While changing the oil the other day, I tried to put the drain plug back in. With a VERY moderate amount of torque, I noticed the plug would slip and get loose again. Finally, I took it out and noticed a strip of aluminum from the oil pan in the bolt’s threads. I’m guessing that the last folks I paid money to service the motor torqued the drain plug too much because I had to put all my weight on the wrench to get the plug out. Plus, the aluminum oil pan with with a stainless steel plug just seems like a bad design…
I called one place and they want to replace the whole oil pan and estimated about $1,300 for the repair. A second place I called seemed a little less sure that they could fix it at all.
Is there a better option? Can someone PM me a good reference on who could fix this without having to replace the whole oil pan? I’m hoping to get back on the water while these warm temps hold!!
I am not an outboard mechanic. However I did see a very inexpensive repair for your problem on an F150 Yamaha. When a buddy of mine stripped the threads on his oil pan he went into a major funk for several days. During this time he took his truck to one of those 15 minute oil change places. While there he asked them what do they do when the threads strip on an oil pan. They showed him a rubber plug that looks similar to a boat drain plus. It had a bolt in the center for tightening and looked to be very substantial. He ran the boat for at lest two years with that thing in the drain hole before he sold the boat.
As I said I am NOT a boat mechanic. That thing may blow out and kill your engine the first time out; or it could be a quick $20 fix.
Not a boat mechanic either, but I am an auto mechanic. Typically, in an aluminum pan (if room allows) we will drill the hole and tap it to accept the next size up oil plug. (i.e. if you have a m12x1.50 plug then drill with a 1/2 drill and tap with m14x1.50 tap.)
It works on cars 99% of the time. It may be a possibility that this could work, but there is always a chance it won’t.
I used a helicoil on a motocross bike one time before it worked great. As Chris said the oil on these should really be sucked out and I would be leary about using any shop that is not removing oil in this manner. This is definitely a design flaw by Yamaha. I changed my oil one time on my Yamaha F250 using the drain plug, after I saw how thin the aluminum was I vowed never to remove the plug again for this very reason. I purchased a oil change pump from Westmarine and it is a slower process but cleaner and you don’t have to worry about the plug.
Since everyone on here is always busting on Mercury I will throw this in here as well. Mercury is heads and shoulders above Yamaha on ease of service. My 115 four stroke has a port just below the cowling. Hook a 1/2 hose to the port, turn it a quarter turn and you empty all the oil in 10-seconds right into what ever container you want to direct it to. Hook a 3/8 hose to a port just below the oil filter and lossen filter, excess oil from filter is caught in a small catch that drains right into the hose. By the way the oil filter is mounted right there on the starboard side of the block and is accessible with a plain old filter wrench, no need for a filter cup, wobble, extension, miniature hands, and busted nuckles to get to it like my Yamaha. Mercury foot oil drains from a plug right behind the prop so when you pull the prop to grease the shaft you can pull the plug, no need to try to get up under the angled side of the foot like the Yamaha.
Like I said I own and have serviced both myself, Mercury takes 1/2 the time, no exaggeration. Just saying!
In the auto shop we prefer to replace the oil pan and move on, but I can vouch for the rubber plugs too.
When cash is an issue, those rubber plugs sure are cheap, fast, and effective. Never had a problem with one after we installed it.
They have a toggle bolt type core, and a wedge shaped rubber core. Shove the toggle bolt through the drain hole, torque it finger tight + 1 grunt. That is the route I would go until I had the cash/time to do it properly.