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800 Outdrive Water Pump Impeller

R

rosbullterrier

Member
"I read these should be change

"I read these should be changed every 2-3 years and my boats been laid up for about 10 years . .

Well, the swivel housings came off fairly easily, then four large bolts undone and the impeller housing tapped out. The top bevel gear has then to be hammered out.
But the central shaft is still held in place by the lower roller bearing. To remove the impeller housing it seems this must be removed. I dismantled both outdrives to prove that just one wasn't stuck, but no, both shafts appear to need pressing through that lower bearing.
It seems a difficult process to replace a pump impeller - or is the design to prevent them without the equipment?"
 
"[i]and the impeller housing t

"and the impeller housing tapped out

you lost me after that... why are you taking the top bevel gear out to change the impeller?

Once you get the w/p shaft and impeller out, put the new impeller in and reassemble it. don't forget the "cog" seal and metal clip to hold the grease in the spline. "
 
"I think I have the terminolog

"I think I have the terminology right.
The top bevel gear is at the top end of the W/P shaft. The W/P impeller is inside a housing which the shaft runs through. This housing appears to be held around the shaft by the top bevel roller bearing and a bottom roller bearing.
(Which I need to remove, to remove the impeller housing, to remove the impeller?)"
 
"The bearing housing which fit

"The bearing housing which fits on top of the impeller housing.
The bearings need removal to remove this housing and get at the impeller.
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Bearing-housing-800
 
"no, that housing can stay in

"no, that housing can stay in the upper gearbox. The impeller is underneath. If you do want to take that whole assembly out, the bearings will come with it. I rarely bother though. I just swap the impeller in from underneath.

The impeller is keyed to the shaft that connects the upper gearbox to the lower unit. "
 
"As you say the impeller is ke

"As you say the impeller is keyed to the shaft which connects the lower unit to the upper gearbox.
The upper gearbox is the swivel housing. The connecting shaft is held in two taper roller bearings in the above bearing housing.
The impeller is sandwiched between the bottom of the bearing housing and the stainless end cap. The shaft needs removal to separate these to access the impeller. I purchased a puller today.

Unfortunately one of the bearing housings is broken (corrosion)
376035.jpg
800impeller1"">
376036.jpg
800impeller2
 
"the water pump shaft is not h

"the water pump shaft is not held in by any bearings. It isn't held in by anything normally. Yours must be rusted in because the splines were not maintained.

The two ends protruding out of what you have there are the ends of two separate shafts. A gentle tug with 2 fingers should remove the water pump shaft (if the spines are greased every few years with an impeller change) Hopefully you can salvage yours, but I doubt the splines will be reusable. When rusted they usually corrode to failure.

Might be best to look for a good used upper with same ratio."
 
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