Bellows, but not Barnacles !!???

[msimms]

Well I don't think so, no evidence of any crustaceans that i could see. The images are of a bellows that's been in the water for about seven months but we believe failed on it's first outing. The replacement has lasted around three hours running (on the plane) but we haven't been able to inspect it yet as water is too murky. We know it's gone as the exhaust is no longer exiting from the correct place.

The bellows are not Volvo but appeared to be of good quality when fitted. All the others were in perfect order when we were lifted last month. Due another lift week after next so will see if it's failed in the same fashion. Any ideas why I can't make a bellows last more than a few hours? Could the exhaust be partially blocked causing them to explode!

 

[epervier]

almost looks as though the exhaust isn't cooled enough, ie not enough water coming through, and hot gases destroying the bellows, in stark contrast my exhaust bellows after 2 years look just as good as the ones I replaced them with.

 

[oldgit]

"lmost looks as though the exhaust isn't cooled "

Agree,looks like something is drying out heat or mebbie neat fuel is leaching out whatever makes bellows flexible ?

 

[GrahamHR]

What's that L shaped bracket for, is it supposed to protrude like that? ; it looks like it would be rubbing on the bellows when the drive is down and it's being tilted or steered side to side.

Graham

 

[msimms]

"lmost looks as though the exhaust isn't cooled "

Agree,looks like something is drying out heat or mebbie neat fuel is leaching out whatever makes bellows flexible ?

That's something I'd not considered. The bellows is still flexible with no obvious signs of heat damage. I think I'll put a small section in the oven and see how it looks after being cooked up a bit.

I'll check all cooling inlets and pipes when the leg comes off for service. Engine temp guages are normal, the port may be a needles width hotter. Difficult to tell to a degree or two.

This engine is down on power, it will only rev to around 3400 and I can't help feel they are related. If the mechanic can't find anything wrong with the cooling or exhausts I may swap the legs (I guess there not handed) to see if the low power/failing bellows moves with the leg or stays with the engine.

 

[msimms]

What's that L shaped bracket for, is it supposed to protrude like that? ; it looks like it would be rubbing on the bellows when the drive is down and it's being tilted or steered side to side.

Graham

Not sure of it's purpose, they were on my last boat as well. I think they provide protection for the bellows. The damage was more to the side rather than underneath.

I'll check that the angle of the plate is the same on both legs and that there is no undue pressure through lock-to-lock steering.