Briggs 16hp blowing oil

[EGL&L]

I have a 16 hp Briggs ELS 465 with 660 hours, on a Quick 36 mower. First use this season, smoked heavily on side hill operation (has happened in past after oil change). Drained some oil out on site, smoking stopped, but now it's blowin ALOT of oil out through the fuel pump (assume its the crankcase vent).
Does not blow any oil sitting in idle stationary position, only when in use and also on level ground.
PLEASE OFFER SUGGESTIONS!
Thanks,
Bob

[EGL&L]

Anyone?
Not sure what would cause this pressure that would create oil blowing through the fill tube vent/overflow, even occurs when oil is low.
What would happen if I block the overflow/vent tube?

[viper00085]

basically other than like you mentioned you checked, being over full on oil or having gas saturated oil (thin) its prolly not a simple issue/fix. It could be something with the breather system, but its rare to see an issue with them.

best thing to do is run compression and a leakdown check and find where the blowby is coming from causing the excessive crankcase pressure. The leakdown test should narrow it down wether its valves, rings, head gasket, etc and then start tearing it down to see the extent of the damage/problem.

One problem I have seen on the ELS series is a lot of dirt ingestion failures. If you dont stay on top of those filters, the engines get dusted and killed quickly. we have even seen them with carb throttle and choke shafts worn out and moving in the carb body substantial causing un-filtered air being sucked in right past the shafts and killing the motor from dirt ingestion.

[EGL&L]

Thanks Viper.
Is there a special tool that I need to take the flywheel off? I'd like to remove the breather cover to see if it's blocked, causing the excessive pressure to blow out through the overfill tube. However, part of the cover sits beneath the flywheel.
Thanks,
Bob