Missing Flappers and performance issues

[shaps1001]

Hi All. I have a 1993 OMC Cobra 5.0 that will only get to 3500ish rpm at WOT. After checking pretty much I everything else, I read about problem of broken flappers blocking the exhaust flow. I had actually seen the bare in pins in the Y pipe when I changed the risers but I didn't realize that there was supposed to be a flapper there.

I took it apart again but I couldn't see the missing flappers from the top. The outdrive is due for service anyway so I plan to pull it to look for the flappers and replace the bellows/gimbal bearing.

My question is where in the outdrive do the flappers usually end up? Can they can make it past the exhaust bellows? If so will I have to open up the outdrive? Where else do I need to look?

 

[Randy J]

Re: Missing Flappers and performance issues

underneath the exhaust water hose with the cut outs they can go all way into the foot and usually melt & jam up against the shift rod can be fished out with thru the tube with long nose needle pliars

 

[shaps1001]

Re: Missing Flappers and performance issues

Does that mean I will need to open the outdrive case?

 

[Randy J]

Re: Missing Flappers and performance issues

nope lay under boat and look up where very bottom hose is will see slits gently take a big flat blade screw driver and a real good work light and just gently look inside of hose toward the foot where it goes more n likely will see the old flappers, most of time therye a melted mess will have to have the drive raised all the way up tho and be sure to have it secured for safety, i put a rope on it and tied off to ski hook at back of boat, i know it dont come down on its own etc but id rather be safe than hurt lolo

 

[shaps1001]

Re: Missing Flappers and performance issues

Flappers were definitely my problem. One was completely blocking the exhaust bellows and the other was in the outdrive.

 

[shaps1001]

Re: Missing Flappers and performance issues

I have another question. Since I have the outdrive off I'm going to replace the gimbal bearing. Can I use a flat style bearing driver like these? http://www.amazon.com/OTC-4507-Bearing-Race-Driver/dp/B000O824Y8

I rented a similar set from Autozone for free, but it seems like everyone else is driving the bearing from the outer race only.