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When I pulled the driveshaft out of two different Johnson TN-28’s,
I did not find a spring for the carbon seal assembly.
A carbon seal, and a thin washer dropped out of both motors though,
after I had the driveshafts pulled out of the motor. You’d think
if there was no springs that the said carbon seal and washer would have
come out with the driveshaft, not fall out after the shaft was removed.In looking at the Johnson bulletin, it appears the carbon seal is a
“cup” affair, the the spring seats inside. Both of the carbon seals
I found did not have a recess for a spring, but both had an o-ring on them.Am I missing more than the spring for each motor?
Does anyone have measurements of an actual TN-28 spring?
I found a spring in my parts bin, but it does not appear it was for
this use.Does anyone have a parts diagram for the TN-28? I have a pdf for
the TN-25/26, but I’m not sure of all the differences…… I know the
magnetos are different.Thanks.
Prepare to be boarded!
In looking at my TN-25 / 25 parts manual, it looks like the parts
that came out of my TN-28’s (less the missing spring) might
be carbon seal assembly parts from a TN-25 or 26 motor.The diagram appears to show the “spring”, a “washer” atop of it,
and the “carbon seal with o-ring” above the washer.The Johnson TN-27 / 28 Service bulletin parts and assembly
look a lot different.My drive shaft appears to be the TN-28 style with the pressed on
collar below the spring.Now What?
Prepare to be boarded!
Seeing how I’m missing the spring for the carbon seal assembly,
I order a complete, used” assembly off of Ebay, from a latter
Evinrude 7.5 hp, I believe. From what I read, those components
should work on the TN-28, and are the same parts shown
in the Johnson “upgrade” Service Bulletin…….. time will tell anyway.What I’m wondering now, is it possible to install the carbon seal
components on the driveshaft, and slide the whole works up
thru the mid section of the motor, or does one need to pull the power
head, install the midsection with lower unit with driveshaft, and set the carbon seal
assembly onto the top of the driveshaft?I could not find anything in the 3rd or 10th edition manuals to answer
my questions.
Thanks.Prepare to be boarded!
If this is like a TD powerhead, there are actually two gaskets involved with removal of the powerhead. One sits horizontal with the three studs, and the other sits vertically.
Looking at your parts diagram, it does show both gaskets. PN 302355 & PN 41-36.
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