25 Hp Johnson

[marcysibyll]

Made the trip to Oconomowoc,Wi and came back with a 1972 25 hp. No lower unit,but has elect. start and ele. choke. Put LU from my 18 Fast twin on it, shift lever works really soft- not like the one on my 72 20hp or the Fast Twin, but shift it does. Any ideas on making it firm, let me know. I plan on starting it on Sat. Will find out if ele start works. Will need the harness that plugs into the front of the engine, as if things are ok with it, it will be on the back of my Grumman and I'll put the 20 HP eBay Johnson up for sale.

 

[R.Johnson]

Re: 25 Hp Johnson

If you have a service manual, it will tell how to adjust the shift linkage up at the power head. The 25 HP gearcase has a spring loaded detent ball in the shift dog, the 18 HP does not have that, that is what probably makes it feel softer. The 18 HP gearcase will bolt right up with no problems, just adjust the linkage for full forward engagement of the shift dog. The only thing on the 18 HP gearcase is that it is a much lighter casting then the 25. You will find this with a caliper if you measure it in cross section. If you are going to sell the 20, put the 18 HP gearcase on that. All of these gearcases will interchange, and the 20 has the heavier casting.

 

[marcysibyll]

Re: 25 Hp Johnson

Thanks. I will do that- Swap lowers that is. The major prob with the sloppy shifting is that the springs were missing that go between lever and block. Took the ones off the donor Fast Twin and it's much better. I know that the 20 has a spring detent, as I had to replace missing pieces when I got it. <br /><br />Biggest prob now is a stripped spark plug hole. Got enough threads to hold plug in snugly, and will try to fire it tomorrow. Then head comes off and gets heli-coiled and loctite-ed.<br />Electric start works great- Where can I get the wire harness that plugs into the front of motor?

 

[marcysibyll]

Re: 25 Hp Johnson

Got the motor running today, but I think that starter solinoid is not long for this worls. Have carb to clean out, but it ran. Bottom cyl running rich( lots of sooty carbon on it). Pull flywheel and see what coils look like, also points and cond. <br /><br />Don't like fooling with carb, though. I'm not good at getting initial settings so the silly thing will atleast run. <br />If I keep it, I'll find a 20 or 25 HP lower unit and I'm still on the lookout for the plug and harness that plugs into the front of the motor with all elect. connections.<br /><br />Thanks for the opportunity of letting myself vent.