Minimec pump rack

Nick · Post by **Nick** » Sun Oct 17, 2010 8:26 pm

On the super major engine im currently re-building, i suspect the fuel pump rack is stuck because the stop lever doesnt feel like it does anything. The pump does click though when the engine is turned over.
My question is, which bolts do i undo to get to the rack?
Any help will be greatly appreciated

Nick · Post by **Nick** » Mon Oct 18, 2010 8:50 pm

well i decided to take the side panel off the pump earlier, and found what i think to be the rack, its quite stiff to move but slowly got a bit easier. When i moved it back, the stop lever moved to the run position, so then i pulled the stop back, then forward and back and so-on. I didnt do it too much incase i messed something up, but in theory if i keep doing this should this free it? also should you be able to push the rack both ways on the stop lever or just off?
one for you brian i reckon

henk · Post by **henk** » Mon Oct 18, 2010 9:05 pm

Nick,

Don’t know if the stop device works the same as the old pump, but I think it works one way.
I recon its not easy to remove the stop unit.
Could be some grease and dirt that’s holding up the rack. Try some diesel to clean a bit and see what the rack does.

Nick · Post by **Nick** » Wed Oct 20, 2010 6:14 pm

i agree it looks difficult to get to the stop unit. when you bleed the system up, does the whole of the inside of the pump fill with diesel and are you supposed to put oil in it too?

henk · Post by **henk** » Wed Oct 20, 2010 7:38 pm

Nick,

I can say a lot about the old pump but not the minimec, but I dont think you need oil to grease it. It will use the diesel that leaks.

Nick · Post by **Nick** » Thu Oct 21, 2010 7:38 pm

well to me it looks like the pump is almost divided into two bits, but im not sure. Ive undone the oil filler plug and sprayed a bit of oil about and it got alot easier to move the rack.
Does the rack move when operating? If it does then i assume its sprung so it moves back when the stop lever is moved forward, so in theory when it moves on its own, it should work?
Ive never taken any sort of fuel pump apart before!

henk · Post by **henk** » Thu Oct 21, 2010 9:20 pm

Nick,

The rack is moving constantly when the engine runs. Therefore the rack has to go smoothly.

Post by **Brian** » Thu Oct 21, 2010 9:28 pm

Do not take it down any further! If you have got any microscopic dirt in there you could have already damaged it.

The Minimec has a mechanical governor in which has to be filled with engine oil, about 1/3rd of a pint. It should be changed every time you change the engine oil.

\the stop lever pulls the rack and moves the metering valves into the no delivery position. The rack is normally controlled by weights in the governor housing.

If the excess fuel button has been pressed in, it will not usually fly out and release the rack, untill the engine has started. The throttle has to be set at around half open for the button to latch.

It can stick and if this happens the engine will stop after a short run and will not start again. If the stop is pulled, this will sometimes release the rack but sometimes you have to physically pull the button out with pliers.

If the rack moves with a screw driver, leave it at that and try and start the engine. If it won't start, you should then take the pump to someone who has the proper tools and setting equipment. You can terminally damage the pump and your engine if you try to do it yourself.

Nick · Post by **Nick** » Fri Oct 22, 2010 8:01 am

dont worry brian, no dirt has got inside and im not planning to take it apart anymore than i have already. i will get on with the engine and try and start the engine, if it doesnt and i have to take the pump off, how do i make sure it goes back on timed correctly. do you have to mark the pulley?

Post by **Brian** » Fri Oct 22, 2010 5:06 pm

Just line up the mark with the indicator, on the top of the coupling. Make sure the bolt is below the drive shaft and line up 21 degrees on the flywheel through the window.