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Outboard Lower Unit Removal
Posted: Mon Apr 14, 2008 2:26 pm
by Root
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
Wind Seeker
PDQ 36 #95
Re: Outboard Lower Unit Removal
Posted: Mon Apr 14, 2008 8:38 pm
by duetto
hi ray,
one typical/possible culprit is salt packed around any hole that the thru bolts go thru. another is the spline of the driveshaft stuck into the bottom of the crankshaft due to mix of burned exhaust/salt/heat/etc.
the first is going to require getting liquid penetrant onto the salt.
Re: Outboard Lower Unit Removal
Posted: Mon Apr 14, 2008 11:42 pm
by Allezcat
Ray,
Do not pound on the cavitation plate. It will break.
Yamaha dealers sometimes use heat (a torch) at the joint but I had one dealer ruin an engine by melting the aluminum.
I have devised a crude but effective device which clamps around the lower unit and uses rods to a 4X4. I then seperate the lower unit by using a sledge against the 4X4. I can send a photo if you send me an email.
Chet White
Allezcat 36010
cswhitejr@comcast.net
Re: Outboard Lower Unit Removal
Posted: Tue Apr 15, 2008 11:16 am
by Lady of the Lake
Chet,
Upload the attachment right to the forum. Right below the text area you will see a tab for "Upload Attachemnet". Select that tab and then select your file to upload. Then we can all see it!
Re: Outboard Lower Unit Removal
Posted: Tue Apr 15, 2008 11:08 pm
by Marc Gershel
My method may be hard to explain, but I'll try. First I remove the nuts, and replace them with barrel nuts. I think that's what they're called. They're long nuts. I thread them on to within 1/8" of being tight. Then put a C-clamp over the top of the flange, and the bottom of the nut. When you tighten the
C-clamp, it acts like a gear puller. Then go from bolt to bolt, tightening the clamp a little on each one until the the lower unit lets go. Is that understandable? I hope so.
Marc
Re: Outboard Lower Unit Removal
Posted: Thu May 08, 2008 11:04 am
by Root
Thanks to everyone for their helpful suggestions and advice. I was not successful in getting the units loose and my yard time was limited so for now, with the aging impellers in place, I cruise with my fingers crossed. Ray