I bought an ms880 a while ago, my mate is repairing it, tried replacing parts in the oil pump but it didn't fix the issue, he reckons it's possibly the pipes or something deeper internally.
I originally suspected that the pressure from the engine was forcing out the oil.
It really does pump it...
Just picked up a Homelite xl -800. Its a runner, I brought it home put gas in it and fired it right up. However, I poured oil in the tank and goosed it up and no oil comes out the weep hole. This was one of the earlier 800's that has an auto oiler only. Its not even drilled for the manual pump...