15 hp Honda 4 str Oil Leak

"Hey I was handed a 15hp 4 str

"Hey I was handed a 15hp 4 stroke OB with I think a pretty heavy duty problem. I'm not sure what exactly is wrong but symtoms include oil leaking out of cooling water intake, through prop exhaust, and through the pressure relief exhaust (which ends up leaving a black stain below it). The motor also needs to be refilled with motor oil every 5-7 hours of running. I know that there may be a gear-case seal failure but I havent checked yet but I dont think that would cause oil to come out of the exhaust. I will take a closer look at the engine but I'm interested in any leads as what to look for. Thanks"

"Nicholas, may be a seal leak

"Nicholas, may be a seal leak on the crankshaft, and also if it is 5 to 10 yeras old they do corrode thru the alloy crankcase into the exhaust area, both require a power-head removal to check, Ray"

"In 1998 Honda built a few 15

"In 1998 Honda built a few 15 HP outboards that were sort of transitional in design. These were built with a defective crank case vent. I had one. The crank case on mine was vented via a small rubber hose to the carb intake. One problem; Honda forgot to drill out or mold the little plastic nipple on the the plastic carb intake. In other words, the crank case vent hose dead-ended at the carb intake. As the engine ages there is a bit more piston blow-by that increases crank case pressure which either blows the hose or if you are unlucky, which happened in my case, blows the main seals, gaskets etc...... Honda knew it was a problem but took their chances that you would not have problems. Bastards!! No recall. Nothing! The solution on mine was to drill out the carb intake so the crank would be vented properly. Check yours. Honda agreed to pay the bill for everything in my case. Screw 'em. I bought a Yamaha."

Correction: It was a late 1997

Correction: It was a late 1997 15 HP Honda that had the problem (Not 1998).