Accretion problem

[Imagine]

After engine has been running for some time and I put it in neutral to go in reverse it will not rev up for a minute or so which makes mooring a big problem.i would be happy to hear your ideas

[Scorcher IV]

Will the engine rev normally with the neutral button engaged?

[Imagine]

Yes it will Rev up in neutral but will not in gear when engine has run for 20mins or so.i would be overjoyed if you have any clues thanks martyn

[geoff]

Maybe a clogged filter causing fuel starvation.Geoff

[Imagine]

Yes that's what I thought so changed filters and fuel and cleaned tank but I was disapointed

[Lyra]

This sounds odd - when going from neutral to forward it reacts immediately and when going from neutral to reverse it hesitates?
If I did not understand correctly and it hesitates in both directions then I would look at the exhaust mixing elbow - could be partially clogged.

[Impavidus]

This sounds odd - when going from neutral to forward it reacts immediately and when going from neutral to reverse it hesitates?
If I did not understand correctly and it hesitates in both directions then I would look at the exhaust mixing elbow - could be partially clogged.

Odd. Very odd. I would have said the same 
What engine do you have and when did you last check the elbow?
Do you get any smoke if you rev the engine hard in neutral? If you get black smoke or soot its the elbow. 
It may be the fuel tap is partially blocked.... It sounds like a fuel problem.
Or the cams on the throttle body are not set to pull the cables the same distance in forward and reverse (these can stretch or become dislodged at the ends)
With the engine off, check that the throttle cable travels the same distance in forward and reverse at the pump body.


Ant.

[Craig]

Could there be something wrong with the reverse gear in the transmission???

Can't see any other way these systems could exist.

Craig
"Shirley Valentine"
Gold Coast
Australia

[mikeiso1192]

What type of propellor do you have?

I have a Kiwi feathering prop and I find that when changing from forward to reverse the engine is quite slow to pick up.
This is due to the fact that in that transition the blades on the prop have to flip to provide reverse thrust and this is set at a courser pitch which can make the engine labour and pick up slowly.

The upside is that when reverse thrust is on it is very effective.

Mike

[Imagine]

It has now got to the stage that after 10 minutes running it will not acellerate at all.i have taken injector pump of today to be checked but I am almost certain it is ok.this exhaust  reply is interesting but how can it clog and I have no smoke at all from engine.when it is running it runs sweet allay if I want but once put in neutral that's it. It is a Volvo penta 2030

[Impavidus]

It has now got to the stage that after 10 minutes running it will not acellerate at all.i have taken injector pump of today to be checked but I am almost certain it is ok.this exhaust  reply is interesting but how can it clog and I have no smoke at all from engine.when it is running it runs sweet allay if I want but once put in neutral that's it. It is a Volvo penta 2030

Imagine.
It sounds like fuel problem but could be the exhaust elbow. The latter if not checked will have a catastrophic effect on your engine. If the exhaust elbow has been on the engine 4 years or more you can almost be certain it is blocked or partially blocked. While there may be good water flow through the raw water system and out the exhaust pipe the elbow will have a build up of carbon deposits that can choke the engine. This eventually builds up to a point that it stops the engine breathing and sometimes (but not always) produces black smoke or soot when the engine is revved hard. Eventually all the water cannot get out and some is forced back into the exhaust manifold as the engine is shut down. It then gets past the open exhaust valves and sits on the piston(s) seeping past the rings and into the oil...... Scrap one engine. It is the most common cause of engine failure in marine diesels.

Even if its not the cause you should check every other year for build up. From memory your exhaust elbow is very easy to remove and for the £4.50 a new gasket will cost I would recommend a look.

Elbow.
Remove the injection hose elbow from the top of the elbow by removing the jubilee/hose clip, that's the small one on the top of the elbow not the big one on the back of the heat exchanger.
undo the hose clip on the exhaust where it joins the elbow and pull the hose from the elbow. This will be a tight fit and will have corroded in position it can be a ******* to get off but will go back on easily if you rub some fairy liquid on the elbow before re-assembly.
Undo the 4 bolts that hold the elbow to the exhaust manifold and gently wiggle it off of the gasket.
Inspect the elbow from the gasket side. It should have a minimum of 75% of its original diameter. That's about 40-45mm on the 2030. You can try to clean it up if its blocked or very reduced, but to be honest its best to just change it as the cast iron will be rotten under the crud and deposits.
Replacing is just the reverse but with a new elbow and gasket.

Fuel.
The only time I have heard of there being an injection problem on a 2030 is when water has got in the tank and forced through the pump and injectors. Even then they can cope with some moisture if it is sorted quickly. The symptoms for water in the fuel are; engine surges when running, will not run evenly, will not rev, lack of power water in the fuel separator. (bottom half of the pre-filter. The most common cause of water in the fuel is the filler cap on some Bavaria's is deck mounted. The O ring on the cap is the only thing keeping the sea and rain out of the tank. Check and replace every 2 years and add a little silicone grease to the cap so it seats tightly.
If the filters are clean and fuel is getting through then its most likely to be the amount of fuel is restricted. The "prime suspect" is the fuel line at the shut off valve in the aft cabin or the fuel pick up in the tank. Either can be clogged with gunge or plastic swarf from the tank fittings when they were drilled or stuff that's got in the tank over the years. I would remove the valve and clean that first its the narrowest point in the system before the filter and its a common problem.........

