1991 lt-4wdM Gas entering lower end mixing with oil (4 stroke)

[countrylivin]

I am working on my buddy's suzuki quadrunner, and after replacing the ignition coil, cleaning out the carburetor, and basically patching almost every peice of plastic on the bike, I found that the lower end of the engine was FULL of gasoline, and the remaining oil had mixed with it. When I opened up the oil fill port near the rear axle gas/oil mix POURED out. I have since changed the oil and filter, and it runs pretty good now, my question is, what caused that? and how do I prevent this in the future? *note I have a carb rebuild kit coming via snail mail from ebay. is that all its gonna need to prevent this in the future?
I have heard rumors of possible vacuum/vent tubes tied together from the factory. is that the issue? thanks!

[countrylivin]

well the carb kit worked, but also found out that this @#$% bike has a vacuum powered fuel pump. It was full of old varnish and gum. after cleaning that out, It started and ran beautifully, but I am still concerned with the fuel leaking into the lower end again does ANYONE out there have any suggestions PLEASE?

[countrylivin]

well it seems to be doing okay, made it through deer season and the abuse that goes with that, just hoping it doesent happen again...

[amcf18]

Normally I would be thinking of a leaking float needle valve, or the fuel level being to high, due to the float tab being bent, or a leaking float.. On my 88 250 there is an overflow tube with a hose under the carb. It should be wet there if things are off... That's all I can think of right now..

[countrylivin]

it seems okay now, Over a month and all good...