1970 25 hp Evinrude outboard

[bjbmedic]

I recently purchased a boat with a 1970 Evinrude 25hp outboard on it and the last 2 times I had the boat out I noticed that the gears seem to have some sort of a slip in them and I have not been able to figure out why. I will seem to slip out of gear when I open the throttle much more than idle and at times will not even go into gear at all. I pulled the lower unit off and opened the gear case to see if there are any parts that look worn or bad but the gearing looks new. If anyone has any idea as to what this could be much appreciated. I did notice that one of the times it was doing this and wouldn't go into gear that I found the pin in the prop had been broken. Thanks
Brennan

 

[samo_ott]

Re: 1970 25 hp Evinrude outboard

Does it pop out and seem like you're hitting a log? Usually that's the way it comes out. Usually it is a worn clutch dog in the lower unit. Are you sure you looked at it closely? Can you post pics of the gears? Also there's an adjustment on the shift handle that might help with the shifting.

 

[F_R]

Re: 1970 25 hp Evinrude outboard

If it is actually coming out or gear, it is either a worn out clutch dog and forward gear, OR the shift linkage is worn out, OR both.

OR, needless to say a busted shear pin.

OR it it mechanically stays in gear but slips like spinning your wheels on ice, the propeller hub is slipping.

Here is an extremely worn out clutch dog: (They will pop out of gear way long before they get this bad.)

 

[bjbmedic]

Re: 1970 25 hp Evinrude outboard

To describe it it feels like I am hitting a log. I figure I broke the shear pin with the jerking it caused. I havent put much of a load on the motor since it first happened so I am hoping that the forward gear is still good and its just the clutch dog. I will try and post a photo tomorrow if I get a chance. Thanks
B

 

[samo_ott]

Re: 1970 25 hp Evinrude outboard

If it's like hitting a log, it quite probably the clutch dog. Each time it pops out you're doing damage. Keep it slow where it doesn't pop out and you're ok... But you will need to address the problem unless you're ok with low speed and minimum load.

 

[bjbmedic]

Re: 1970 25 hp Evinrude outboard

Well I got the gear case apart and there is a little wear on the clutch dog but Im not sure if it is enough to make it bad or not. I dont think the gears look damaged either but Im not sure. I will have one of the local marinas look at the parts and let me know if they are bad. I did notice that there was a thrust washer missing between the clutch dog and the forward gears. What kind of problems might that cause me to have?

 

[samo_ott]

Re: 1970 25 hp Evinrude outboard

Can you post pics of the clutch dog and gears?

 

[dew2]

Re: 1970 25 hp Evinrude outboard

Well I got the gear case apart and there is a little wear on the clutch dog but Im not sure if it is enough to make it bad or not. I dont think the gears look damaged either but Im not sure. I will have one of the local marinas look at the parts and let me know if they are bad. I did notice that there was a thrust washer missing between the clutch dog and the forward gears. What kind of problems might that cause me to have?

I have 2 lower units from a 1975 25HP. I also noticed both have no thrust washer on the reverse gear,I dont believe either has ever been opened.

 

[bjbmedic]

Re: 1970 25 hp Evinrude outboard

Ok here are some pictures of the clutch dog and the forward gear. there are a couple small wear spots on the dog and and a very slight one on the forward gear. Hopefully these are good enough for you to see what you need to see. My camera isnt the best but I could try to make better ones if this doesnt work. Thanks.
B

 

[bjbmedic]

Re: 1970 25 hp Evinrude outboard

next 3 pictures are here
B

 

[samo_ott]

Re: 1970 25 hp Evinrude outboard

Huh. They don't look too bad. I'd reuse em if they were mine.

 

[bjbmedic]

Re: 1970 25 hp Evinrude outboard

Could the missing thrust washer cause a problem with it coming out of gear. I have no idea. I didnt think they looked very bad either so I have no real explaination for why its coming out of gear. Could it have something to do the shift arm maybe? Any ideas Im open too. Im hoping to avoid having to take it to someone cause I dont wnat to pay some one for something I can do my self if I can figure out what part is bad. Thanks
B

 

[78 mckee]

Re: 1970 25 hp Evinrude outboard

Check the forward bearing for excessive wear. This will also cause the clutch dog to pop out under load.

Gary

 

[bjbmedic]

Re: 1970 25 hp Evinrude outboard

Bearing looks fine too. I wonder if this is the problem?

 

[dew2]

Re: 1970 25 hp Evinrude outboard

If your talking about the offset bend 2 of them,I have 2 cases apart now and both have the identical offset bends. The condition of the clutch dog and gear look good! I'd start looking at the shaft legnth adjustment.

 

[bjbmedic]

Re: 1970 25 hp Evinrude outboard

Could you explain the shaft length adjustment to me. I noticed that from the manuals I have the shaft is straight in all of them so I though maybe the bend you can see is from some sort of damage that prevents the gear from being pushed all the way into place and thus cause the slip. I ordered a new shaft since i could get it really cheap. I will be curious to see if it has the bend this one has
B

 

[bjbmedic]

Re: 1970 25 hp Evinrude outboard

dew2, do you mean the adjustment thats by the shift lever on the motor or is there something along the shaft that you are talking about? I should receive my new shift arm this week so I wont be trying to do anything until that comes in. Thanks
B

 

[dew2]

Re: 1970 25 hp Evinrude outboard

Yes I'm working on a 1975 Johnson 25 and the shift arm placement I believe will shorten or legnthen the shift rod making the clutch dog travel either to the forward or reverse.With out looking right now, if you need the dog to travel more to forward the shift arm would removed and placed more toward reverse then tigthened.I'm sure some where there are instructions.Do you have a manual? I work off a wide spectrum manual,it is for like 1970 something to 1989 or so from small HPs to 35,again without it infront of me I'm not sure but close.
If you have problems PM me,If a post isnt up top I dont search. I will look at mine better just got some 3M 847 sealer and will assemble the two lower units I have and see whats up.
Go here and look at lower unit group.Then look at part #39
http://shop2.evinrude.com/Index.aspx?s1=p8ep1jmbfj5rmh5np47sk6vpc1&catalog_id=0&siteid=1

 

[bjbmedic]

Re: 1970 25 hp Evinrude outboard

Well my new shift arm came and it is bent just like the one I had so I guess that isnt the problem so I am guessing it has to do with the adjustment. In the manual the only thing I can find about adjusting the shift arm has to do with the shifter at the top of the motor so I will be trying that unless there is another adjustment that someone can tell me about that I cant find. On another subject, does anyone know where you can get test props at? I cant seem to find one and I am curious how much it would cost to get one. I am getting a barrel to test in on Monday. Thanks in advance
B

 

[dew2]

Re: 1970 25 hp Evinrude outboard

In the manual the only thing I can find about adjusting the shift arm has to do with the shifter at the top of the motor so I will be trying that unless there is another adjustment that someone can tell me about that I cant find. B

Thats the only shift shaft adjustment,A prop is really fair priced right here at Iboats, check out the Solas props. Its been to cold to heat my garage so I haven't had a chance to do the shift rod adjust just yet.If you do it and figure it out let me know,Its probable pretty simple?????? Once its looked at.