Low Revs

[Mugs]

Hi All I recently Purchased a Lavaranos 36 here in South Africa, It has a Volvo Penta 2003T, THe first Couple of times I took it out it ran fine, until something blocked the Racor, I bypassed the Racor and now when in Gear I only seem to get about 2100rpm in Neutral it I get well over 3000rpm. Then the other day I was out and there was a horrible clunking sound. I immediately shut down and sailed home. however when back at the Marina all seemed fine again in gear and neutral.
Any Ideas?

[HappyMdRSailor]

Welcome to CF Mugs!

Well... The horrible clunking part is disturbing huh???

Your problem started with fuel delivery, and remains to be a problem, so we can pretty much guess it's still fuel delivery!

You've got junk in your tank, and it needs to be cleaned... The low rev condition now is either a secondary filter is restricted, or you have enough crud in the tank restricting your pickup tube...

Try the old trick of running on a clean jug of fuel... If you are performing correctly, you need to clean out the tank, and either ditch your fuel or polish it...

Give us a better description of the clunking noise...

[Mugs]

Thanks, I cleaned and put new fuel in about a month ago, I will be changing the secondary filter this wknd, however in neutral I easily run the engine at full revs,

The Clunking sound is the big issue, It it dos not seem to happen in gear at full throttle tied to the berth so am stumped. I will be taking the local mechanic for a test run tomorrow to see if it happens again. It never happened in neutral but did in both fwd and reverse and only about 30 minutes of motoring.

[HappyMdRSailor]

Originally Posted by Mugs

Thanks, I cleaned and put new fuel in about a month ago, I will be changing the secondary filter this wknd, however in neutral I easily run the engine at full revs,

The Clunking sound is the big issue, It it dos not seem to happen in gear at full throttle tied to the berth so am stumped. I will be taking the local mechanic for a test run tomorrow to see if it happens again. It never happened in neutral but did in both fwd and reverse and only about 30 minutes of motoring.

By "cleaned" do you mean physically scrubbing the tank???

Why not replace your secondary before the test run???

How much time was between "ran fine" and your problem?
(dirty bottom, fouled prop, problem with folding prop)?

One BIG clunk... or repetitive clunk... clunk... clunk....?

[Mugs]

The clunks were repetitive up to the point the engine seemed to stall.
I will certianly change the secondary filter prior to the test run. I have checked the bottom and prop all seems good.

I also get dark colored exhaust water when at 2100rpm which is full throttle, the mechanic seems to think I might be overpropped, but this has only started since the initial fuel issue.

[HappyMdRSailor]

Originally Posted by Mugs

The clunks were repetitive up to the point the engine seemed to stall.
I will certianly change the secondary filter prior to the test run. I have checked the bottom and prop all seems good.

I also get dark colored exhaust water when at 2100rpm which is full throttle, the mechanic seems to think I might be overpropped, but this has only started since the initial fuel issue.

Hmm.... I think some of the junk in your tank played havoc with your injectors then.... Unless there is another "new additional load" on your engine output like totally mispropping... Black exhaust is too much fuel...

I think you're getting giant dumps of fuel in 1 to a few cylinders...

Hopefully a diesel guru will jump in here and either call me a dummy, or confirm for us...

[HappyMdRSailor]

PS:

Injector rebuild wouldn't hurt ya... about $100 ea in the US... I think you're going to need a special tool to pull the Volvo one's... Not sure...