1973 johnson 25hp 25R73A

[Roadking57]

Its alright. We are using our RV which is parked in the driveway! Always have an out

 

[Roadking57]

Okay! New Tankless water heater all installed!! Now I am cleared back to boat engine stuff!!!

 

[clemsonfor]

Okay! New Tankless water heater all installed!! Now I am cleared back to boat engine stuff!!!

Good work!!! Now you can get back to the fun work!

 

[Roadking57]

Okay! I disassembled the 73. Found it to be a rusted piece of @#$%. Crankshaft rusted bad, journals pitted. Piston rods and bearing pins rusted bad, pistons look only slightly better than the ones I took out of the 70. Soooo so much for that engine, maybe later. So now I order new pistons and continue with the 70. Its innerds look almost new compared to the 73. (both 25hp johnsons).
Anyone know for sure which way the top ring chamfer is supposed to go? the 73 rings were not stuck (like the 70 was). The beveled edge was installed facing top of piston.

 

[racerone]

?----The top ring will only fit one way!!

 

[Roadking57]

Ahh okay I see that now that I cleaned up those old pistons.
I was cleaning up gasket surfaces and noticed 3 of 4 rubber mounts that hold the lower motor cover on were broken. I tried to remove the nut from last one to facilitate cleaning and painting and it broke off with hardly any torque. Ok I figured no problem let me order some new ones if they are available...
$39 each? Wow! No way. Not spending $160 plus on rubber mounts! Is that normal? Seems kinda high to me.
Anyway I found some online I think will work just fine. 4 set for $16 on good Ol, Be here tomorrow, Amazon.

 

[Roadking57]

Question
After searching this forum I havent found much on what brand of portable fuel tanks are better or to stay away from. I think I've read Attwood's are junk somewhere. Anyway I'm in need of a new tank soon. What would y'all buy? I need fuel line and all.

 

[Crosbyman]

older plastic tanks are solid ...try to find a Mercury brand fuel tank on craiglist or similar sites.

similar to this one... I have 2 and they are plenty adequate plus they have an internal reserve
section .

Moeller Scepter Topside Marine Fuel Tank with Gauge (6.6-Gallon), Fuel Tanks - Amazon Canada

Moeller Scepter Topside Marine Fuel Tank with Gauge (6.6-Gallon) in Fuel Tanks.

www.amazon.ca

 

[Roadking57]

okay further disassembly causes me to need a motor cover to exhaust gasket

0308292​

Im running into NLA.
My old one is in one piece but squashed pretty bad, and its very soft,& semi thick.
Any suggestions?

 

[Roadking57]

Question
Whats this hole supposed to be? Grease fitting?
before and after removing corrosion on engine pan

 

[Roadking57]

Maybe I should get this post moved to Boat Restoration building and repair? Just a thought.

 

[tphoyt]

I would say that hole was either a grease fitting or a tensioning screw for the steering.

 

[Roadking57]

Had to come back in here to say,

My New Pistons are Here!!!!!!!!! The rings came installed. I did notice they have small tapered ends. Do I need to measure the gap like car engine rings and file them if needed? I noticed the pistons have small pins to hold the rings from turning inside the grooves at the wrist pin on opposite sides.

 

[Roadking57]

Okay!! returned home from work and its christmas again...sort of. Another box of boat motor parts!!!!! The Thermostat and carburetor kit has arrived.

I have searched all over the internet for the motor cover to exhaust seal. Im afraid its NLA :-( Gonna have to find some semi soft material and make it myself. Anyone else make one? If so what did you use?

 

[tphoyt]

I made one from gasket material I got at Napa auto parts. I don’t have a part number but I can say it’s blue and 3/64 in thickness.

 

[Roadking57]

Well, after cleaning the black off the old gasket a bit I discovered its made out of thick cork. Thank you for the tip tphoyt! I do have a napa near me I will stop by there otw home and inquire if they have anything like that. Otherwise its back to the good 'Ol internet. See if I can order 3/64th or thicker roll of cork. Maybe make several and sell em?

 

[Roadking57]

Removed the upper and lower plug screws and about an ounce of gear oil drained out. Looks dark brown but no water present. Still going to open her up, inspect, and reseal.

 

[racerone]

There should be more oil than that.

 

[Roadking57]

There should be more oil than that.

Thats what I thought too

 

[racerone]

Do a full inspection before spending beer tokens.----Don't overlook the o-ring on the shift rod if you reseal the gearcase.