Volvo MD17D Cold Start fitting-what does it do?

[Kurrawong_Kid]

As I have replaced the injection pump, following a saga involving the removal of the engine (as mentioned in earlier posts) I have noticed that the "cold start"pin is drooping because the seal in the cold start fitting is damaged. I have put a couple of cable ties around the pin to help make contact with the operating arm and allow the correct adjustment to be made. However a cable, which also stops the engine, attaches to a seperate fitting which also has a pin on it and activates the operating arm. Does anyone know if the" cold start"fitting actually does anything or is it just redundant from earlier models without remote controls? I attach a sketch which may make it a little clearer. Further clarification may be found on the marine parsts europe exploded views.

 

[Jcorstorphine]

Hi, I can only make a comment on my old MD2B which was two cylinder version of your engine. My engine had a cold start and if I did not deploy it, there was little chance of the engine starting even in the middle of summer (engine was quite worn) The device on my engine was a brass button which one pressed and it would stay depressed until the engine started when it would be released. My understanding was that it opened the fuel rack 100% to inject extra fuel to assist the engine to start. I have looked on the Marine Parts Europe and the unit shown there is totally different. The only schematic i can find is this one which shows a solenoid operated device in lieu of the brass button but I am sure its serves the same function.

Volvo Penta Exploded view / schematic Cold Start Control - MarinePartsEurope.com

 

[VicS]

Hi, I can only make a comment on my old MD2B which was two cylinder version of your engine. My engine had a cold start and if I did not deploy it, there was little chance of the engine starting even in the middle of summer (engine was quite worn) The device on my engine was a brass button which one pressed and it would stay depressed until the engine started when it would be released. My understanding was that it opened the fuel rack 100% to inject extra fuel to assist the engine to start. I have looked on the Marine Parts Europe and the unit shown there is totally different. The only schematic i can find is this one which shows a solenoid operated device in lieu of the brass button but I am sure its serves the same function.

Volvo Penta Exploded view / schematic Cold Start Control - MarinePartsEurope.com

The diagram at Marine Parts is of the remote remote operation accessory for the brass button , and a solenoid alternative.

According to the owners manual the MD17 engines had an automatic cold start device ... I've no idea how that worked.

 

[Anthonyexmouth]

I'm interested to find out this too, my MD17d cold start button is missing/snapped off (before I bought the boat) and if left for a few days it is hard to start. once running it's a little smokey but sounds lovely. I'd be interested if anyone knows how easy it would be to fix the snapped button and if it's worth doing/would help my starting problem.

If anyone with a functioning MD17d cold start could post a picture of it that would be appreciated, looking at the drawings doesn't compare to a picture. all I have is a hole where the button was, no little levers or pins around it.

 

[Kurrawong_Kid]

Thanks for all your replies. I, too, can’t work out what the mechanism does. I think I’m going to try to remove it and see if I can source replacement springs. I first thought it was the seal that was broken but I can feel a crunched spring so now think that is the trouble. But is it a thermostatic spring?

 

[Bilgediver]

Thanks for all your replies. I, too, can’t work out what the mechanism does. I think I’m going to try to remove it and see if I can source replacement springs. I first thought it was the seal that was broken but I can feel a crunched spring so now think that is the trouble. But is it a thermostatic spring?

The cold start on the MD2B etc when pressed removed a spacer from the end of the fuel pump rack which allowed the pump rack to travel a further few mm aft to give increased fuel deliver. As soon as the engine picks up and the governor shifts the rack to the control position (forward) the spacer pops back up into position. Beyond the spacer is the governor setting screw for adjusting for acceleration and maximum fuel delivery and if this is set incorrectly the engine either picks up revs too slowly or causes the engine to smoke due to overfuelling if set to the other extreme.

The MD 17 seems to have a more complex cold start where a hydraulic piston does the job. I am not sure that it has a spring loaded button as well?

 

[VicS]

The cold start on the MD2B etc when pressed removed a spacer from the end of the fuel pump rack which allowed the pump rack to travel a further few mm aft to give increased fuel deliver. As soon as the engine picks up and the governor shifts the rack to the control position (forward) the spacer pops back up into position. Beyond the spacer is the governor setting screw for adjusting for acceleration and maximum fuel delivery and if this is set incorrectly the engine either picks up revs too slowly or causes the engine to smoke due to overfuelling if set to the other extreme.

The MD 17 seems to have a more complex cold start where a hydraulic piston does the job. I am not sure that it has a spring loaded button as well?

According to the owners manual MD17 engines have an automatic cold start device

 

[Bilgediver]

According to the owners manual MD17 engines have an automatic cold start device

View attachment 105096

Yes Vic it looks like the MD11 has the same button as the earlier MD2B Type which on some installations had a wire pull system as an accessory . The MD 17 seems to be a different system and I am not sure that the hydraulic system operates a movable spacer at the end of the rack but achieves the excess fuelling in another way.