Volvo Penta MD-1 will not rev up or down but does run

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cloudsrule9

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So i have a old volvo penta MD-1 in a mirror offshore, which currently runs but only at one speed. It starts and then runs at idle but does not respond to change in the throttle. The only way to stop it is to open the decompression value which is used to aid hand starting. The throttle moves freely, (it was stuck for a while but after cleaning the cable it works well). Any ideas?

I'm guessing some part of the governor is stuck so i removed the inspection plate and sprayed the governor with oil in and effort to free up whatever is stuck but this had no effect on the engine. Am i looking in the right area or is there something else i should investigate? At first i thought it could be a blocked injector but this doesn't explain why it will not slow down. The usual way of stopping the engine is to pull back on the throttle until the engine dies. Any input greatly appreciated as i can currently only motor at about 1 knot which against the tide in Morecambe bay just mean i go backwards.

Rob
 
I too am blessed with an MD1 in a mirror offshore. I am under the impression that it is the pump that controls revs. These are pretty simple items but not DIY maintainable so I would be inclined to take the complete unit off and get it to a diesel expert (preferably a tractor one, not a boat one). Might be worth having the injector overhauled at the same time.
Have you got a workshop manual? I've got it in digital form if you need it.
 
It could be the pump. I have the original "Workshop manual". The manual does suggest that the fuel is controlled by the adjusting the "injection pump rack" so this could be the problem. Ill see if i can find anywhere local the reasonably priced to have a look at it. The boat is based in Morecambe and i live just down the road in Lancaster.

Cheers,

Rob
 
If you are very lucky it could be no more than a stuck rack on the fuel pump. This can be freed in place but on the MD 1 it is just as easy to remove it. Be very carefull lifting the pump off as where it connects to the governor linkage is a wee slipper shoe on a pin and this can be easily lost in the engine if rough handling causes it to fall off. Be very careful re assembling.

Soak around the rack area with diesel oil or even 3 in 1 oil and work it free by sliding to and fro. It is probably just gummed up. The rack is the thing the pin is attached to an slides to and fro.
 
Might try to free the rack (assuming it is stuck) in place to start with, as access to the engine is very tight so would probably have to remove the whole engine to get to the pump out. Any tips on this?
 
Certainly worth trying to free the rack via the access hole . I am surprised you cannot gat at the injector pump. What boat is it?
 
Boat type stated in original post. Access to the engine is very tight. I've never taken the injector pump off mine but it would be difficult.
 
cloudsrule9 said:
Might try to free the rack (assuming it is stuck) in place to start with, as access to the engine is very tight so would probably have to remove the whole engine to get to the pump out. Any tips on this?
Click to expand...

Once you have freed the rack which might just be gummy and have put it back in place check that when you move the speed lever from slow to fast and back again you can see the rack moving by looking through the access hole in the engine. If still not working then maybe a broken regulator spring.
 
Thanks for the advice. I was at a wedding the weekend so no time for the boat, but i hope to get down this week/next weekend so ill report back. Unfortunately the mirror offshore was not designed with access to the engine in mind.
 
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