Hope this helps, let us know how you get on.

Best regards. 


 Ant.   



     



     

[Salty]

This might seem like a daft question, but is your fuel valve actually switched to on, i.e., valve handle in line with the fuel line and not at 90 degrees across it ?

The reason I ask is that there have been several occasions where I have actually run my engine MD2020 for periods of an hour or more with the fuel valve actually shut. Last time I did it and was able to confirm that the valve was shut was last year when I left my mooring and went around to the fuelling pontoon to take on some more fuel in readiness for a weekend excursion. I ran the engine for at least an hour before leaving the mooring, arrived at the fuelling pontoon, took on forty litres of diesel, re started the engine and left the berth to head to my mooring. Engine started easily, I backed out away from the pontoon, and at that point the engine refused to accelerate. I limped back to my mooring, took the engine out of gear and it accelerated happily and then promptly died. Checking around I discovered that the fuel valve was shut.

At the end of last year I took my boat to a yard some thirty five miles away, and would have sworn that the fuel valve was open. On arrival off the yard where the boat was to go ashore for the winter, I picked up a temporary mooring for the night to wait for the high tide next morning, but having slowed the engine and then put it into neutral as I drifted in to the berth and had no need to go astern or Rev the engine. Because of the intended movement in the morning, the engine fuel valve was not touched that evening. Next morning on the assumption that the fuel valve remained open, the engine was started and I headed towards the hoist, but before getting there the engine died, and on checking I found the fuel valve shut. During the previous day's passage the wind had been too light to sail, and the engine had run continuously for the passage, but it was noticed that the revs which had been set at 2500 had fluctuated between 2100 and 2500, and this was not normal.

Once the fuel valve was opened, the engine restarted after about three attempts and the lift out had only been delayed for about five minutes.

Why had the engine run for the full length of the sea passage with a fuel valve that must have been shut, I have no idea, and the jury is still out. But this last winter I fitted a tell tale indicator at the helm which would light up if the engine panel was switched on but the fuel valve was shut. Also since then I've not returned to my original habit of shutting the fuel valve before leaving my boat. It now stays permanently switched on.

Since then the engine has behaved perfectly, but the big question is why would it have run for all that time with the fuel valve shut. As for the acceleration bit, it only misbehaved on that one occasion after coming off the fuelling pontoon and after the engine had been run by that time for almost two hours with the fuel valve shut.

[geoff]

if it is a Kiwi prop and it has not been serviced recently it may not be going into reverse properly. They can get stuck at 45deg pitch in reverse which would produce your symptoms. Geoff

[Osprey]

It could be the Kiwi prop.  We had the same problem and it may be the silt in our river - the Orwell.  In the end Kiwi refunded our money and we changed prop and solved it.  This is a known Kiwi problem.

[Imagine]

You were right impervious it was a piece of plastic in the pipe to lift pump restricting flow at pressure.thanks for some great advice

[dawntreader]

Why had the engine run for the full length of the sea passage with a fuel valve that must have been shut, I have no idea, and the jury is still out.

This may seem incredible but I assure you it's true. We left Antigua - motored out - and sailed directly towards the Azores. When we reached the 'Azores High' the engine was switched on again. It ran for another 24 hours before failing. On checking I found the fuel switch 'off', so I hadn't turned it on leaving port. However, I had fuelled to the very top of the filler cap before leaving and I now believe that the engine ran until the fuel that was above the fuel return pipe from the injectors was used up. This would mean that the injectors took fuel 'backwards' through this pipe. Feasible?

[Salty]

Why had the engine run for the full length of the sea passage with a fuel valve that must have been shut, I have no idea, and the jury is still out.

This may seem incredible but I assure you it's true. We left Antigua - motored out - and sailed directly towards the Azores. When we reached the 'Azores High' the engine was switched on again. It ran for another 24 hours before failing. On checking I found the fuel switch 'off', so I hadn't turned it on leaving port. However, I had fuelled to the very top of the filler cap before leaving and I now believe that the engine ran until the fuel that was above the fuel return pipe from the injectors was used up. This would mean that the injectors took fuel 'backwards' through this pipe. Feasible?

I too had wondered the same thing, but is it possible for fuel to run in the reverse direction through the return pipe, pass in to the injectors and through to the combustion chambers and so allow the engine to run?
On the occasion I had referred to our passage time with the engine running continuously was about six hours, and like Dawntreader I'd filled the fuel tank right to the top so that the fuel filler pipe was full of fuel, and therefore the fuel was above the point where the return line entered the tank.
During the sea passage the engine revs hunting up and down over some four or five hundred rpm were the only indication I had that something unusual was going on.