Volvo 2003 throttle control mystery.

[Muddywelly]

Any help please, as I'm mystified.

I've recently acquired a boat with a 36yr old Volvo Penta 2003 and I'm finding accurate control of revs almost impossible.
I've eliminated control levers and cables as causes by temporarily detaching them and operating the throttle directly by using the arm on the engine.

There is no slack/play in the arm and it moves smoothly with only modest force. Pulling the arm evenly increases revs from idle, 750rpm, anywhere up to 1000rpm, but at that point, the most microscopic movement of the arm lifts the revs which just keep on rising to 1400rpm. To put it differently, when increasing revs, it is impossible to select a rev amount between 1020 and 1390rpm. From 1400rpm upwards the revs once again rise evenly and will remain at whatever level is required.

Going down through the revs is a little better, but there is another 'dead spot' where the revs won't sit between about 1250 and 1000rpm.

Any thoughts or suggestions would be greatly appreciated.

 

[Iliade]

Change the filters etc?

 

[AntarcticPilot]

I'm interested in this; my Volvo 2003 exhibits pretty much the same behaviour, and if it can be fixed, it would improve low-speed handling.

Changing my filters (which I do as required, but usually annually) makes no difference.

 

[penberth3]

A governor problem? Anything's possible at 36 years old.

 

[[70521]]

A governor problem? Anything's possible at 36 years old.

Two boats with the same issue, I suspect not.

 

[arc1]

Mines similar vintage and behaves the same. Have decided to treat it as a feature, and am happy that (touch wood) it starts and runs on demand. Slow speed handling (31 footer) good so not really an issue for me.

 

[jwfrary]

Sounds very normal for these units tbf

 

[Stemar]

Two boats with the same issue, I suspect not.

With engines that old - 30+ years, and a lot of them around still, I'd expect that any issue that can be caused by wear would not be uncommon.

The governor or the rail sticking would be my first thought; it might be possible to do something about the rail, but I doubt if the governor would be an economic repair even if the parts are available.

If I could live with it, I would. If it were a real issue, I'd start thinking about converting beer tokens into engine tokens.

 

[Pete7]

There is a sort of related thread here which gives some insight into the injection system:

Volvo Penta 2003 Cold Start fuel enrich schematics - Cruisers & Sailing Forums

If the mysterious box of springs and levers on the port forward side which controls the throttle mechanism, is open to the engine oil, I would be tempted to do a good oil change, perhaps with one of those flushing oils as well. Next check the injector rod runs smoothly by peering in the hole at the back of the port side after removing the large nut.

Finally turn you attention to the fuel system. Is the fuel tank spotlessly clean? Does the fuel pump have a nut on top to take it apart? if so do so and have a look inside. Diaphragm in good condition and clean inside? We replaced ours recently. Finally check the fuel lines to see if aged or kinked.

Ours has this problem when cold. After a couple of minutes the revs speed up and then its fine.

After the above, take it for an Italian tune up. Ours was much better after a dash across the channel into the teeth of a gale for 14 hours. That run cleared out that engine completely and it ran much better.

Whilst your working on it, take a look at the thermostat, particularly if its a raw water cooled engine. The thermostat is made of a mixture of metals and lives in a hot saltwater environment. You can guess the rest. Another improvement to the time it took to heat the calorifier after we swopped out the thermostat.

Whilst your in there, does the alternator have a tiny little black wire going to the engine block? If so how is that going to handle 40 - 50A charge from the alternator? Replace with a decent 25mm wire.

Bottom line is these are engines are getting on a bit, but they do work and worth nurturing. If the worst happens, well they are always for sale in e bay or boats and outboards.

Pete

 

[Frankklose]

You have to asked yourself "why are these engines for sale" ??

 

[Frankklose]

The wire.
VP has been building two electrical versions. One version has the minus lead on the engine Block. The 2nd version has isolated engine block. Your alternator could be for the isolated version and needs the extra wire for the minus lead. The cables are too small for 50A anyway.
I have a Vp2003T and want to charge Lithium batteries. My alternator has a rating of 90A, in reality for continuous operation max 60A.

