1955 Johnson 25 electric start - Points problems?

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

Just out of curiousity, is that shift rod coupler behind the oval looking cover on the leg just before the lower unit? That brass piece connected to the rod that extends down to the lower unit? Sorry if my description is bad...

 

[HighTrim]

Re: 1955 Johnson 25 electric start - Points problems?

Yes that is it.

There is a detent in the rod. WHen you remove the bolt, the detent should be perfectly aligned with the hole before installing the bolt.

 

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

Im assuming Ill see this when I pop that cover off? Also, if it does turn out to be a bad clutch dog, if I drop the lower case that cradles the lower unit gears, is there anything I should look out for? To clarify, will these rods, driveshaft, perhaps other parts come falling out of the leg area? IF the dog turns out to be bad, I would much rather swap in the entire shaft assembly with clutch dog and all from my donor motor instead of disassembling all the different gear pieces.

 

[HighTrim]

Re: 1955 Johnson 25 electric start - Points problems?

Nope, have it upside down, take out the skeg screws, and nothing will fall out.

 

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

Well, I tore apart my 35 lower unit, to get a feel for it. Not too bad! Cant believe Ive been afraid to take these things apart! The gears and clutch dog in the 35 big twin look really good, except for they need some cleaning from water in the lower unit (ran for 15 minutes with water in it, not prolonged). I like the fact that I could swap out the entire prop shaft without ever unhooking the shift linkage... very convenient!

- shift linkage at the bottom of the lower unit, not the detent, lol

 

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

I suppose you experienced guys chuckle every time someone is afraid to take these lower units apart... Ill admit, even I thought there was some overly complicated method to these things.

The mystical lower unit, haha

 

[HighTrim]

Re: 1955 Johnson 25 electric start - Points problems?

The thought of gears, bearings, oils seals etc... could be intimidating for the first time. Once you do a few no biggie.

You will need new spaghetti seal and some sealer. I wouldnt reccomend reusing the old one. Coat the screws in the 3m847 as well before torquing. I tighten them in a spiralling fashion like you would a head, starting with half the torque, then final torque. Ensure the spaghetti seal end is cut square, not angled. There should be about 1/16" overhang so it buts up tight to the prop seal housing. You dont want it too long either so it bends.

 

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

ok, I appreciate the advice! I think I found the culprit... The gears at the end of the drive shaft were chewed up really bad. The dog actually looks good, but the gears definitely need to be swapped out. Other than that, I hope she' be running great by this afternoon!

 

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

it looks as if some dirt got into the bearings at the drive shaft, chipped away at the bearings and offset the gear so it was starting to skip and chip teeth. That's my novice opinion...

 

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

Heres a quick pic of the gear. Every tooth is chewed up like this!

 

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

Quick question... Are the skegs (term?) for 1957 big twin 35 and the 1955 25hp interchangeable as an entire assembly? Unfortunately, I cant use the gear from the 35 because it is set into bearings instead of having a separate bearing and race. If I can use the entire assembly, I could just transfer the good parts over

 

[HighTrim]

Re: 1955 Johnson 25 electric start - Points problems?

The 'skeg" is the fin shaped piece you removed to get at the gearset. They are not really supposed to be swapped, as they are cast as 1 with the gearcase. They are a matching set.

I believe as long as you swap out the whole prop shaft assembly, with pinion you are ok.

 

[HighTrim]

Re: 1955 Johnson 25 electric start - Points problems?



These should help, especially if you reseal your gearcase while it is opened up.

 

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

Second issue found... The fork that slides the clutch dog forward and back cannot attach to the housing. The mounting point is broken and appears to have been repaired with JB Weld that has since failed. Good thing I have plenty of donor parts!

 

[livinfulltilt]

Re: 1955 Johnson 25 electric start - Points problems?

Well, after taking it out on the water, everything worked great... Except the waterpump. Go figure.