Home › Forum › Ask A Member › 1972 25 HP Johnson Outboard
- This topic has 42 replies, 14 voices, and was last updated 4 years, 5 months ago by
fleetwin.
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December 7, 2020 at 1:07 pm #224500
I’ve used liquid wrench to unstick rings. Have heard that Kroil works good too, but haven’t tried it.
DaveDecember 8, 2020 at 10:12 am #224601OK, so the powerhead sure looks OK on the inside….What was seizing it up? Or, perhaps the gearcase is seized. Those head bolt studs will come out with a little heat. The block/head surfaces look OK also…. What is the grey stuff on the head gasket??
December 8, 2020 at 10:19 am #224602Just spay some WD-40 and it comes out. A bit rust on the lower cylinder wall (see the picture) and the piston (red circle). Does it look acceptable and could be cleaned up with a quick honing? Should I order the new ring or just use the old ring. New ring is too much expensive!
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This reply was modified 4 years, 5 months ago by
Evinrude 25.
December 8, 2020 at 10:23 am #224606Looks pretty good to me. “Never judge a book by its cover”…..
December 8, 2020 at 10:32 am #224611There are 3 things seized up: The mag plate got seized up with the block neck, the gear case got seized up and the lower piston got seized up at the intake port. The water contacts the piston at the intake port (red circle on the picture). I have removed all the bolts out without heat. I have no ideal of the grey stuff on the head gasket. Only ATF contacted the head gasket when I removed it so. Not sure what you refer to the gray stuff.
December 8, 2020 at 10:36 am #224615You have got the area circled that I am referring to…. Probably just some schmutz that the head was laying on after removal. The only reason I pointed this out was to emphasize the importance of inspecting the block/head mating surfaces carefully. This series of engines is known for aluminum erosion in this area….
OK, so the gearcase is seized also….You better pull that apart to see if it is salvageable before going too much further….December 8, 2020 at 10:59 am #224616I am glad it turns out good inside. By the look of out side, I expected all bearings, crankshaft got rusted since it was in the water and people just hang it in the garage for a couple years.
So It will be my winter project to get this one back running. I had the learning experience from my 1973 20 Hp so this one should go well.December 8, 2020 at 11:10 am #224617December 8, 2020 at 11:34 am #224620Well, the block sure “looks good”…Just wondering what the stuff is that seems to be stuck to the head gasket, you see it don’t you? The area to check in the gearcase is/are the bushings cast in for the driveshaft/pinion areas. Running the gearcase with no oil tends to wobble out these bushings, that are not replaceable….
December 8, 2020 at 1:19 pm #224634Looks like you lucked out! On your piston photo, on the piston on the left, be sure to spin one of those rings around so the gaps of the two rings aren’t in-line.
Dave -
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