Is this clutch dog the right way around? Which groove is groovy? (Johnson 55HP)

Hi Folks.

I have a Johnson 55HP from 1980 (engine model 55EL80C).

Im putting the lower unit back together and being a bit paranoid about whether I have the clutch dog the right way around.

The service manual says "Install clutch dog on shaft, grooved end on dog facing forward end of shaft".

I was a bit unclear what 'grooved end' refered to here as I see it as being one of two meanings:

1) The grooves that are found all inside the dog (to fit onto teeth of prop shaft) which then extend on only one side of the teeth. Eg this:



OR

2) The thin groove that goes around the whole outside of the dog itself, Eg this:



I'm pretty sure that the "groove" is what I describe in 1) above, mainly because only some dogs seem to have the groove described in 2). So I assembled is this way so far but I would love a confirmation someone who has done more than one of these units to put my paranoia to rest!

To make me more confused.. the manual has the illustration below which points to a groove quite vaugly towards the middle, so a bit baffled what that arrow is supposed to be pointing to!

The grooves used to be cut into the face of the shifter dogs when grooves were mentioned... apparently many boater mechanics missed that and the result would be jumping out of gear with brand new parts, even when all else was as it should be.

The "groove", in your case, would be the outside one running the entire circumference of the shifter dog.

There is also (usually) an imprint on the other end of the dog that states "Prop End".

No doubt about it.-----The maual is correct again.------That groove on the outside is to be on the forward side.----Factory replacement parts would have the groove.----Not sure about aftermarket parts.

Thanks a lot for the help guys appreciate it.

@joereeves re:

The "groove", in your case, would be the outside one running the entire circumference of the shifter dog.

Click to expand...

Thanks, that wasnt what I understood so good you clarified that. Just to be sure, you mean the one in the picture I posted under number 2) above right?

So in which case it would imply the way I have it set up now as below is correct below, is that right?




@racerone

Factory replacement parts would have the groove

Click to expand...

makes sense. What threw me here is that I have another clutch dog that the owner left for me which is certainly an original as it has the OMC stamp, however this doesnt have the groove but instead have 'prop end' (as Joe mentioned) which I supposed negates the need for the groove in which case.

Either way i think I have this the correct way round now! Thanks a million again for the help.

In my opinion that is NOT CORRECT the way it is assembled now.------Likely be taking one apart tomorrow and will confirm how they are put together if you like.

eek! Ok thanks @racerone yes that would be very helpful ill try hold fire going to far along with this until tomorrow till I hear back! Much appreciated.

@joereeves whats your opinion. Seems if I understood you think this is the right way from my last image above?

My thinking (for what its worth certainly no expert!) is it seems correct. I say this for one main reason that if I look at the other original part pictured below, this has an OMC stamp on it (so seems original) and it shows 'prop end' written on one side. Then when I compare this original dog to the one I am installing if I put the two side by side to ensure the teeth grooves (seen in picture 1 I posted earlier) go on the same side, then this suggests its right.

I might have taken a photo when I took it off so ill try dig that out also.

Why not put it together as shown in the manual.----Groove to the front !!

It turns out I took a photo of this as I dissasembled it which you can see below.


Before disssembling:


This dog as you see has no groove on the outside circumference however as with all these dogs (I have 3 of them to compare) they all have only one side that has grooved teeth on the inside. These grooved teeth on the dog shown are on the side with the part number, so the way I have it set up in the image above.

Its a little odd as like you say racerone the manual does say "Install clutch dog on shaft, grooved end on dog facing forward end of shaft" however the new part is an aftermarket part (part REC319895) so im not sure I trust that groove.

Am I right to say that the difference between being one way around or another is basically that one side has the grooved teeth extending longer on one inside? If that the only key difference then the way I have it round is very likely correct since

1) The original OMC part confirms that since it shows 'prop side' in writing an I can compare it
2) It lines up with how the part was when it was dissaembled (could have been fitted wrong I suppose).

To summarise, is the main difference between being one way round or another about these teeth below which only show on one side?

jasondainter said:

@joereeves whats your opinion. Seems if I understood you think this is the right way from my last image above?

Click to expand...

I was merely pointing out what groove was being spoken of... NOT... which way it should be facing as I assumed that when the manual states... "Install clutch dog on shaft, grooved end on dog facing forward end of shaft", that you were aware of which gear is forward gear?

The gear attached to the propshaft is Forward Gear... The Groove needs to be facing Forward Gear! You need to tun the dog around so that the Groove is closest to that Forward Gear.

This photo explains what I mean a bit better below:

So if I follow the groove on this aftermarket part i am fitting, and as you both say swap it around so that the groove faces the forward gear (opposite to how I have it now) what that means is the 'grooved teeth' on the inside on the side where they extend longer will be

1) Opposite to how it was when I took it off

and

2) Opposite to the original OMC part pictured above.

I'm happy to take your word for it if you think this is right (hell you know more than me here!) but this is an aftermarket part and I'm a bit worried about that.

Is the inside grooved teeth and which side has those teeth extending longer important?

jasondainter said:

This photo explains what I mean a bit better below:

Click to expand...

On that photo above shows what I mentioned....... Imprinted right on the dog is the words "Prop End"!

@joe I think you misunderstood above is an old part I am not fitting (its all rounded off). I took that photo myself a few minutes ago.

The reason I posted this photo is becuase you see here the OMC part shows the end facing prop as the SAME end with no grooved teeth on those 3 teeth showing in the photo.

On my RECMAR new part I am fitting, if you fitted it with the circumference groove per the manual as I believe you and racerone are saying to, it would NOT have those teeth as per the original and would be the opposite.

