I just wanted to report back on this. After taking the exhaust elbow off it’s clear that it was very much towards the end of its useful life.
An engineer here in Rotterdam tried to clean it up but it was disintegrating. Hopefully, a photo is attached.
We decided to opt to replace as this piece failing in any circumstances would be less than ideal. A new elbow was €500 inc gaskets + fitting (we were out of the country..).
With the new elbow fitted the bleed vent now only pushes water out at high RPM ±2,000. At idle there’s no water coming out of it. From reports on cruisersforum this is much closer to normal behaviour than the jetski like telltale we were seeing.
The main exhaust also now has a fuller and more constant flow of water.
@Alasdair “The actual exhaust with coolant seems to be discharged in bursts”
This is what our exhaust was doing pre-new elbow. Now it’s more constant.
“If the exhaust need cleaning surely there would be a noticeable reduction in power?”
It’s quite possible/likely that the backpressure has led to a power reduction. However, as we’ve only had the boat for just over two years, so I don’t have a benchmark to work against.
When we next take the boat out I’ll see if there’s any difference in water speed.
If you’re seeing a constant stream at idle I’d consider taking a look at the whole system.
- This reply was modified 1 year, 8 months ago by Duncan Malcolm.