Volvo 2040 Rough Idle when Cold

[ben373]

My 2040 has approx 2200 hours and runs well when warmed up. However, when cold it idles roughly. Need to go to almost 1400 rpm to smooth out.

The motor starts easily and does not smoke. It is used regularly and the fuel seems good. Once warm the motor idles OK.

I have had the boat since 1500 hrs and it was like this but seem a little worse now.

It has a service history and all is OK. It would appear that the valve clearances have not been checked

Any ideas most appreciated


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[colemj]

By cold, do you mean cold temperatures, or just when it hasn't been started in a while?

Have the injectors ever been serviced? Poor injection would cause incomplete burning when cold and rough idle. You usually see white/gray smoke in the exhaust from this, or a bit of unburned fuel on the water right after starting.

Mark

[Ex-Calif]

I think you know the answer. Before going down the path of 100 guesses from the internet why not do a "full" servicing of the engine including injectors and valve clearances. If you have big concerns maybe a compression check as well.

In about 30 seconds you are gonna get every bit of advice from clean the fuel tank, add racor filters, bleed the system, repaint the hull etc, etc, etc,...

[h the boat]

Very common problem on all the Volvo engines of this series. First step, check and adjust Valve clearance when cold. Not warm as most recommend.. If their is no colour to exhaust, it is unlikely to be injector, (But could be a poor spray pattern when cold. A second common fault, is poor valve stem fitting clearance, causing bad seating of the valve whilst cold, which clears up as soon as their is sufficient oil around the valve stem to produce a balanced centering.Unfortunately this is a head off job, where the labour content is great but the cost of the items is minimal.. Rgds h the boat.

[ben373]

Thanks so much for the advice. I will do the valve clearances cold and hopefully that will help. Nice to hear it can be a common fault. Not sure about spending money on removing the head. When I have done this in the past on motors it would have been better to get a new motor. Thanks again for the input.

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[h the boat]

Hi again Ben 373, If you find that you may need to remove and service the head, seek out a recommended individual mechanic, ( beware of Volvo dealers). It is not that difficult to get good access to the engine on your vessel, although you may have to unscrew a few panels. Or alternatively remove the unit complete from the boat and service ashore. This series of engines were made by the Perkins group for Volvo. The engine is a basically well designed unit where repair and servicing has been taken into account in its original conception. to remove a cylinder head (if the engine is in a workshop on a bench) rarely takes more than HALF AN HOUR. The only tools required are a socket set, fitted with hexagon drives or possibly on some versions Torxs drive, a few open ended spanners and a screwdriver. Which any competent mechanic will have.. To remove valves for inspection is exactly the same procedure as for earlier automobile engines, (no overhead cam shaft). If as I strongly suspect, it is a problem with valves guides, Your new found mechanic will know of a local machine shop, where he can have the valve stems measured for excess wear, and will have a standard valve which they can use to check the wear within a guide.. to replace a valve guide, they are pressed in or out with a hydraulic machine, a normal job for them. Most times the guide is correct size when fitted. If the valve or valve's stems are worn beyond an acceptable limit, replace them as well not forgetting to reseat the valves.. As a guide, the total cost for all the parts, 6 valves and 6 guides (in Europe) should not be more than £100.oo, plus or minus any premium for Australia, assuming you change them all which may not be required. The labour cost, should not be more than 4 hours, including machining and re assembly, although it will take longer than that because it cant all be done in one go.. let me know how you get on. Rgds. h the boat.