1973 johnson 25hp 25R73A

[Roadking57]

Ok, I'm back from Sun n Fun fly in vacation in Florida! Built my new engine stand. So far I like it.

 

[tphoyt]

Welcome home.
You you had a Blast.

 

[clemsonfor]

Did you buy the motor there? Or is this just a random post about the engine stand you built and your just letting people know what engine happens to sit on it right now?

 

[davidmbv]

Great motors when they run good. I liked my 71 so much I picked up a 70. The early 70’s 25hp OMC’s are super light weight and even when they “act-up”…they sill managed to limp back to the dock.

 

[Roadking57]

Clemsonfor , I had a 4 pg run on post about a 70 25hp I've taken apart. It was ran hot and pistons destroyed so bad I couldn't remove the rings even after boiling them in water! I found the 73 engine down in savannah just before I left on vac. It has a starter and bracket and I paid a buck fifty for the entire motor. I was able to spin it by hand (head was removed). So I had hoped it had compression and maybe put it back together.

But, I used the old head gasket which really didnt look too bad and bolted the head back on and the exhaust side cover to check compression. Sad to report its a dismal 30psi on both cylinders. Unless I left a cover or something off this little motor needs new rings too.
Maybe I can soak the cylinders with penetrating oil for a few days and recheck it.

 

[Roadking57]

Welcome home.
You you had a Blast.

I did Sir! Escorting airplanes with motorcycles! Best of two worlds!

 

[Roadking57]

Great motors when they run good. I liked my 71 so much I picked up a 70. The early 70’s 25hp OMC’s are super light weight and even when they “act-up”…they sill managed to limp back to the dock.

I'm hoping so. I repainted a 14ft Aerocraft v bottom with a 40hp max rating. I want to put a 25hp on it. Since I cant seem to order a new one Im wanting to get at least one of these two johnson 25's on my boat

 

[clemsonfor]

I'm hoping so. I repainted a 14ft Aerocraft v bottom with a 40hp max rating. I want to put a 25hp on it. Since I cant seem to order a new one Im wanting to get at least one of these two johnson 25's on my boat

I'm getting my Late Father in Laws 25HP rude in running order for brother in law. I know it's sat at least 10 years. Did the carburetor, fixed the screwed up out adjustment shift shaft and now rebuilding and resealing the lower unit. It sits on a StarCraft 14ft V bottom.

 

[Roadking57]

what year is the rude Clemsonfor?

 

[clemsonfor]

what year is the rude Clemsonfor?

73

 

[clemsonfor]

I had a 1969 25HP rude on an older boat I had. Motor ran like a sewing machine and would idle way way down and just put around like that if you wanted to go slow. Looked rough but ran great. Sold that boat and motor 15 years or so ago.

 

[tphoyt]

Roadking
Using the old head gasket could be a problem. Once they are compressed is usually game over. Just a thought.

 

[Roadking57]

well gents the old girl aint got much. 30 psi only even after a shot of oil in cylinders. The old head gasket looks like someone tried to replace it but it never ran.
Almost looked new... I've ordered a powerhead gasket set and new head gasket as well. Also ordered a flex hone as well and it arrived already!
just need a set of orig size rings next.

 

[racerone]

Remove bypass covers and inspect rings.---Use small screw driver to push on them and see if they spring back / are loose in the grooves.----They may be jammed with carbon / corrosion.

 

[Roadking57]

Well new rings are on the way! Found them for 39 set.

But now my dang water heater has decided to give up the ghost and will require some attention. I have a tankless LP gas unit which has been awsome until now. 7 years into 10 yr warranty. Going to try a flow sensor and if that don't solve the problem I'll be replacing the entire unit.

Gaskets aren't here yet either, so I wait.

 

[Roadking57]

Okay! The gasket set is here but not the head gasket yet. I pulled the flywheel and the points were green. Third coil looks good. Pulled the fuel manifold off and reed valves are rusty on one side. Kinda odd. maybe engine was stored laying on one side? Putting all the hardware in separate little boxes and labeling everything. Still waiting on the rings.

Also the house water heater died even after I replaced a flow sensor Will
have to divert attention to that for a few days.

 

[racerone]

Rust on the reed valves would make me do a total tear down.------Opinions do vary on this approach !

 

[clemsonfor]

Rust on the reed valves would make me do a total tear down.------Opinions do vary on this approach !

I'm pretty sure that's his plan.

 

[Roadking57]

Yes Sir! Rings have arrived!!
Began removing powerhead.

Been working on the 73 in front of the shop. Moved her back to bench area next to the 70. Thats when I noticed the 70 is in fact that darker forrest green, and the 73 is that gold/green. both are faded quite a bit.

Ordered a new tankless water heater. Wont be here until monday. Until then I get to play with boat motors

 

[clemsonfor]

Yes Sir! Rings have arrived!!
Began removing powerhead.

Been working on the 73 in front of the shop. Moved her back to bench area next to the 70. Thats when I noticed the 70 is in fact that darker forrest green, and the 73 is that gold/green. both are faded quite a bit.

Ordered a new tankless water heater. Wont be here until monday. Until then I get to play with boat motors

Yikes , that's awhile without hot water!!