 

[Frankklose]

Fuel pump.
The pump is most likely more than 30 years old.
Parts which are most used on a VP200X: Fuel pump and starter motor..
I carry both as spares on board.
Starter motor has a small gear box (helical drive) which consists of 3 tiny plastic gears. I was surprised, that they lasted over 30 years. They would be OK for toys.....but not for a boat engine. ( Starter broke at the entrance of the harbour, sailed into the marina.....it was an experience, Moody34)
Bought the starter motor on Ebay 47 Euro new. The pump from parts4 engines ca. 40 Euro´s.

 

[Muddywelly]

Any help please, as I'm mystified.

I've recently acquired a boat with a 36yr old Volvo Penta 2003 and I'm finding accurate control of revs almost impossible.
I've eliminated control levers and cables as causes by temporarily detaching them and operating the throttle directly by using the arm on the engine.

There is no slack/play in the arm and it moves smoothly with only modest force. Pulling the arm evenly increases revs from idle, 750rpm, anywhere up to 1000rpm, but at that point, the most microscopic movement of the arm lifts the revs which just keep on rising to 1400rpm. To put it differently, when increasing revs, it is impossible to select a rev amount between 1020 and 1390rpm. From 1400rpm upwards the revs once again rise evenly and will remain at whatever level is required.

Going down through the revs is a little better, but there is another 'dead spot' where the revs won't sit between about 1250 and 1000rpm.

Any thoughts or suggestions would be greatly appreciated.

I am the original poster with a follow-up of progress made. Just to remind you, my question concerned my Volvo Penta 2003, although the same issue could equally affect the 2002.

The engine revs didn't respond smoothly to smoothly increasing (or decreasing) throttle lever movements, there being a 'dead spot' between about 1000rpm and 1400rpm.

Engine revs would rise evenly between tickover (850rpm) and 1000rpm and then jump straight up to 1400rpm, from there upwards the rise in revs was once again predictably smooth. It was a similar story coming down through the revs, with a similar 'dead spot'.

I emptied and cleaned the fuel tank, replaced all fuel filters, thoroughly bled and re-bled the fuel supply, had the injector pumps (X3) and the injectors serviced and replaced the Morse cables, but all to no avail.

My suspicion was always the governor, but being awkward to get at on my Westerly Konsort Duo without removing the engine, I had clung onto the hope that the problem was elsewhere.

On this engine, the governor with its little weights is partially visible through the oil filler hole. A boroscope bought cheaply from a much used internet auction site revealed nothing, but it did prove invaluable for inspecting the inside of the fuel tank and for checking anodes whilst still afloat and for many other things.

The governor has moving weights, a sliding collar, levers and springs and it pushes a fuel rack rod which remotely operates levers on the injector pumps, adjusting the dose of fuel supplied. Any of these parts could be affected by friction or 'gumming up' producing a lurching instead of a smooth movement and therefore the symptoms exhibited by the engine.

Not being able or inclined to dismantle the governor, I removed the oil filler cap and with an aerosol can of PlusGas I sprayed the mechanism liberally, cranking the engine manually with the starter handle to ensure that all parts were steeped in the solvent. I left the engine to sit for a few days to give any gum time to soften and dissolve then started the engine.

There was an immediate improvement, with the dead spot much reduced. The next step was to work the moving parts by repeatedly increasing and decreasing the engine revs to further break down any stickyness. After just a few minutes and to my delight and relief, the dead spot that had troubled the boat's former owner for at least 6 years had vanished.

The Volvo 2000 series are very simple engines and so are easily understood and fairly ' bullet proof'. They were commonly fitted in their day and there are a lot of them about. I'm sure there are some bad ones, but it's those that are written about, not the thousands that still give reliable service.

A tip for winter starting, since there are no glow plugs, is to use a cordless hot air gun fired into the air intake whilst operating the starter motor. Makita don't make one for their 18v range, but there is an inexpensive Chinese one that uses standard Makita 18v batteries, that squirts out air at 500⁰C which helps A LOT!

In conclusion, don't be put off of buying a boat just because it has an elderly Volvo engine, but perhaps get it checked over first if you have any concerns.

 

[[70521]]

A tip for winter starting, since there are no glow plugs, is to use a cordless hot air gun fired into the air intake whilst operating the starter motor. Makita don't make one for their 18v range, but there is an inexpensive Chinese one that uses standard Makita 18v batteries, that squirts out air at 500⁰C which helps A LOT!

Good to hear that you have fixed the issue.

I've never had an issue starting my VP2002, are you aware of the cold start method as set out in the manual?

