TOPIC: Slipping gear or Prop

What’s it sound and feel like when you spin prop by hand. I would think if gears are damage you may feel or hear something? Maybe clutch dog is rounded off? I don’t see attachment or know the motor type so just guess. Assuming you made sure shifter was fully engaged so shift rod was all the way down/up..

Sorry I left out that info. Motor is 1964 Evinrude 60HP. I tried to spin the prop by hand in both forward and reverse but I couldn't do it without using what I think would be excessive force. Spins easily in neutral naturally. I did check the shifter and it is fully engaging in both directions.

I think you will find the shift clutch & forward gear with rounded off clutch faces.

Right off the bat pull the lower drain plug on the gearcase and see if you have bright metal shavings coming out with the oil. That will tell us pretty quickly.
Secondly, just because the control goes fully into reverse and forwarrd does not mean the gearcase is. There are also adjustmments in that area and also the shift rod connector may not be properly installed.
Cbeck the gear oil first before we get into anything else. That's easy.

I checked and changed the gear oil, nothing unusual in the oil. I feel like I need a "Mechanic" buddy to help we work through stuff on the boat. Has anyone have any idea how to find someone with old motor experience? To make it more interesting I live in the Palm Springs area with a lake one hour away. I wish I could afford to just swap out the engine but that is not an option.

A stupid mistake I made a few summers ago which still haunts me.
Same issue you had but without the grinding. Put the boat in the water and it would back away from the dock without any issue. Shift forward and slow not a problem. Start to speed up and was ok and then the motor would rev without gaining any speed. Took the boat out of the water and thought I spun the prop. Took everything apart and found nothing unusual.
Turns out the motor was mounted too high on the transom and the prop would cavitate as soon as enough speed kept water away from the "bite" area. Really dumb move on my part but just to eliminate the possibility make sure your prop is in the water.

If you have a spare propeller, bring it to the lake.
Also, invest in a service manual for the engine. These are pretty simple engines to work on. As I mentioned before there are shift adjustments that need to be verified and adjusted if necessary.

There is actually an extension on the lower unit so cavitation shouldn't be occurring. Although it does sound like the problem that I am having.

Okay....I have asked you to bring a spare prop to the lake with you.
I have told you about the need for a service manual. They are sometimes available on Ebay
I have told you about shift adjustments that you can make at the engine.
To date you have not acknowledged any of these suggestions. There is no magic cure only a step by step evaluation and repair
Gearcases are plentiful for these engines should you need one and the 60hp was a real work horse of an engine.

Jezzz Pappy, I have been busy and haven't had time to deal with the boat! I have a shop manual, good point on the prop and I am going to start taking the lower unit apart as soon as i get A/C in my garage since it is currently 112 degrees here. Sorry I did not acknowledge your suggestions but I only pop on and off this forum.

I understand!
On a couple of different forums I try and help and give back some of what I have learned over the decades. Very often some of the basic steps are either ignored or simply not followed. Not knowing your capability all I can say is thanks for getting back and letting us know your situation.
I work in close to the same heat but with almost matching humidity so can certainly understand.
Keep us up to date when you can!

You have a long shaft engine, and it would appear it's sitting on a 15" (short shaft) transom. It's not gonna ventilate, but there will be a lot of drag and likely tons of spray.

A slipping propeller (or ventilation) causes an increase in rpm that's just about like a slipping clutch in a car. Rpm goes way up but no commensurate forward motion.

Slipping clutch dogs will feel like someone is hitting the transom with a big rubber mallet. And I'm not kidding on that, it's a quite startling thumping sound as the lower unit jumps in and out of gear. Once it's done that a few times, the clutch dog and likely forward gear are shot.

So there's 2 different issues to diagnose, plus the length on the transom.

If that motor came from the factory as a longshaft, it'd be a lot harder to convert. If it was done after-the-fact, it probably has extensions for the driveshaft, water tube, shift shaft, etc, and maybe can be re-converted into a short shaft.

First, thanks to all for the replies. This is getting my confidence up where I think I can actually do this.
About the long shaft, from the looks of the lower unit it is not factory, the paint is much more faded on one piece, So is there any advange / disadvantage to the longer lower unit? If I an taking it apart anyway I can certainly remove the extension piece.
Also, probably a stupid question. I have watch lots and lots of lower unit removal and disassemble, is it really as easy as it looks when the lower unit drops down? The Gear shift, water pump pipes just drop down too? They are not connected at the top?
I wish this was only a 10hp - it would be so much easier to deal with! Of course then I would not have a runabout!
I purchased this boat as a project boat, and it has turned out to be more project than boat but so far I am learning a lot and enjoying working on and improving the boat. Thanks again for any advise!

