"Adult Depends" Won't Work Here!

I know, I've always ranted and raved about the reliability of the good old Yamaha Four Strokes, but, they too will develop drips and leaks with age, just like us!  I recently experienced (not me, the motor!) such a leak, which was found one morning when I saw a few drops of oil on the driveway, right underneath the skeg of the big F150.  Further investigation revealed it was in fact motor oil and not oil from the leg, not a good thing, so I went to work to track it down.

Most of the four stroke outboards are pretty much the same in their construction, the big difference between it and a car motor is that they have what is called a "dry sump".  When you put oil into a conventional car motor it all runs down into the oil pan, which is totally exposed to the underside of the motor.  With outboards such as mine, when you add oil it runs down and into a oil pan, but the oil pan is seperated from the motor by the cowling and another plate, and goes into a oil pan there.  When the motor is running, the oil pump draws oil from this reservoir up to the top of the motor and then dumps it to various areas of the motor for lubrication and it all then just falls right back down into the oil reservoir and repeats this.  My Yamaha Turbo Nytro was a four stroke and it was the same thing except the oil resevoir was beside the motor rather than under it.  Back to the leak.

I took brake cleaner and blew the living bejesus out of the motor and leg area, to get any excess or hidden oil off of the motor and leg.  I dried off every orfice I could access and made sure there was no oil to be seen.  I then made sure the motor was topped up with oil and I hit the lake, to do some fishing of course!  When I got home I  did another inspection of the motor and low and behold the first drip of oil appeared on what I later discovered was in fact the oil pump for the motor.  I of course bought one of the few motors, that I know of, where the oil pump is actually at the bottom of the powerhead, not on the side of the motor like some are, and to fix it, the entire powerhead must be removed!  I personally don't have a problem with this, I've re and re'd many a truck and car motor in my time and tore them down so a mini version of that was not the worry, it was what else I may find when I did tear it down that worried me.   Up here in Canada getting the Royal Shaft everytime we buy something  is normal, especially if it has the word "Marine" stamped on it, I just knew this was going to be a costly adventure.  Guessing at what I might need, I ordered some parts through a Marine dealer down in Florida, had it shipped, free, to a address in Oroville, Washington, just across our border from Osoyoo's, at half the price!

So, I found that taking the powerhead off of anything is not really brain surgery, its putting it back together that requires a little more patience and expertise.   When you take the cover off it all looks so danged complicated and , if you were to get into the meat and potatoes of it, it is!  However, discard all those belts and hoses and strange black box thingy's, because they have nothing to do with taking the powerhead off.  In fact, after reading a decent factory manual, the only problem I had was finding what they called "8 narrow bolts" that helped to hold the top part to the bottom part.  As frustrating as it was, I did finally find these (photo), those 3 big ones on the bottom were the "missing" bolts.  From the description in the manual and from what I saw, I had no idea they were so big or extended so far below the cowling, they actually go up through the bottom of the oil reservoir! 

Anyways, after disconnecting stuff like fuel lines (photo), throttle hookups (photo) and various wiring harness's (photo) AND making sure you tag everything where it came from, the removal of the motor was easier than pulling hen's teeth, which I have no idea how to do.

I think the biggest challege for anyone to do this type of work is to have the proper tools and, the proper size workshop to do it in.  Luckily I 've always had the proper tools and when we built our house I made sure the shop had a nice high ceiling in it, because you have to have somewhere to yank that motor way up in the air to clear the cowling.  What I already had in my ceiling trusses were hooks that I installed to hang up my game, or to hang up my sled when working on it.  Each hook is just screwed into the wood truss but have a holding strength of about 250 lbs, how do I know?  I hung off of them when i put them in and no, I certainly don't weigh 250 lbs thank you very much!  I figured the motor to be a max of 300 lbs so by using all four hooks (photo), there should be enough strength to support the motor when lifted straight up.

I originally tried to use the winch on my ATV for the lifting but, what it did was pull sideways to much and didn't distribute the weight properly, and almost wound up pulling the hooks right out of the ceiling.  By using the block and tackle as seen in the previous picture it worked like a charm.  What you have to be careful of is that when you lift the motor up is that you lift it straight up, as the drive shaft is still stuck up into the crankshaft at this point.  If its crooked for any reason you could wind up actually bending the driveshaft, even though it is pretty scookum!

From the block and tackle I lowered the entire powerhead down onto my welding table, which has a half inch thick piece of plate steel for a top so it made for a nice sturdy workbench.  I then just pulled the boat trailer out of the garage and I had all the room in the world to work on he motor.  I was talking to Dave Ulvaan about this project, he too had something similar he did in his garage.  He was repairing the transom on his boat and had to remove the outboard from the transom, so he constructed a simple beam on stilts that would allow a block and tackle to remove the outboard from overtop of the transom, something I would have used had I not used the hooks in the ceiling.

