I have an oil leak somewhere on this motor. It has the oil tank under the cowling, and when in the up postion using the transom saver there is some oil that must leak out and accumulates in the splash well of the boat. Has anyone had this trouble before ? I am trying to see if this could be a simple repair that I could do myself. I have taken the cover off but do not see anything dripping. I thought maybe this is something that is common and I would start by asking on this website. I think some boat mechanic types review this site frequently. Maybe this much of an oil leak is normal ? How can you tell if the automatic oiler is working? I have always done premix in my outboards before this. Any advise would be great.. thanks in advance..

I am trying to avoid a costly repair that could be a simple fix. I do not know anywhere to take it but if it helps i am in the western suburbs of Chicago IL.

I have a 2002 90HP Classic and have the same problem. I still haven't found where it comes from as I see no oil on the tank itself. Just all over the inside of thecowling, which leaks into the splash well. If you don't fill the reservoir all the way, it doesn't leak. I assume because of this, it is in the cap. I have tried replacing the orings on it, but I still get the oil. I rarely go anywhere where I would need the whole oil tank filled as I mainly fish one day then the boat sits a while. If I do fish multiple days, the boat stays docked somewhere. It is an annoying problem, but I haven't found the soultion yet.

I have the same problem on my 200 Hp Merc. Got it narrowed down to maybe a gasket. Check all your oil injection lines. My first leak was a small pin-hole in one. If you clean everything up with brake cleaner or something similar it's alot easier to find. Just a couple suggestions for you. One mechanic said to spray everything with a powder like dr scholls foot spray. Didnt try that as my motor has no athletes foot. But all kidding aside it might help to find the leak.
Good Luck

If these are carburated motors,it's pretty normal. Same always happened to my 90hp Merc,when tilted up for
long periods. I never found any leak. With the way the oil injection system works on Mercs,I am pretty sure
that the fuel in the carbs already has oil in it. When tilted for long periods,eventually just spills out of the carbs,into the front of the bellypan,and drips into the boat splashwell. A pain,to keep clean but nothing really
wrong.

Take off the cowling, inspect everything as best you can to make sure nothing else is leaking,but if you find nothing I wouldn't worry about it. But periodically clean up the bellypan so it does not build up to much
and attract dirt.

...Followup....(it's been a while since I had that motor)...
Take off the cowling. Unscrew the airbox cover on the carb assembly. You will probably find it wet with fuel and oil. As I recall it eventually migrates out of there when tilted.

For a fix to the oil leak on a Mercury outboard - go to www.ebay.com (http://www.ebay.com) and type in "Merc BUDDY" for a solution to this problem. You can also go to www.robbco-llc.com (http://www.robbco-llc.com) for more info on this solution. Not only fix the oil leak - but also provides for a back up in case you loose your cap & dip stick in the water.

I have had this problem since purchasing the 90 hp merc since 1992. I must admit, this has been the only problem with the motor. Thats right 20 years old. The problems....incomplete combustion of oil and gas......according to the dealer 18 years ago. Its the only flaw associated with the engine. Although today I noticed a bolt in the engine cover...