Overheating Volvo shaft seal

The seal was fitted by my engineer at Thornham but as far as I know there was no cup supplied or required for yachts. Certainly it has not been mentioned by other friends who have Volvo seals fitted when discussing the overheating.

I mentioned water injection as a solution as that was mentioned as an option by the above mentioned engineer. Apparently, of the dozens of Volvo seals fitted by him over the years, he has only come across one boat that had to be so fitted (-a Sadler 32/4? I believe) and that solved the problem.

Finally, again as far as I know, the type of rubber Volvo shaft seal that I have fitted only comes in 25mm form (the tolerances quoted allow for a 1" shaft) so I suspect the one inch seal mentioned by Seajade is of a different type IMHO.

Rgds, Nigel
 
I agree. I have a pipe that is connected from a (separate) sea cock to the seal. As the boat moves forward, water is forced through the pipe to the seal and constantly 'lubricates' it. The outboard end of the sea cock has a 'scooped' strainer attached (I haven't yet sussed how to attach an image, but can e-mail one if you send a pm or e-mail).
I have been following this thread with interest as I too have a Beneteau with one of these seals, but it is very difficult to get to the seal without removing a panel above the bearing and climbing below the cockpit floor. Needless to say I have never done this having just run the engine!
However, I intend to check this after a run in the next couple of days, and will advise on the temperature of my seal.
 
I guess it may be just for motor boats, I have had 2 motor boats with Volvo shaft seals and both had "cups" on each shaft and they were about an 1" or 2" back from the shaft exit. We had twin 230hp engines and ran hundreds of hours at 20knots or more with no problems.
I had never seen them before and was told it deflected water back into the tube, it seemed to make sense as I would have thought any water would be "sucked" out by the forward motion of the boat.
It maybe worth checking if you can fit them?
 
Having discussed matters further with my marine engineer I have decided to take up the 'water injection' option. I am told it is a fairly simple task. Fitting is planned to take place in about a fortnight. Will report back with results.

Rgds, Nigel
 
on the benes the stub of the shaft housing that the "bullet" is clamped on has a stub on it that the hose is clamped to. the shaft is a loose fit at the inboard end but the cutlass bearing outside the hull is less than half a mill clearance but has splines in it so that the water can enter etc, the rubber bullet acts as a seal and bearing inboard.
stu
 
Engine had service two days ago. Discussed the volvo seal with the engineer and his opinion was that the shaft does get warm to the touch. If you can't keep your hand on it, it is too hot! He also commented that these seals need to be replaced every 5 years.

Took boat out today. Ran at cruising speed (3400rpm, 2.5:1 reduction) for about an hour. On return to mooring checked temperature of shaft. Luke warm to the touch (remember I have a water injection pipe fitted).
 
Following up my earlier post about an overheating Volvo shaft seal I can report that water injection does seem to have solved the problem. The marine engineer tapped a supply into the output pipe from the raw water impellor and led it back to a brass fitting in the glass fibre moulding (through which the shaft enters the boat and to which the rubber stern gland is clamped). Some warmth is still evident near to the lip seals but that is probably to be expected and is nowhere as bad as it was before. I can only surmise that insufficient water was getting to the gland from outside the boat due to the design of the boat, a bilge keel Moody 336.

I understand that some of the Southerly range are also fitted with this sort of arrangement.

Rgds, Nigel
 
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