Mercury 850 Water pump Impeller

[Ace1948]

I have a 1975 Mercury 850 that needs the impeller replaced.
Does the shift linkage slide out when I remove the bolts in the foot?
Or there something that need to be taken loose?
Can some one give the the OMC number for the impeller?
My motor number is 4423397.
Thanks for any help.

[carholme]

Ace;

The s/n comes up as:

85 850 4-cyl 4366802 4590511 1976 USA

From here:

http://www.marinshopen.se/Motorer/Om...7/Default.aspx

Parts listing:

http://www.crowleymarine.com/mercury-outboard/475.cfm

See item 29 here:

http://www.crowleymarine.com/mercury...rts/475_20.cfm

Gerry

[Chris1956]

Ace, Set the motor to neutral. Now remove the bolt that holds on the zinc anode. Now you will see the hidden bolt. Remove all 5 nuts and the hidden bolt and the gearcase should slide free of the midsection.

Change the impeller, and grease the driveshaft and shiftshaft. Now with the notor tilted up all the way, shove the driveshaft into the midsection. Line up the watertube, and rotate the flywheel by hand until the splines mate. Now mate the shiftshaft splines. Installing some nuts can help, but only use fingers to take up the slack.

[Ace1948]

Chris 1956 the foot came off just like you said thanks .I got my impeller repair kit today kit number 18-3217 it has a plastic tube about 3/4 Dia with a hole Thur the center with a 1/16 wall about 3 inches long.I don't know where this tube goes can any one help me? I did not remove the bottom part of the pump.I also have some rubber 0 rings that I did not remove.I am assuming this kit fits more than one motor.

[Ace1948]

Thanks Chris 1956 for your help.I had already removed the foot from my motor before I read your reply.The only thing that I did not do is put the gear shift in neutral but I had it in forward gear when I pulled the foot.I hope I did no mess up any thing.I got my impeller kit today part #18-3217 I had planed on installing it in the morning.This kit has a water tube line sleeve how does it work?
This kit has sevrial rubber O rings that I have not removed.I think this kit fits different motors.I have not removed the bottom part of the pump.

[merc850]

Here's the diagram: the Oring goes on the pump base and the tube goes onto the water tube and into the pump top.

Lower-Unitsdriveshaft.jpg

[Ace1948]

Thanks to every one for all the help. I looked on the internet for the lower unit diagram but could not find one this will will be a great help Thanks.

[merc850]

Watch ebay for manual, sometimes on disk.