Gasoline in Oil - Yamaha f115

Hello all...wondering if you might give me some ideas on how to fix a problem with my Yamaha 4-stroke 115.

The problem started when I noticed my engine bogging down when trying to run at higher RPMS. I figured it was some sort of fuel system problem since they guy I bought from didn't use the engine that much. At any rate I ran several bottles of Techron through the system and that didn't help much. In fact it seemed to make the problem worse freeing up lots of crud in the system. I ended up taking the high pressure tank apart and cleaning all the varnish out then testing the engine. After the testi I checked the oil level and it was overflowing. This happend after only running the engine for 20 minutes or so. I drained the oil and it was obvious it was very diluted with gas. Refilled it and tried again. I can now get 4400 rpms (should be able to get 5500), but after running the engine the oil tank was filled with gas once again (only ran it 30 minutes). At any rate I have no idea what the problem may be, but I'm running out of time to get it fixed before a week long boating trip. Any ideas what may be going on? I love to take it to a dealer, but everyone has a couple week wait to get in and I just don't have that much time.

At any rate, thanks for your help.
LF

[boats.net]

Check fuel pump for ruptured diaphram leaking gas into crancase. Check to see if Vapor tank is overflowing, could have float valve not seating.

Thanks. Will check it out.

Just a quick recap for those who are interested. The bogging down of the engine was most likely caused by varnish build up in the fuel system and got worse when I used techron to try and clean it out. The solution was to pull and clean the injectors plus pull and clean out the high pressure/VST tank. Also checked the float and shut off valve in the top of the tank while it was apart. Lots of junk in the tank plus injectors were clogged.

The gas in the oil problem was most likely caused by a failed diaphram in the fuel pump located on the back of the engine. Due to the volume of gas in the oil and the short time for it to build up this seems like the most logical conclusion. I did however change the thermostat for good measure. I'm not certain, but it seems likely that the diaphram failed after being in contact with the techron in the system. Not that techron is that potent, but the diaphram was old and tired (7 years) and ready to give up the ghost.

Thanks for the help everyone.