1972 evinrude 25253r prop shaft seal

webbrs

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I have seen reply's to a thread about water intrusion refer to the prop shaft seal and am wondering if they are talking about the seal inside of the gearcase head assembly OMC 0383757 or the o-ring around the assembly? I am doing my gearcase and it had milky oil. I see some very light wear (mostly shine) on the prop shaft where this seal rides but there is a groove, as well as the ridge the assembly seats onto. The seal is not damaged and feels pliable but is a direct line to allow water in. I know I will need to pressure/vacuum test but if it looks good I don't want to spend the $150 to replace the gearcase head assembly (and prop shaft) unless absolutely needed. Even then I don't want to...
​There was also a reply that said to remove the washer and replace the seal? None of the parts catalogs show a part number for the seal or that is comes apart, it just shows the assembly. This assembly appears to be pressed together. For what I see the bearing is pressed into the assembly and the seal is inserted before the bearing is pressed in. The only reference to a bearing that is removable is the forward gear bearing and it slides right out.
 

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racerone

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????----Pop that washer out.---Remove the seal.----measure the propshaft diameter.----Measure the bore of the bearing housing .----Look for a replacement seal.---Nothing to it !!
 

webbrs

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??? not seeing any washer and nothing is moving. this thing costs 150 bucks so you can understand my hesitation. can you elaborate?
 

racerone

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I am not sure why you are not seeing this.-The washer is installed to keep fishing line from getting at the seal.---Pop the washer out and pop the seal out.---Post the dimensions accurate to a few thousandths of an inch !
 

webbrs

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After more research the seal is in the kit Mallory kit #9-74105 found at amazon of all places. I already ordered all of the other seals for the gearcase and I can find no reference to the actual seal part no. anyone who has done this and knows of the part no., would be helpful if I could order only the seal.
 
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F_R

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Jul 7, 2006
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Simple, go to the parts book for a couple of years newer and look for the seal number. It can be replaced without replacing the whole gearcase head.

EDIT: Er, maybe that should be a couple of years older. It's there someplace. 1968 shows 313284 seal.
 
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AlTn

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Mar 9, 2010
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you may have to add a 0 to the beginning of that part no....0313284....your seal kit probably has a seal that is intended for the propshaft, but the rubber portion is not as "robust" as the original seal, at least that's been my experience with seal kits...given thought to replacing the shift rod seal?
 
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