THE FINER POINTS OF YAMAHA WATER PUMP REPAIR: QUESTIONS

[hotajax]

Am doing my water pump very soon. There are two schools of thought on what to do with the gearbox before removing the lower unit. First Method: Leave the gear box in neutral. Plus side to this method is to make it easy to turn the drive shaft by hand when you are pressing down on the cartridge insert over the impeller, and supposedly make it easier for the impeller blades to go into the cup. When re-mounting the lower unit, it will be harder to line up the splines on the upper end of the drive shaft because you will have to lower the lower unit, and turn the drive shaft a little. Sort of a trial and error method until the splines line up, until you can bolt the lower unit into place. Second Method: Put the gearbox in reverse before taking off the lower unit. Plus side to this method is that when you are lining up the splines to remount the lower unit, all you have to do is turn the prop to move the drive shaft enough for the splines to line up. Force the impeller into the cartridge insert before placing it onto the drive shaft.

OTHER QUESTION: Does it matter which way the blades fit into the cartridge insert? Will the drive shaft rotation orient them in the right direction? Thank you, gents.

 

[rpc]

Try searching u tube for your engine. I found a number of good videos on how to diy. I changed both my water pumps this past spring and found them a great help.

 

[dduflo]

I have changed mine by following a video on UTube. Very helpful especially when reassembling the watchers and spacers. Be sure to mark your trim tab so you can install it to same place. I put 2 small sawhorses side by side as a way to stabilize the unit. Put engine in gear when you are finished and try to spin prop to be certain you inserted the shift rod correctly. Learned this the hard way and had to take it off and do it right? I also removed my stainless props to lighten the unit. I bought the whole kit but really only needed the impeller. I am in fresh water and the bolts came out easy with no corrosion. Different story if you have been in salt water for an extended time period. Good luck

 

[Andrew93]

I have changed a number of water pumps of v6 Yamaha's, mainly OX66's. I always have left the motor in neutral, only once did I slightly struggle lines up the splines but it wasn't a big deal.

I have always done the whole housing. If you do the whole housing there is a gasket /o-ring and a retainer on the discharge of the pump housing, you will have to move those to the new one. First time I forgot to do this and resulted in low RPM overheating right away.

I always spin the impeller into the housing with the splines facing the proper direction. I have read that there is a possibility of some not flipping over but no one seems to confirm that it can happen. It is easy enough not to risk it though. I use the old one to determine the right direction.

Only time I snapped bolts was on an older 150hp that did not have a pump changed in who knows how long. I was easily able to get them out after with PB Blaster and vise grips after the lower unit was slid off over the broken bolts. Also be careful removing the retained on top of the impeller itself. I lightly pry it with a flat head screwdriver.

Its an easy job and after 1 or 2 you will have it down to a science.

 

[hotajax]

For Firemedic: The gasket/o ring on the output side of the housing: Is it prone to getting lost easily when you take off the lower unit? Thanks for your tips, gents. I appreciate it.

 

[Andrew93]

For Firemedic: The gasket/o ring on the output side of the housing: Is it prone to getting lost easily when you take off the lower unit? Thanks for your tips, gents. I appreciate it.

It is not pone to getting lost, you will see the retainer cap and the o-ring under it (its pretty thick and rugged). The first time I did a water pump I forgot to move this over to the new housing and is something that could be easily overlooked.

 

[Rustygaff]

When re-installing the foot, make sure the motor is vertical so the shift rod lines up with the spline. Don't ask how I know this......

 

[HMBJack]

I must have done 10 or 12 of these and used to always keep the engine in neutral but after a few frustrating installs, I now keep the engine in Forward Gear. Keeping it in gear seems to be easier and avoids the hassle of lining up the shift shaft splines.

 

[rmcderm313]

Just did my 2001 Yamaha 175HPDI. I left the shifter in neutral when I removed it. I was having a bitch of a time getting it back in. The shift rod just wasn't allowing the lower unit to insert far enough. I knew it was the shift rod because if I intentionally moved the shift rod to the side of the tube that it is supposed to go into, I could (very gently) slide the lower unit almost all the way on.

Turns out the lower unit somehow got into forward. I swear I didn't touch it, and I was careful. I suspect spinning the prop to get the impeller under the housing at some point moved it from neutral. In any event, once I figured that out, it slid right on.

Moral of my story, check both the remote shift lever as well as the lower unit to ensure both are where you thought they were...

:bang

The struggles with the woodruff key are legendary.... I now file my key down and coat it in anti-seize. But if you are changing the pump where someone else has done the last key install, you never know what you're going to get. Lots of guys claim to have this figured out with different methods, but I've struggled each time I'm changing someone elses install.

IMHO this video is the best Yamaha waterpump tutorial.. https://youtu.be/BRQo3rYTj-U

Good luck!
Rob

 

[seasick]

I have a trick for the woodruff key that has never failed me yet

Using a Dremel type tool and an abrasive disk, cut a slit lengthwise in the surface of the key. Cut as deep as you can go without cutting into the drive shaft.
Now squeeze the key with a vice-grip to make it narrow ere. Tap ot the key with a hammer and chisel if necessary.
I have seen folks heat the shaft with a torch but i don't like that method. It can be too easy to damage the temper.
Every now and then, the key comes out easily without all the slicing and dicing.

 

[jbrinch88]

I've always left any lower I pull in neutral. You can always move the flywheel a bit to line up the driveshaft more easily.

I've always used a hammer and pointed chisel on the keyway. Hit from top angled slightly and the bottom should start to bulge out. Then just pry up on the bottom with a screwdriver and it pops right out.

Yes the blades on the impeller should be inserted correctly. Outboard impellers don't usually correct themselves. Inboard impeller pumps/pulley driven usually will.

 

[hotajax]

To JBrinch88: I left it in neutral. It slid in easily with a little red grease. Actually, alot of red grease. I love that stuff for a lot of reasons.