Drive shaft fell out, 15 hp

[roscoe]

Helped my uncle change his impeller today. He says it was the original and I finally convinced him to change it.<br /><br />1985 15hp Johnson J15RECOB 20" shaft.<br /><br />Of course he had no manual, so we jumped right in.<br />All was going well until I grabbed the lower unit and put it on the workbench. Well the driveshaft plopped right out of the l/u. ??????<br /><br />Well we finished and put it all back together. Test ran it in a tank for 15 minutes. Checked lower unit oil. It still looks clear.<br /><br />I have no experience with Johnson lower units, but this sure seemed odd to me. Is the driveshaft supposed to be "free" like that? It seems like the water would be getting past the driveshaft seals and into the l/u. Or is there a socket for the driveshaft to fit into, and a seal below that?<br /><br />If thats the case, then could we...<br />get a shorter driveshaft and shiftshaft, remove the 5" mid-section, and have a short shaft motor?<br /><br />I had visions of an old SeaGull gearcase. A pint of oil, a cup of water, and an airpocket.

 

[The Marine Doctor]

Re: Drive shaft fell out, 15 hp

D/S seals just below the waterpump. Bottom of the D/S fits into the Pinion gear.<br /><br />As for making a long shaft short...NOPE...you can make a short shaft long though.<br /><br />TMD

 

[G DANE]

Re: Drive shaft fell out, 15 hp

Hi roscoe<br /><br />These driveshafts are only held by the impeller key and waterpump housing if you driveshaft has only splines on end, no thread. If it is threaded you have a nut floading areound somewhere. It is correct driveshaft can be pulled out and replaced with a short one. Changing the shift rod is more difficult, but can be done. Manual says to avoid pulling shaft up, in order not to damage the double shaft seal.

 

[The Marine Doctor]

Re: Drive shaft fell out, 15 hp

G Dane...if a short D/S and shift shaft are put in..is he to cut 5 inches off his leg?<br /><br />The only way for him to get a short shaft is if he has the long shaft "Kit" installed in the first place..then the extension of the leg can be removed.<br /><br />TMD

 

[roscoe]

Re: Drive shaft fell out, 15 hp

Thanks Doc and G Dane.<br /><br />The old impeller looked amazingly good for 18 years old, but it was barely dribbling from the telltale. Now it rivals a race horse.

 

[OBJ]

Re: Drive shaft fell out, 15 hp

Hey roscoe....all ya' need to make it a short shaft is the short drive shaft, short shift rod. Remove the extension piece and install the short D/s and shift rod. Ya' really need to get a service manual for the engine.

 

[roscoe]

Re: Drive shaft fell out, 15 hp

I had to remove the 5" leg extension to disconnect the shiftshaft joint. It appears that they only produced a short exhaust leg, then added the extension to produce the 20" leg. <br /><br />The question about converting was just for my curiosity. It seemed like it would be easy, buy maybe not cheap, as I'm sure the drive shaft is pricey. It seems almost too easy considering what others have had to do to make the change. I don't plan on converting it, as it isn't mine. And rest assured, if it was mine, I'd have a manual for it.