Evinrude (1993) 90hp VRO problems...Did I cause it?

[sctoney]

Bought used boat a few weeks ago. 1993 Evinrude 90hp VE90LETS on a 19' Four Winns. Ran fine when I tried it out. Got it home and was checking it out, noticed o-ring under oil fill cap broken (it's a remote-fill on deck--tank is below deck, fuel tank is also below the floorboard). I put on an o-ring I had that was much thicker, thinking that it would be okay. Went to the lake 2 weeks later, motor was hard to start and smoked badly for 5+ minutes after I finally got it running. Took the o-ring off the cap, thinking that it might be blocking a vent or something like that. Ran fine the rest of the day. Was going to go to the lake yesterday decided to start motor before we left. Motor would not fire. Put in a new set of Autolite 2634 plugs (all the parts store had), and it finally started, but ran very rough and smoked badly. Cancelled trip to lake. Looked through many forums and think the fuel pump isn't working. Took the VRO off and opened it up. Diaphragms look good....no cracks or holes. One forum said the fuel piston valve (the big flat rubber washer #10 ) sometimes will swell up and be the problem. Mine looks good, but it measures 1 13/16". The forum said it should be about the size of a half dollar, which is 1.20". Does this sound correct?? Also, the fuel in the fuel filter is blue, so there is oil in it, but the tank only has raw gas in it. Is that normal for the oil to backflow into the filter when setting a couple of weeks n 90+ weather? I'm thinking of putting kits in the fuel pump and air motor. Do you think this will solve the problem?? Did the fat o-ring on the cap seal off the vent, causing the heat expansion to push oil into the carbs and the fuel filter?? Any other ideas?? THANKS for any help........ Stan

 

[Boobie]

Sounds like your oil tank built up pressure for not being vented. Get yourself a new oil cap as they had problems with some of them.