Volvo Engine no power

[Dignity]

Hi

I have a 2001 Jeanneau 29.2 with a Volvo 19hp engine.
About 2 years ago I hit a massive pile of seaweed while under power.
Since then the performance under power has not been good.
The original problem was anything 2,000 rpm or more gave no additional power just vibration. After many lifts the local mecanics decided the prop needed changing. This was done and although it is much smoother there is still no more power after 2,000 rpm - actually it won't even go about 2,000.
Naturally we made sure the boat underneath and prop are clean.
Before I go back to the mechanics I am trying to get as much amo as possible to finally get it sorted. I can't actually remember what the engine used to rev to so if anyone knows it would be handy.
Many thanks for any ideas.
Andy

[tombed]

Hi Andy,

How does the engine seem, other than it having no power? Noise, smells, exhaust? At a *guess* i would have thought you'd get 3,200 rpm out of that engine.

Also, what happened when you hit the seaweed and immediately after?

Thanks,

Tom

[Dignity]

Thanks for the reply Tom. at least I know now what I'm expecting. The engine is really smooth up to 2000. It was recently serviced as well.
I have had another thought since posting here : The 1/4 tank of diesel left could well be 3 years old (we don;t have far to go to the sea !). I've filled it up and going to try and use it up today.
Andy

[tombed]

3 year old diesel? You'd be best off draining the tank, as running that through the engine could cause you some serious problems.

With the engine being serviced we can safely assume the engine oil and filter have been changed along with the air and fuel filters.

[erps]

Low power/RPMs on a diesel motor is typically from fuel starvation. Once that's ruled out, it gets a little harder to figure out, but start with the easy stuff first.

[JimsCAL]

The full load RPM of most marine diesels is about 3000 RPM. Too main causes for low RPM: prop (with too much pitch) or engine down in power (fuel starvation as erps mentions). Are you sure the yard put the right prop on?

You don't mention what speed you make under power. If you can make 5+ knots, the engine power is probably fine.

[Dignity]

It is definatly better than with the old prop, but I didn't check it was the same. Unfortunaltly I don;t live in the same country as where the boat is, so wasn't around when they did it, but they've always been good so far.

I'm going to sort the fuel out first.

Thanks for all the replies

Andy

[jrd22]

I'm also guessing fuel like Erps said. Try changing the filters, they are probably clogged and restricting rpm when under load.