1973 johnson 25hp 25R73A

[clemsonfor]

Resealing the lower unit on the same motor right now. Put new gears and stuff in it. Having to put the old style bearing in there because I bought a NOS type gear so it won't work with the roller bearings

 

[Roadking57]

Spent the afternoon working on the buildup! My Queen even helped! Those dots on her neck are honing oil splatters Yes, She can turn a wrench! Got the upper crankshaft seal replaced. Added assembly lube to the bearings. Next step is installing the crankcase cover.

 

[Roadking57]

Well I found out why the pistons looked like the engine was ran hot

 

[racerone]

Doubt that impeller was the reason for overheating.-----Looks like it might be new.------The old one is what you want to look at.

 

[Roadking57]

That is the old one. Been in it since it ran last over ten years ago.

I disassembled the gears. Someone lost the dog clutch spring and both balls.
found a part number for an older rude 316505/6. Hope they fit. Gears look good no wear marks, bearings feel good.

 

[racerone]

I am just a dummy.-----That pump housing looks new to me.----I should step aside on this project.

 

[Roadking57]

You are no dummy Sir, The housing may not be original. The P.O. said He replaced the impeller once or twice in the years His Dad owned the motor. He cant remember who else may have worked on it. He had 2 older brothers that used it during that time, all 3 were shade tree mechanics.

 

[Roadking57]

Well I talked to the fella I got the '70 from and He tells me "Oh yeah, I put a new impeller in it last time and maybe ran it once. New housing and all." Still was 10 years ago. I don't trust it. Got a new one anyway. Just waiting on little spring to arrive to put prop shaft and gears back together. My 50ft roll of lower gear case seal has arrived, and, The new balls are here but I haven't tried fitting them yet. Still waiting on points & condenser set, and charging coil. The rectifier made it here too.

 

[Roadking57]

Question
Would brown permatex be good enough for the crankcase to powerhead ?
Or do I need to buy some of that ultra black stuff?

 

[jimmbo]

I really don't like the idea of using a Flex Hone on 2 Strokes, as the balls can mess with the Ports. Rigid Hones can also reveal Wear, by not contacting the Worn Areas.

As for the Impeller, I suspect the previous Installer was wiggling the Driveshaft back and forth, instead of turning it Clockwise continuously. A bit of Soap or Waterbased Lube like KY, will make it easier to install a new one. Don't use Oil or Grease as it can affect the Impeller Material

 

[racerone]

Do not use any RTV type sealer anywhere on that motor.----Use BRP gelseal on crankcase to block ---metal to metal ----joint.

 

[Roadking57]

Loctite 518 ?

 

[Roadking57]

When I do a search for BRP gelseal thats what comes up.

 

[clemsonfor]

Well I found out why the pistons looked like the engine was ran hot

I don't think one vane going the wrong way would make the engine overheat. It would create an OD or pulsing water flow as one vane would not be pushing water but I think it would still cool the engine unless many things went wrong.

 

[racerone]

One of these days I think I will put a pump together with EVERY vane the wrong way.------Start it , run it at full throttle for 30 seconds and see what happened to the vanes