 

[Muddywelly]

Good to hear that you have fixed the issue.

I've never had an issue starting my VP2002, are you aware of the cold start method as set out in the manual?

Thanks Sandy

Yes, I do use the cold start procedure to which you refer and the engine has never failed to start, but is sometimes a little sluggish if it's very cold. To have a supply of 500⁰C air available at the flick of a switch does make life easier for the starter battery. I already had Makita batteries for my cordless drill, angle grinder etc, so for £40 or so a cordless hot air gun was a great substitute for glow plugs.

 

[Bilgediver]

Any help please, as I'm mystified.
Any thoughts or suggestions would be greatly appreciated.

There seems to have been a rash of simnilar problems recently and in one case the clue was in a picture but not commented on. It showed a severely distorted governor spring. .

It could just be gummed up parts in the governor and or the fuel pump rack which is not uncommon however I suspect it is a case of the governor springs having deformed with age which brings slackness into the system.

To help matters it might be worth giving the engine oil system a good flush and carefully removing the fuel pumps and checking forsticking racks. These can easily be freed by washing in diesel/ lube oil mixture. Be very carefull when removing the pumps not to lose the wee brass collet on the pump rack pin, if there is one fitted. Be just as as carefull when replacing the fuel pumps to ensure that the fuel pump rack pin engages with the governor lever fork. There have been cases on the forum recently when the owners had no contriol of their engines after tinkering with the pumps as the governor lever was disconnected and though it could push the fuel deliver to max it could not pull it back to min. .

New springs may not be available so be carefull not to further deform the governor springs.

The governors in most of the older small Volvo engines have a similar mode of operation so the same methods can be used to sort them all,

 

[Muddywelly]

Thanks Bilgediver for your input.

I did have my injector pumps out and back successfully and the protruding pins did move freely as did the fuel rack into which they slot. I didn't notice a collet, so I hope there weren't any!

Do you remember which spring was deformed? Was it one of the ones that draw the weights back to the centre, or one of the two that create a balance between the throttle demand and the governor, 21 or 25 in the picture?

 

[Muddywelly]

My spring labelled 21 in the diagram and two of the governor weights all as visible through the oil filler hole.

 

[Bilgediver]

I am the original poster with a follow-up of progress made. Just to remind you, my question concerned my Volvo Penta 2003, although the same issue could equally affect the 2002.

The engine revs didn't respond smoothly to smoothly increasing (or decreasing) throttle lever movements, there being a 'dead spot' between about 1000rpm and 1400rpm.

Engine revs would rise evenly between tickover (850rpm) and 1000rpm and then jump straight up to 1400rpm, from there upwards the rise in revs was once again predictably smooth. It was a similar story coming down through the revs, with a similar 'dead spot'.


Not being able or inclined to dismantle the governor, I removed the oil filler cap and with an aerosol can of PlusGas I sprayed the mechanism liberally, cranking the engine manually with the starter handle to ensure that all parts were steeped in the solvent. I left the engine to sit for a few days to give any gum time to soften and dissolve then started the engine.

There was an immediate improvement, with the dead spot much reduced. The next step was to work the moving parts by repeatedly increasing and decreasing the engine revs to further break down any stickyness. After just a few minutes and to my delight and relief, the dead spot that had troubled the boat's former owner for at least 6 years had vanished.


A tip for winter starting, since there are no glow plugs, is to use a cordless hot air gun fired into the air intake whilst operating the starter motor. Makita don't make one for their 18v range, but there is an inexpensive Chinese one that uses standard Makita 18v batteries, that squirts out air at 500⁰C which helps A LOT!

In conclusion, don't be put off of buying a boat just because it has an elderly Volvo engine, but perhaps get it checked over first if you have any concerns.

This is the best thing you could have done. Sliding sleeves and fuel pump racks do sometimes gum up. This happens on many engines and if any signs of this returning then I would recomend removing the fuel pumps and washing then in paraffin or diesel. with the help of a paint prush to work the oil into the rack area. be careful to put each pump and its associated ships back where it came from as the shim packs affect the injection timing so must not be mixed.

Do you use the correct 2000 series starting procedure when the engine is cold.

Put the throttle to at least half speed.

Pull the stop handle the full travel and return it to run position ( A click should be heard if head placed near the engine.)

Start the engine and set throttle to idle.

Should not require the hot air gun!