Loss of engine water at higher revs

S

Sundowner 39

Well-Known Member
Joined
10 Dec 2010
Messages
153
Visit site
Hi All
I have a TAMD41B Volvo Penta...runs well and starts on the button....but on occasion at at revs over 2250 the engine water stops coming in...no water in the stainer .
I have fitted a new water pump / impellers / and cleared the impeller debris from the cooler stack / new water piping and strainer and O rings on the gear box in and outlets as in coming water goes there before the pump.
Went out for a test today ....no change...am I looking in the wrong place ?
 
Sundowner 39 said:
Hi All
I have a TAMD41B Volvo Penta...runs well and starts on the button....but on occasion at at revs over 2250 the engine water stops coming in...no water in the stainer .
I have fitted a new water pump / impellers / and cleared the impeller debris from the cooler stack / new water piping and strainer and O rings on the gear box in and outlets as in coming water goes there before the pump.
Went out for a test today ....no change...am I looking in the wrong place ?
Click to expand...

Check that you have a constant rise (without dips) of the water pipe from inlet to waterpump have seen this causing problem.
 
Seems odd that the gearbox coolers are sited before the pump, pumps usually push better than they pull, would it be easy to re plumb the system so the water goes straight to the pump to then be forced round all the coolers?
 
Have you done any work on the water inlet, the only time I have seen a similar fault was when the water pickup had been installed facing aft so at a certain speed the waterflow under the hull created a negative pressure stopping water from going up to the pump. This is the normal installation on sail boats as they don’t go fast enough to create a negative effect, but power boats can experience this.
 
Thanks Beamisken ...my thoughts exactly but this is a 1992 build and has original layout.....however I will think about change......
Spannerman....same applies but again it is possible to make a change......currently there is just a hole in the steel flush with the hull.....although she has 200 hp she is not a greyhound but faster than my last yacht ...so again I will experiment on next lift out.

Today I noticed there seems to be a moment of vacuum in the strainer when it goes from bubbling away to almost flat calm but by opening the strainer very slightly happy bubbling returns as pressure is released.
 
Re gearbox coolers, don’t change the design, they are correct.
Another vote for checking the water inlets under the boat, possible someone has fitted new sea cocks and skin fittings and put them on backwards
 
Hi Kashurst
The seacocks may have been changed but they match the rest so maybe not !.....there are no skin fittings as such only a pipe welded to the hull and threaded to receive a fitting.....it is becoming a bit of conundrum ....I would just hand it over to Volvo but they have no idea either and at 70 plus euro an hour that might be V expensive.....I am in Utrecht at the moment.
Thanks
 
The water pioe on the turbo is freshwater and only needs bleeding if the coolant has been drained.
Back to water inlets,, power vessels usually have a forward facing scoop with a screen to deflect debris.
 
No, as spannerman described the turbo cooling is on the fresh(anti freeze) side and nothing to do with raw/sea water cooling issues.
 
Hi ....when the engine was serviced the coolant was drained and as I was watching ...they did not drain anything on refill just ran it up to temperature and topped up.
Can anybody tell me roughly where the drain is ...I will also try google for pictures.
Long shot maybe but needs doing anyway.
 
You just slacken the hose coming from the top of the turbo to the expansion tank and let any air out so you don't have an air pocket in the turbo, just like bleeding a house radiator.
 
You must log in or register to reply here.

Share this page

Top