The seals all seem ok (fingers crossed)
It's the standard M180 2.2 petrol engine, but ours has a vacuum advance carb on it. It wasn't plumbed when we got it, but having added the vacuum line it makes a massive difference. Tricky to tune though (not my job)
We ended up with the military dizzy as well and tried that, yuk. It's much faster than stock and sounds awesome.
jim