Yanmar 3GM30F Gear Case cover removal

[dmksails]

There is a problem with the injection pump on my 3GM30F. Either the rack is frozen or the linkage is frozen. I can't move the rack pin to align it with the slot as needed to remover the pump. The manual I'm using says to remove the pump before removing the case cover. Has anyone removed the case while the pump was still installed?

[Compass790]

I'm guessing here but maybe they say to remove injection pump before removing case as the plunger rollers get hung up on the cam lobes? I'd try spraying the fuel rack & linkages with penetrating oil to see if you can free it.
Hope you get a reply from someone who has done it & then you will know as its just my speculation.

[Wotname]

Going from unreliable memory here.

The injector pump should lift up without removing any covers.
You must remove the gear case side cover (red arrow) when refitting to ensure the rack engages with the governor lever 2 slot.

[RaymondR]

Originally Posted by Wotname

Going from unreliable memory here.

The injector pump should lift up without removing any covers.
You must remove the gear case side cover (red arrow) when refitting to ensure the rack engages with the governor lever 2 slot.

Also my recollection from a similar deteriorated memory. Also vaguely recollect that there is a shim under the pump related to timing.

[Wotname]

Originally Posted by RaymondR

Also my recollection from a similar deteriorated memory. Also vaguely recollect that there is a shim under the pump related to timing.

Shim memory is correct

[SVQuestOfPaget]

I was in your exact situation last July. The engine had sat for 11 years without anything done except to manually turn it every so often. While going through the engine to get it going again, I found the stop lever wouldn't operate, which led me to find the stuck fuel rack. The 3gm30 shuts off with the rack in full forward mode, and the diesel had turned to varnish in the meantime. No amount of penetrating oil appeared to help, and I disassembled the top of the fuel injection pump to no avail. The front of the rack locks the injector pump into the case cover.

Long story short, the only way to remove the pump was to unbolt the gear cover, which proved a lot easier than I thought it would be. It did require a gear puller for the belt pulley and removal of most of the front of the engine, but was not difficult. I used the same gear puller I have for my propeller. The engine rebuild manual available online in PDF form is super helpful!

What Compass790 said is also correct - the cam lobes will normally want to catch on the plunger roller, but having the injector pump loose will prevent it from catching as you pull the case cover off. Wotname is also right that there are shims under the pump that MUST go back the same way. Mine were fairly glued to the crank cover with grime.

Once removed, I could disassemble the pump from below and free up the rack. The fuel injector pump is a precision and complicated piece, so take care with disassembly - let a professional clean and put it back together if you're not 100% confident.

Reassembly was reverse order, but with new gaskets, torquing everything to spec - and the inspection cover needs to be off in order to line up the injector rack with the governor fork.

I have photos of the crank removal here: https://www.instagram.com/p/CRXm5aPL4W_/

And a few of the injector pump rebuild here: https://www.instagram.com/p/CRkKHMrLsNU/

I hope this helps! FWIW, the engine started up and ran beautifully shortly after finishing the work.
-Eric