1957 Evinrude 18 clutch dog question

[runwfo]

My '57 Evinrude 18 recently started bucking intermittently like I was hitting something. After some research I pulled the lower unit to inspect the clutch dog. I found obvious wear on the clutch dog, but the gears look OK. The problem is my clutch dog (see pic) does not look like the PN 375711 listed for this motor. Not sure if the lower unit was rebuilt or replaced sometime in the past 60+ years.

Any idea what year model this clutch dog is from?

Is PN 375711 compatible with my gears?

 

[oldboat1]

Yours may be a 10hp model (e.g., 0329795). If that's what you have and intend to replace, I would see if the 10hp is a match and go with that.

 

[oldboat1]

Feel I should add a note to the above post. I know from experience certain 10 hp parts are interchangeable with certain 18s (’58 steering/carry brackets, for example). I cannot say, though, whether a 10 hp gearcase would be as robust as an 18 — assuming you may have a 10 hp gearcase, wholly or in part. The other and perhaps safer option is to find a ’57 18 hp lower unit to bolt on from a donor motor. You may, of course, have to replace the clutch dog on the donor unit….

 

[racerone]

A 57 10 HP lower unit looks the same as the 18 HP.-----It will fit.-------I do not believe the gears inside are the same.

 

[oldboat1]

Think he probably has a 10 hp lower unit, so would need the clutch dog for the 10 -- different from an 18. But while the 10hp clutch appears to be a direct replacement for the one he has, I don't know if his Fastwin will chew up the new one.

 

[runwfo]

Thanks for the info!! After some additional research, I think this may be a '58 lower unit. I have two 18 Evinrudes that I thought were '57s. They appear identical. I went to verify the model number and found the SN tag missing from the one I am working on. I checked the titles and one is a '57 (dog #375711) the other a '58 (dog #305191). I'm just trying to confirm the part I need to order. Mine is an 18 spline. I attached some measurements. If anyone can check the specs on a known #375711 or #305191) it would be GREATLY appreciated. One additional clue it the lower unit that may be a '58 has the pivot screw for the shift linkage. The other one does not.

 

[F_R]

I am holding a NOS 305191 in my hand. Counted the splines 3 times (hard to count those buggers). 19 splines. As for "Looks" it looks like the 375911 in your first post and not like the one with the calipers above.

I do know there were some spline changes in that era,

 

[oldboat1]

FYI: from a '58 10hp.

 

[F_R]

A 1958 10hp lower unit is very different than a 1957 18hp. Won't even bolt on as a complete unit.

 

[oldboat1]

Thinking it would be '58 to '58, presumably, according to post #6. But I don't know if the l.u. from a '58 10 will bolt up to a '58 18 (which he seems to have, times 2.) Anyway, was thinking runwfo might like to eyeball the 10hp dog to compare with the one he has. They look the same.

Nothing more to suggest here....

 

[racerone]

I believe the 58 model 10 HP started using the 5 1/2 and the 7 1/2 lower unit casting.----That will not bolt up to a 58 model 18 HP.

 

[runwfo]

I ordered the #375711 dog. Even though it looks different (no raised shoulders around the splines) it fit perfectly and shifts great. I haven't load tested it on the water yet, but expect the intermittent slip to be resolved. Seems that the design of the dog changed at some point, but they are compatible.

Thanks for the help!!

 

[oldboat1]

Interesting thread. Hope you post back after water testing -- sounds like you have it handled.