before starting for the first time each season. Better safe than sorry and those damned impellers cost the earth don't they?!!

Cheers Jerry

 

[Close hauled]

My Volvo sometimes needs priming - I do just what iangrant did and top it up through the water filter.

 

[Anonymous]

[ QUOTE ]
My Volvo sometimes needs priming - I do just what iangrant did and top it up through the water filter.

[/ QUOTE ]Have you checked the thickness of the plate over the water pump impeller? It might be worn by a few thou in which case you'll feel a ridge. Try turning the plate over to present the unworn side to the impeller.

 

[bluedragon]

It may depend on whether your pump is above or below the water level. If below, then in may well self prime when you open the seacock. That's the case with mine, but there again it's an old Sabb which is a bit different to modern engines.

 

[mireland]

Thank you all very much for your good advice. I will not risk a dry start now!

 

[Alastairdent]

If the intake filter is above the pump, then the pump shouldn't be dry.

 

[cliff]

[ QUOTE ]
This is the sort of question that is good for everyone's ego except my own but here goes....

When the boat goes back in the water do I need to prime the cooling system in some way or will the impeller do the business? I have DV36 Bukh - freshwater cooled in case that is of any significance.

Thanks and you can pick yourselves off the floor now.

[/ QUOTE ]DV 36's self prime - good old Bukh - however I would remove the strainer, clean it and reassemble BEFORE putting the boat back in the water. There is no need to prime unless you have to EVERY time you start her in which case the impellor / cover is knacked.
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[iangrant]

See it wasn't dumb.

Remember most of the folks on here have done it broken it, researched it then fixed it.

Good luck

Ian

 

[peterb]

On lots of boats water poured into the filter just runs out through the sea cock. Shut the seacock, prime the filter and replace its lid, start the engine then immediately open the seacock and check water flow.

 

[jerryat]

Yep! That's exactly the way I do it too!! Only needed at the start of the season, though I do close the engine seacock whenever I leave the boat, so the water in the supply hoses doesn't creep out between uses.

Cheers jerry

 

[Anonymous]

I wouldn't accept that arrangement. What if the engine is needed at sea in a hurry, in bad weather? It's a positive liability. There is no reason why an impeller pump should need all that priming unless the impeller, the pump or the housing plate are worn, or, maybe, the wrong ones fitted. An impeller should lift several meters easily, even when dry. /forums/images/graemlins/confused.gif

 

[Robin]

No you should not need to do anything except turn the key. Anything else is a means of overcoming a defect that should not be there.

If the pump doesn't self prime it is getting tired and probably is sucking air via the seal between the faceplate and the side of the impellor. Either buy a new faceplate or reverse the existing one having cleaned off any paint etc, this will only work if there isn't a load of engraved part numbers, makers name etc on the reverse side. As a temporary measure you could try rubbing down the faceplate wirh wet/dry held against a very flat surface (like a sheet of glass, you will be able to see concentic grooves worn in the faceplate and it is these you are trying to minimise if not remove. The same effect can arise from the back face of the pump being worn but that seems to be less of a problem, just as well because the solution would be a new pump....

It it is is just a general question and you haven't actually had a problem then just turn the key and go. It helps however to reduce wear on the expensive impellors if you put a little waterproof grease on the vanes when you put it back after service. By the way the thickness of the paper gasket is important, too tin and you get too much friction (it will get hot) and too thick and the pump will suck air between impellor and faceplate - home made brown paper gaskets are not good unless you are sure they are exactly the right thickness (really thin-ness!)

See - not a stupid question at all!

Robin

 

[fireball]

Well - on both boats - Volvo and Yanmar - we've not bothered priming the water intake - opening the inlet valve (before starting) is enough to get a head of water into the filter and through to the impellor...
We even had a duff impellor at the tail end of the season - and the head of water was enough to give it just enough push to keep the engine cool - but not heat the water tank /forums/images/graemlins/frown.gif (raw water cooled/heated)