Logo
FULL SITE MENU

7.5 hp '58 Johnson expansion plug

D

DragonflyMU

New member
The expansion plug on the right side between the cylinders in the water jacket popped out. I used the engine a week or so ago, and it has only been sub 32 once since then. And that was about 29 degrees. The motor was on the transom and has apparently drained okay for the last 48 years that I have owned it. My surprise when I cranked it up yesterday morning. I last used it about 3 weeks ago.

Anyway, I have ordered the expansion plug. It looks quite a bit different from the one in the top of the cylinders' head. Do you just tap the new plug into the hole, or is there a more expansive method.

Any assistance would be appreciated. I can post a pic if it is possible on this forum. I think it is about the first time I have actually posted something.

Dragonfly
 
The new plug is dished. Place it in the hole with dome side up. Then using a hammer with a suitable punch or rod tap on the dome to flatten it out. That expands it tightly in the hole. When tapping on it, do not go beyond flat, as that will dish it in the opposite direction and it will get loose again.

Cold weather probably had nothing to do with it. They get rotted away and fall out here in Florida also.
 
Right, Gator. The water will self drain, unless some was trapped from blockages in the water jacket. Don't they make a salt residue remover for your equipment used down in the ocean? We are so lucky here up northern Minnesota way. Our old motors are still pristine. Did you see that demonstration with cutting a large circle through the ice and powering the ride with the old Johnson.....??? Its on YouTube. We are half insane up here.
 
timguy said:
Right, Gator. The water will self drain, unless some was trapped from blockages in the water jacket. Don't they make a salt residue remover for your equipment used down in the ocean? We are so lucky here up northern Minnesota way. Our old motors are still pristine. Did you see that demonstration with cutting a large circle through the ice and powering the ride with the old Johnson.....??? Its on YouTube. We are half insane up here.
Click to expand...

Yeah, I saw that video. You guys find lots of ways to have fun, don't you? As for salt water, it corrodes stuff, no matter what you do. Salt residue remover?? My personal opinion is better left unsaid. I will say that water is the solvent for salt. Why pay more?
 
Back
Top