Strainer empty, is this normal?
- Thread starter Jokani
- Start date
Jokani
Well-Known Member
VicS
Well-Known Member
Its not relevant to the current thread but if you are not sure about the ID of the engine look along the port side of it. There should be an ID plate on the crank case.
The water cooled gearbox makes me suspect it might be an MD11C but I dont know for sure that it was not fitted to the MD2B
pvb
Well-Known Member
The Centaur I bought in 76 had an MD11C engine fitted. The MD2B was replaced by the MD11C in 75.
pvb
Well-Known Member
This is the classic sign of an air leak on the strainer lid or one of the hoses. It's nothing to do with the pump, so hopefully you can cancel the order for a new one. The strainer empties when the engine's running because the strainer is then under a slight vacuum, and a tiny air leak allows air to enter.
Jokani
Well-Known Member
I have just checked the survey form early this year, he was a thorough chap, it states 'ENGINE / SERIAL NO: Volvo Penta MD2B / 53350.'
But, I have previously encountered a date/part discrepancy. I ordered a cutlass bearing from Trafalgar Yachts, I was unsure of the size 1" or 25mm, TF said that it had to be 25mm as they stopped put the 1" in 1974. It, turned out to be 1" :-( Not long after I bought a vernier caliper!
But it also states:
NAME: GEMINI.
REGISTERED NUMBER: SSR 10483.
DESIGN: Westerly Centaur.
DESIGNER: Laurent Giles and Partners Ltd.
BUILDER: Westerly Marine Construction Ltd.
BUILDER’S NUMBER: SOU221075.
YEAR OF BUILD: 1975
So maybe it is a '75, but it was sold to me as being built in '76
This is what was on the 2008 survey:
So maybe the hull was registered in '75 an the boat built '76
But, I have previously encountered a date/part discrepancy. I ordered a cutlass bearing from Trafalgar Yachts, I was unsure of the size 1" or 25mm, TF said that it had to be 25mm as they stopped put the 1" in 1974. It, turned out to be 1" :-( Not long after I bought a vernier caliper!
But it also states:
NAME: GEMINI.
REGISTERED NUMBER: SSR 10483.
DESIGN: Westerly Centaur.
DESIGNER: Laurent Giles and Partners Ltd.
BUILDER: Westerly Marine Construction Ltd.
BUILDER’S NUMBER: SOU221075.
YEAR OF BUILD: 1975
So maybe it is a '75, but it was sold to me as being built in '76
This is what was on the 2008 survey:
So maybe the hull was registered in '75 an the boat built '76
VicS
Well-Known Member
Fair enough MD2B it is. The change over from production of the 2B to the 11C was 1975 according to VP's website
If you dont have an owners manual then you can download one from http://www.volvopenta.com/volvopent...lication_search/Pages/publication_search.aspx
and a workshop manual from http://www.bluemoment.com/downloads.html
Plum
Well-Known Member
Jokani
Well-Known Member
Frustrating!
I purchased a replacement Vetus strainer and lid with a new 'O' ring, fitted that this weekend.
The strainer has double clips on both the inlet and outlet, I refitted these, and used LS-X jointing compound to be doubly sure of an air tight connection.
Unfortunately the problem remains :-(
At idle the strainer remains full, but under load it empties ARGH!
I can only think of two things left to try:
1) Replace water pump
and if that does not work
2) Replace both inlet and outlet pipes
Determined to cure this, and have arranged with the yard to keep in the water for a couple more weeks whilst I try.
I purchased a replacement Vetus strainer and lid with a new 'O' ring, fitted that this weekend.
The strainer has double clips on both the inlet and outlet, I refitted these, and used LS-X jointing compound to be doubly sure of an air tight connection.
Unfortunately the problem remains :-(
At idle the strainer remains full, but under load it empties ARGH!
I can only think of two things left to try:
1) Replace water pump
and if that does not work
2) Replace both inlet and outlet pipes
Determined to cure this, and have arranged with the yard to keep in the water for a couple more weeks whilst I try.
