Whatsupwhatsup...I just accuired a '72 25hp Johnson, I know nothing about small boat motors. I know it takes 2 stroke and all that, It fires right up. The lower unit has a small crack in the housing, I have looked at semular motors online and it seems to be a common place for a crack to appear. I dont see a fill port to oil the lower unit, does anyone know if even takes oil, or if the oil in the fuel somehow lubes it. If anyone has any ideas or an old service manual hanging around let me know. I cant do a preflight inspection when I dont know what in the hell to look for.


Thanks in advance,




Joe

Don't know your motor exactly, but I would start with a 50:1 oil ratio. The bottle of two stroke oil will have a chart on the back that will tell you how much oil to put in so many gallons of gas. Get a good oil, not the cheapest you can find that is TC3 rated. Auto parts stores and Walmart will have it. There are two screws on the side of the lower unit for draining and adding oil. Drain from the bottom, take both screws out so it will drain faster, then add from the bottom hole as well, with the top screw out, until it comes out the top hole. Again, Auto parts and Walmart will have a hand pump that you attach to the lower unit oil bottle to pump it in from the lower hole until it comes out the top one. put the tip screw in first, the remove the pump from the bottom and put that screw in. Be sure to start the motor only when the lower unit is submerged past the cavitation plate. It is water cooled and the water impeller needs water to keep from ruining. If you don't know when the impeller was replaced, do it now. If it comes apart on you it will fill your motor with small parts of impeller that will be a costly repair. Replace it so you will know when it has been done and replace it every two years, or whenever your manual says. A manual can often be found on ebay or go to www.iboats.com. they sell them and parts for your motor as well. Good luck and let us know how the motor works out for you. Post a picture of you motor and we can post some better answers about your specific motor.

If lower unit is cracked youve got a problem need to have it looked at you need to talk to someone who knows motors

Listen to OPUS!!!!

A crack is an absolute No No, the lower unit must be ABSOLUTELY SEALED.....

The lower unit for that motor is VERY expensive...

I'm thinking the crack he is talking about is where the lower unit comes apart from the mid section. With pictures we could tell what crack he is talking about. Need pics of the motor and crack.

I know she looks ruff, but the price was right. It fires right up and under the cover looks in great shape.








IF this crack is a HUGE problem, whats the CHEAPEST way to "fix" it? And yes, buying a new lower unit is OUT of the question. There is a few Marine repair places out here, but they dont seem to be open on the weekends, which blows my mind!

Pics of the new paint job will follow.

Looks like corrosion to me. There is an area right above the cavitation and below the impeller housing that doesn't hold lower unit oil and water can get into and not be a problem, but not as much water as that will let in. I would clean it inside and out and remove as much corrosion as possible. It is cast aluminum so sanding would probably be the best. You might try a welder that can weld aluminum, but it may be too big for that. If that won't work, try some epoxy resin mix and lay a couple plies of glass completely around the lower unit so it won't "peel" away when water rushes around it. But it will have to be free of all corrosion and sanded well for the epoxy to stick to the cast aluminum. And there are no guarantees that will work. If it will hold lower unit oil without running out that is the only way I see to fix it without buying a new lower unit housing.

I was restoring a motor like that and by watching ebay I was able to get a powerhead for $25 to the door and a couple weeks later a lower unit for $18. I rebuilt the entire motor for about $200, including all new ignition, reeds, 2 new props, and all the OMC special tools needed to work on it.

TIP: lots of rednecks have a deathly hard time spelling Evinrude (and yes, sometimes even Johnson) even though the word is SCREAMING at them from the motor cowl. Some people don't respect their nation enough to bother learning to use the language properly. Sure, it's bad for our national dignity, but good for the savvy buyer. By searching for common misspellings (Evenrude, etc.) of what you're looking for on ebay or Craigslist, you can clean up like a big dog.

I scored a buddy a replacement engine for his Lexus on ebay for $35, and it's still running great 2 years later. The total for the engine swap was about $150, with most of the expense being Fat Tire Ale. The shop wanted over $4000 for the job. The idiot seller listed the engine as coming from a "Lexis", so nobody bid on it but me. LMAO! We used my engine lift and stand that I got ebay for $40 for both, local pickup.

With old gear, if you're patient and shrewd, you can tend to repairs for chump change. Housings for that lower unit pop up pretty often for cheap. Good luck with your motor, and don't run her unless she's 100% sealed. Those are great motors if treated halfway right.

You might be able to go on-line and download the manual for that motor from OMC.

Worth a try....

The motor uses 50 to 1 ratio oil. The crack is below the water impeller. Tried to fix the neighbors and it did not work. I do have a bare housing for 25.00

I would take him up on the housing for 25 bucks. With a manual, you can put your parts in it and be off to the races. On ebay there is a guy that has manuals on CD's fairly cheap.