So on my aftermarket part, I either trust the groove, or I trust the side the grooved teeth as longer on.

Are those grooved teeth where one side has them going all the way down the teeth significant?

Trying my best to explain what I mean, sorry if its not making sense.

Yeah... Sort of confusing. I think it's got to do with comparing "splines" with "grooves"... however, no big deal!

Ignore the splines that coincide with the splines on the propshaft.... concentrate on the word "groove" which is singular.

The groove that you will encounter and is most common is actually cut into the face of the shifter dog(s). <-- In this case that I speak of here the grooves (plural) would be in the extreme end as if one was looking directly through the splined hole of the dog.

In your case, the manual states "groove" and pictures same as one groove NOT on the face or rear portion of the dog, BUT on the actual side surface of the dog's outer circumference. This is what racerone and I state the manual is speaking of which should be facing and closest to the forward gear.

Hopefully this clears up the confusing confusion.

Hey Joe.

I dont think I'm explaining my question very well, apologies and let me try again.

Every clutch dog I have seen for my model (3 in my lifetime!, 1 original and 2 aftermarket) they all have a common characteristic that only one side has splines going all the way across the teeth. Here you see it pictured below on one of mine showing on the inside there where it says "spline" these splines go all the way to the end. On the other side however there are no splines on those teeth, in other words the splines dont go all the way.



I wanted to know if the side with the splines going all the way ways always supposed to be in one direction or whether it makes no difference. It would seem strange to me this isnt supposed to always be consistent.

This (which side has splines going all the way or not) is the only thing I could see by eye that makes turning the thing around make any difference at all.

So to summarise my questions are

1) Does the end that has a longer inside spline need to be a certain way round or does it make no difference
2) If it makes no difference on above, then what is the main difference in turning the unit around, what difference does that make?

Yes, I know exactly what you're speaking of... the splines extending out more-so on one end than the other... and i am telling you to ignore that fact as that does not determine how to install the shifter dog... the manual instructions about the groove does.

Whichever way those splines face when the dog is installed properly is fine with me.

I'm well aware that any clutch shifter dog can be installed backwards, in either direction... and believe me, it does make a difference. Those "forward" dog lobes are machined to grab in one direction only. It is a small difference, one that cannot be judged by eye... BUT... it is there, and they need to face forward gear.

Install it with that groove facing the wrong direction and I guarantee it'll jump out of gear.

Every so often a boater will notice something about a component which serves no purpose and jump to some conclusion that it appears to demand a explanation... and they just can't let go of it. Those splines seem to have dropped anchor on you. Perhaps the shorter length on one end have something to do with holding the component in its final machining, I don't really know.... but I know why that groove's there.

Hi Joe.

You sir are a legend! Thank you so much for explaining that it was exactly what I wanted to know!

You are quite right, once you said that I took a closer look at the dog lobes and you can actually notice the very slight angle difference on those (very small but put the one way round and as you say it wouldnt grip as well).

Every so often a boater will notice something about a component which serves no purpose and jump to some conclusion that it appears to demand a explanation... and they just can't let go of it

Click to expand...

Haha... yes 100% guilty there! But now you explained the difference witht the lobes it makes way more sense. I just couldnt see the difference before!

I will put my spline obsession to bed and have swapped the dog around now with groove facing the forward gear.

Thanks a lot to you and @racerone on the help on this one!

You're welcome my friend.... So glad we could come to terms avoiding fisticuffs here, and so ends the saga of the spinney dog.

I had to say something here, Jason. This is a detail that could really screw you up, the supposition that the internal splines are more important than the "markings", could fool many, including yours truly. I have been known to successfully dress these dogs for extending their useful life. The angle HAS TO BE 90 degrees or error only a couple degrees to "holding" into engagement. If its the other way, it wont work and "jump out" to neutral under power. Why they don't do a 90 degree in both directions, who's to guess???? Perhaps so you can't "flip it around" like in the old days......gotta buy a new dog. Woof, woof!

If your going to dress dogs you have to do gear ramps also. I have a machinist do my hard to find and pricey gears. The trick is to remove equal amounts from dog face and leave a 3°angle and do the same to gear ramps or load wont be distributed across gear face..

Excellent info, Pappy. I have tried sometimes and failed as you might know. It's already broken, so I have experimented. What you got to loose but a little time? Win some, loose some. I also give the guy a 1 year warranty, but the deal is, they get a lesson in proper shifting procedure.

Hi Folks.

So a few years on... I would love to resurrect this thread as there were some developments.

The assembly I went with above did not seem to be correct.

The dog was slipping over the years and eventually got to the point where reverse and forwards both slip badly.

I took it off, and took this video where I look through 4 different dogs (one being the original).

I know some very smart people (way more experienced than me) have commented on this already but I'd like to propose a few things...

1) That the splines inside the dog do in fact matter. In 4 cases so far I have found this to line up with that theory. This could be a massive co-incidence, please prove me wrong, but I've also found pictures online of other dogs and every single time its the same thing, splines on the inside facing forwards (away from prop end). I believe this is a good way to double check if the dog is the right way around. Prove me wrong!

2) That the hole where the pin goes into the dog and where it lines up with the (3) teeth of the dog is significant. Against, i know I know this Isn't supposed to matter. but watch the video and tell me I'm wrong if all 4 dogs follow this pattern. Then the one time I break that pattern, it slips out of gear.

Find me evidence of one dog that follows the installation on these models with internal splines going to the prop end, and I'll gladly eat my words and concede to ignorance here, but I just don't think I'm wrong here.

By the way, when I propose that 1) and 2) matters, I specifically mean for this specific engine (1979 55hp electric start). But for my engine everything I have seen points to this being the case.