Once the motor is laying on the bench (photo) give it all a good looking over, inspecting all the wiring and hoses for wear and tear.  Its also a great time to get the brake cleaner to work and clean up all the areas that are dirty, although I must say this motor was pretty spotless, and luckily no other oil leaks anywhere other than the pump and bottom gasket.

It is extremely important to take extra care and time when cleaning up surfaces which are referred to as "mating " surfaces.  This means that it will be a metal to metal contact area and chances are there will be a gasket involved.  In my case there were two small rubber O Rings that sealed the oil pump against a metal surface and then the metal gasket that went under the motor.  There was no gasket sealent used in either of these spots so it was important that the metal surfaces be spotless.  I use a razor blade to clean these areas first, then if necessary a Scotch Brite pad and then brake cleaner.  Out of all the pictures I took I forgot to take one of the area inside the cowling that I had cleaned up, it would have given a good idea as to what clean should look like.

The oil pump, here (photo) is when its still attached to the bottom side of the motor.  What you can't see very well is that the seal (photo) is really chewed up, and I have no idea why.  I replaced the water pump in the leg 3 years ago and had to run the drive shaft back up through this seal but never would have done that much damage and, it would have leaked long before now.  Who knows, maybe a bad seal to start with.  As previously mentioned this pump has 5 seals in it, and after pricing them out up here in Canada I figured it was just about as cheap to replace the entire pump, if bought in the USA.  Pump up here, $600. price down there, $300, go figure! 

There was one other area of concern with the pump area and that was with the crankshaft itself.  Luckily, I did a little research online and found that in the first couple of years of the production of this motor they used a very soft steel in the crankshaft.  While there is no concern for the overall strength of the shaft there was a concern, and not voiced by Yamaha of course, of the pump seal wearing a groove into the shaft!  After removing the oil pump it was obvious that this indeed is what happend to my shaft, and could also be part of the problem with the oil leak.  Over time the groove would get so deep that even though the seal is not worn out, it can no longer apply enough pressure on the sides of the shaft to prevent oil from leaking, especially hot engine oil that is also under pressure.

The solution was simple, if you knew about it ahead of time.  The Yamaha "geeks" up here knew nothing about it of course but the pro's on the IBoat forum certainly knew about it and even provided the Yamaha part number for it.  It's called a Speedi Sleeve, and they (photo) have been around for years for exactly this type of situation.  All they are is a hardenen stainless steel ring that fits exactly to the size needed for each particular application.  They come with a small metal tool to install them, that just fits loosely overtop the Sleeve and you hammer it on, in this case, the crankshaft (photo).  Now, I must say that this is easier said then done, as the tolerences are so tight, it can make it ugly to get it to go on straight!  They recommend heating the Sleeve in the oven to expand it and then just "slide it on", ya, right.  The only thing that worked in my case was a bigger hammer!  The end result speaks for itself though (photo), a nice new smooth surface for the seal to ride on, hopefully no more leaks!

Once the Speedy Sleeve was in place the oil pump, along with new O Rings, bolted back in place with 4 bolts.  I also smeared synthetic marine grease on all the new seals to make sure they were lubricated from the start.  All the "mating" surfaces that you see on the bottom of the motor were cleaned, as were the ones inside of the cowling.  The metal gasket was put in place inside the cowling, the motor lifted up and then carefully placed back down onto the leg again.  I had my buddy Knuckles come over for this procdure, it made it much easier to line up the drive shaft to fit it inside the pump while I lowered and moved the motor into place.  I must say we did a helluva job, first shot at putting it in and it just popped back into place like nothing!  I then put all the bolts back in their appropriate spots and torqued them down as per the specs in the manual.  Yes, you need a torque wrench for this kind of work, there is nothing more important at this stage of the game then to make sure each bolt is tightened exactly the same as the rest, because that's what ensure's a proper seal on that new steel gasket.  In fact, after I got the motor back together, I ran the motor in the driveway and warmed it up a bit, then re-torqued the bolts and, the next morning once the motor had cooled down I re-torqued them again!  And, after the summer and when we get back into cool mornings I will again re-torque them, you can never be to careful, especially when your a winter angler like I am.

If you tagged all the things you took off at the beginning of this exercise, its just a matter of doing everything in reverse and triple checking that you've missed nothing.  Like I said, this wasn't brain surgery, and a little time and patience can save you a ton of dough when you can do these simple things yourself.  Parts wise I saved over $400 and labour wise probably at least a grand, if not more.  For those who say they're to busy and don't have the time then I'd say they probably make to much money and don't mind spending a buck at the local marine place.  For those who say they don't have the knowhow to do such a job, think again, its much simpler than it looks, really.  Even if you just took the motor off and took it into your dealer to make these repairs you save a chunk of change, more money for hooks!    Sherm