Volvo Penta 2003 Cold Start fuel enrich schematics

[GlobalGaz]

Originally Posted by DougR

As far as I know, there was never a schematic produced which dealt with the cold start mechanism on the 2000 series engines. The only thing you can do is check the parts book. Because the throttle and stop lever shafts are supported by the housing cover, it is difficult it see what is actually happening in there without cutting a large hole in the cover....( and that has been done before).

Basically the position of the fuel rack or control rod is controlled by the governor linkage and spring pressure applied by the throttle cable. At full throttle the linkage comes up against the max throttle stop, but when the the cold start is engaged, the stop is moved aside and that allows the linkage to move further than normal. This allows more fuel than normal to be injected, and if I recall correctly it also retards the injection timing so that injection occurs closer to TDC.

You can tell if your cold start mechanism is working by trying the following:
--ENGINE OFF--
Remove the 30 mm hex head plug on the rear surface of the block just to the rear of the last injection pump. Take care not to loose the washer under the plug. When this plug is removed you will see the aft end of the injection pump rack/control rod. With the throttle at idle, activate the stop lever, and the end of the rack will move aft and protrude about 4 mm past the surface of the block. Releasing the stop lever will allow the rack to move back into the block and it should reside about 4 or 5 mm ahead of the block surface. Now, put the throttle at its maximum RPM position and hold it there and then pull the stop lever all the way out and then push it back in again. When you do this stop lever movement, the fuel rack should move forward from its normal position until it is about 10 -12 mm ahead of the block surface. This is the cold start position.

If you get movements similar to these, your cold start is functioning correctly. You might find it easier to disconnect the throttle and stop cables from their attachment points on the engine in order to make it easier for one person to manipulate things and get full travel of the levers.

If you need a PDF of the parts book page, send me a PM and I will send it to you.

DougR

Thanks Doug, this is the best bit of information I have found on the Cold Start settings. I have actually got a rebuilt engine to go in my boat to fix the cold start problem when maybe this was all I needed

[TimWhit]

Originally Posted by GlobalGaz

Thanks Doug, this is the best bit of information I have found on the Cold Start settings. I have actually got a rebuilt engine to go in my boat to fix the cold start problem when maybe this was all I needed

I should like to add my thanks to Doug for the excellent info which helped me to solve a slightly different problem… Cold start worked fine but as soon as I put into gear, no power. Also when engine warm, I still needed to use the cold start procedure.
A key piece of diagnostic was to start the engine IN gear having initiated the cold start. POW! Immediate power to the prop which nearly pulled the boat off her mooring.
This led to the conclusion of fuel starvation which, having eliminated all the usual culprits (diesel bug, blocked filter, lift pump, etc), I eventually summoned up the courage to open the throttle control cover, carefully detach the spring (per workshop manual) and examine the insides. Photo attached using a mirror because of lack of space. Having seen how it’s all meant to work, I discovered that the nipple (labelled 2 in the manual disassembly, 4 in reassembly and item 22 in the parts list - all attached) had worked itself loose over the last thirty years by about 1.5 revolutions corresponding to about 1-2 mm of lateral movement- enough to mess up the fuel input. After tightening by hand (“Note! Do not use any tools”) and reassembling… bingo! Problem solved. Luckily, I discovered the problem before messing with the adjustments that are preset by Volvo Penta and in this case would not have been sufficient to resolve (see last pic).
Attached are some useful links that may or may not last…

https://www.volvopenta.com/shop/0/pa...tions/54143686
https://www.volvopenta.com/shop/0/pa...tions/54143727
https://www.volvopenta.com/shop/0/pa...tions/54143712
https://www.volvopenta.com/shop/0/pa...tions/54143713

https://www.marinedieselbasics.com/w...hop-Manual.pdf

https://ab-marineservice.com/wp-cont...SHOPMANUAL.pdf

Incidentally the cold start mechanism is quite a simple once revealed. The tab (part 8 of the regulator diag) is rotated away from the nipple (22) by the stop lever allowing the nipple to move further forward providing more fuel.

Hopefully that’s another 30 years for this engine which is at 5700 hrs so far…