RichardS
N/A
This is really strange. The water in the strainer must be being displaced by air. It can't be a vacuum unless the seacock is closed or blocked but then you would go no, or very little, water out of the exhaust.
The only thing I can think of, and if the boats not underway it seems incredible, is that somehow air is being sucked in with the seawater. The seacock would have to be very near the waterline or something even weirder for this to happen!
Try replacing the hose from the seacock to the strainer with transparent hose to see inside. Any old cheap polytube will do as it's only temporary. You might be able to borrow a short length from the yard. If there is air coming in you should see it.
Richard
ghostlymoron
Well-Known Member
Take the inlet hose off the seacock and put it into a bucket of water. It sounds like there could be a partial blockage at the seacock or something.
Pagetslady
Well-Known Member
If it's any consolation mine is the same, there must be a vacuum in the strainer for the water to be drawn through otherwise it would only draw air.
I have the Vetus clear topped one which is just on the waterline it's connected to a Beta 35 which runs at normal temperature I can see the water coming into the the strainer but it never fills.
Does this mean the pump is trying to pump more water than it and get in through the seacock if I fitted a strainer below the water line whorls that always be full?
Mike.
All the pipe work and seacock is 25 mm bore
I have the Vetus clear topped one which is just on the waterline it's connected to a Beta 35 which runs at normal temperature I can see the water coming into the the strainer but it never fills.
Does this mean the pump is trying to pump more water than it and get in through the seacock if I fitted a strainer below the water line whorls that always be full?
Mike.
All the pipe work and seacock is 25 mm bore
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Kylora
Well-Known Member
I don't think that it will fill on it's own. At the start of the season, I have the seacock closed, remove the lid from the strainer, fill the strainer using the kettle, Vaseline on the o ring and threads and close it up. Always stays full. I close the seacock when I leave the boat. Top of the strainer sits above the static water line, but not by much, less than the instruction say.
Ash
RichardS
N/A
But the OP's strainer is full until he starts the engine so he doesn't need the kettle trick.
Richard
30boat
N/A
I said it before in this thread but no none took notice.I once resited my striner higher up in the engine compartment and experienced the symptoms the op is having.Once I put it back in it's original(lower) position all went well.
Heckler
Well-Known Member
h
You can see the air bubble extending to where the leak is if you look carefully!
S
Mine used to do it, it was the O ring and overtightening of the wing nut had distorted the lid. I put a new O ring in and put an O ring under the wingnut washer. Fixed!
You can see the air bubble extending to where the leak is if you look carefully!
S
Jokani
Well-Known Member
Just to confirm, the strainer is fitted at the waterline, if I remove the lid it does fill almost completely. I replace the lid and start the engine, everything works as expected. It is only when the engine is under load that the strainer empties. If then switch the engine off, the strainer remains empty and a vacuum has formed, if I release the lid the it fills again.
VicS
Well-Known Member
It cannot have formed a vacuum, or it would suck water in via the inlet seacock and refill itself.
It has simply filled with air drawn in through a small leak while the engine was running. The leak will almost certainly be above the waterline or there would be some evidence ( just dampness perhaps , no more) of a leak below the waterline when the engine is not running.
The only place where that can be is the top cover of the strainer, as that is the only bit above the waterline.
Therefore examine the cover for any cracks etc, replace the seal (and the seal on the retaining nut if it's the type with a retaining nut), coating the seal(s) with Vaseline or similar.
Avoid over tightening the cover, or its retaining nut, as that is a well known cause of leaks.
30boat
N/A
Strange.It stands to reason that if you had a vacuum in the strainer it would be filled by seawater.Maybe what you have is positive pressure that's not allowing water to come in?
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Jokani
Well-Known Member
Thanks for you advice, what you say makes complete sense.
I have not noticed and dampnesss, but I will see if I can wrap tissues around strategic points up to and including the water pump, and leave overnight.
I did replace the lid and seal at the weekend (it's a Vetus with a clear lid), but I'll add some vaseline as well.