Ready to rebuild my QD-19 lower unit

[samo_ott]

I finally have got all the parts, gaskets & O rings together required to rebuild the lower unit on my Johnson 1958 10hp but have a few questions. My local OMC guy said to use the 3M #847 tube of goop around the spagetti seal and the brush on OMC gasket sealer around the prop seal O ring and under the water pump housing. Is this correct and under the water pump housing do I coat both sides of the gasket? Also do I use the goop or sealer anywhere else? Any other tidbits of advice for me? thx...

p.s. I also followed the forum advice and ground down the tip of a 5/16" metal rod to pop out the shifter bushing to get at the O ring and it worked great - thanks!

 

[OBJ]

Re: Ready to rebuild my QD-19 lower unit

Won't hurt to coat both sides of the gasket samo.

The 3M stuff will hold the spagettii oring in place. What you can do is right before you mate up the gear case halves is to apply a light coat of the OMC gasket sealing compound to the oring. It'll help fill in any little voids. Also, cloat the threads of the screws that hold the halves to gether.

I will usually brush the shift rod bushing with a light coat of compound before putting it back in. Makes it drive in a little easier and help prevent any corrosion around the bushing.

A little compound around the shift yoke screw that holds the shift yoke in place is good also. Will help seal the small oring on the screw.

 

[samo_ott]

Re: Ready to rebuild my QD-19 lower unit

Thanks OBJ. Another question, coming out of the top of the water pump, around the driveshaft, is a 1.5" extension or so with O rings on each end. What's that for? It appears to do nothing and I took 2 lower units apart, 1 had one and 1 did not (same year and model). The tops of the water pump housing's are different also depening on if the extension is there or not... thx...

 

[OBJ]

Re: Ready to rebuild my QD-19 lower unit

It's a seal to prevent exhaust gasses from possibley entering the water pump causing the pump to stop pumping. It also keeps the gasses from around the drive shaft and bottom of the block.