Yamaha water pump replacement

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Lady of the Lake
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Yamaha water pump replacement

Post by Lady of the Lake »

Lady of the Lake is on the hard getting new bottom paint. The marina is a Yamaha repair center and recommends that I have the outboard water pumps replaced while she is out of the water. In addition to replacing a wear item, it insures we can get the bottom case bolts out and clean them up for the future. They are 2003 and have less than 700 hours on them. They are very clean, no corrosion noticable at this time.

Seems like a good time to do this while they are accessible. Sound like a good idea or am I wasting money? Anything else I should do while she is out other than replacing the zincs on the motors?

Thanks,
Sam
Sam and Gina Densler
s/v Lady of the Lake
PDQ36 Hull #15
Punta Gorda, FL
amytom
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Re: Yamaha water pump replacement

Post by amytom »

Clean up the hold down latches?

The dock looks empty without the Lady there.
Allezcat
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Re: Yamaha water pump replacement

Post by Allezcat »

Sam,

Water pumps last a long time but you are right about getting the lower unit apart. Be sure NOT to pound on the anti-cavitation plate to seperate the units. Also if you do replace the water pumps be sure to remove the plate under the impeller and clean out the cavity. It tends to clog with salt. Lastly, I would suggest applying non-seize compound to the studs and steel locating pins before reassembly. Also I would change the oil in the lower units and replace with fresh Yamaha oil. If the drain oil is light brown in color or there is any seawater drained, have the unit pressure checked for a bad seal (shift rod, drive shaft, or prop shaft).

Chet
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Root
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Re: Yamaha water pump replacement

Post by Root »

Hello Sam and Gina,

I am a preventive maintenance nut and had concerns about our water pump impellers. (see earlier posting below). I have since made two discoveries that may ease your mind. One: The Yamaha maintenance manual does not even address replacing impellers and the ones I bought are far more robustly made then any I have seen before. Two: I do not recall a thread in this list serve addressing failed impellers in 1999-2004 and later Yamaha 9.9. Our impellers continue to function perfectly.

Earlier Posting: The impellers are working fine. I have good water flow and no overheating problems but, with manufacturing dates of 1999 and 2000 respectively and 400 hours on both, I suspect the water pump impellers are soon to fail.

How do you loosen and remove the lower unit from the Yamaha 9.9s? I have removed the nuts from the through bolts, soaked the joint area in PBR, struck the unit on the obvious strong points with hammer and block of wood, drove a chisel into the joint, pulled and cussed at them and nether one will budge. Any advice?

Ray & Paula
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Marc Gershel
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Re: Yamaha water pump replacement

Post by Marc Gershel »

I'll try to describe what I did. Remove the nuts. Replace them with barrel nuts.(longer nuts used for connecting 2 threaded bolts). Do not tighten the nuts, leave about 1/16" space. Put a C-clamp over the top of the flange, and over the bottom of the nut. Tightening the clamp will pull the flange down the 1/16" to the top of the nut. Go slow and try using 2 or more clamps. When it get down to the top of the nut, if it's still not loose, loosen the nut another 1/16" and try again. This acts like a prop puller. It's not easy , but it does work, without damaging anything.
Marc
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Re: Yamaha water pump replacement

Post by Allezcat »

Ray & Paula,

I will try to describe my crude lower unit puller which will remove the most stubborn units.

1-Fashion two 12" long 4X4s by hollowing out one side of each to the contour of the lower unit above the gearcase.
2-Clamp these around the lower unit above the gearcase using two 1/2" threaded rods 12" long with nuts and washers (not too tight)
3-At the center of each 12" 4X4 drill a 9/16" hole parallel to the driveshaft and insert a 36" long 1/2" threaded rod with a washer & nut on top end
4-At the other end of the threaded 36" rods fit a 12" 4X4 with washers & nuts
5-Place the engine with the attached puller on a concrete floor with aft end down toward concrete (handle up)
6-using a large sledge against the lower 4X4, drive the unit off

I have used this crude gadget many times on badly corroded engines with 100% success and no damage after having Yamaha dealers ruin an engine by using heat to the point of melting the aluminum and breaking the casting.

Chet
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