The advantage of the extension is when you have a short shaft motor and want to put it onto a 20" transom. If you have a shorter transom, about 15", then ditch the extension. keeping it on will only hurt the performance of the boat, cause more drag, consuming more fuel, and more risk of hitting something on the bottom in shallow water.

some times gear shift linkage is connected, and a cotter pin needs to be pulled. the ones I have dealt with that have something like this (force outboards) are just above the lower unit on the front side of the outboard, The older Mercs dont. I am not sure what yours requires. puling apart it should all drop down. sometimes the water tube pulls out of the water pump. You just have to line everything up when reinstalling it.

Add a 3rd reason to Ed's post above. Propeller hub slipping. Hopefully it is this simple. Sixty year old propellers are famous for hubs slipping.
Plus...we do not know if your gearcase has to be removed at this point. Disregard how a Merc or Force comes apart as yours is different. We will cross that bridge if and when we need to.

My 2 cents.
Dropping the lower unit is easy, putting it back is not so easy. Those water tubes need to be lined up perfectly to slip back in the rubber gromets. Best to leave then attached to the upper portion of the head unit but sometimes they do come out. When putting the lower back in you have to line up the drive shaft splines (turning the prop shaft by hand) plus the two cooling tubes, not always the easiest to do if you're working alone. If you can get the motor on an almost horizontal level it would be easier. I found that once you get the unit back in place with the drive shaft engaged you will have maybe an inch of space to maneuver the water tubes in place. a small stiff wire shaped like a hook is helpful to reach in there. Don't ask how many times I've had to lower a unit because the cooling lines slipped out of position.

Here is a link to a video of the problem: spaces.hightail.com/space/yG9zju0UPQ
The best view of the pop is 17 seconds in. I just found a hose attachment for the motor so I can test it out of the water at higher speed. I will try and get to this in the next week. I am in the Palm Springs area and it is 116 today so not happening today!
Thanks for all of the help.

Tried to view it but it will not open for me. Sorry.

I was able to view the video and yes indeed it is kicking. But it's at such a slow speed and rpm it gets me wondering if maybe it isn't just the engine kicking because you have the idle mixture too lean?

I would open up both idle mixture screws about 1/2 turn CCW and then see if it still kicks.

Normally, unless the shift clutch and fwd gear were really badly worn, it wouldn't be kicking out until you put a lot of stress/loading on the gearset, for example while giviing it a lot of throttle and attempting to plane out.

What it's doing there is just going along at a fast idle and kicking back. Which these will do if they're too lean. So try making the idle mix richer and see if that changes anything.

I will try and find another video. It did the same thing when I increased speed, just a kick or two and the engine revved up a bit but no increased thrust from the prop. It never sounded like grinding gears just a pop.

When you do get out on the water again and it starts doing it's thing look back at the shift handle on the side of the engine and see if it "kicks" at the same time the engine does. May be able to feel it at the shift handle on the control box as well. The more information the better!
You can probably also physically hold it in gear with the shift handle on the control box to verify or eliminate slipping out of gear as the issue.

Yeah, I've had that experience before, the handle will physically "jump" and if it does, that's a definitely symptom of kicking-out-of-gear. The shift clutch is actually riding over the cogs on Fwd gear. and being mechanically connected to the shift shaft via clutch fork, it's gonna have an effect right on the shift lever.

I just got the hose attachment so I can flush out the motor. Any chance it could push enough water that I could rev it up in gear to replicate the problem out of the water? Or am I just trying to avoid another falied trip to the lake....

I can understand trying to avoid another failed trip to the lake, I myself have had some issues getting my 80hp merc to run well. But that said, while running on muffs, you wont have the added forces of trying to move the water with the prop. in my experience, this will make the engine appear to be running better than it will while under load. IMO running on muffs is just to make sure she fires up ok and idles. You may still find it "kicks" and might be able to get a better idea where it is coming from out of the water. normally running on muffs cant hurt. just make sure you know your are getting water to pump through the motor to keep it cool.

So a few days later and I have made good progress with taking the lower unit apart. It has been a bit challenging, (who invented retaining rings anyway). My current challenge is removing the Shift Yoke. The shifter extension is still attached and the instructions that I see reference a port where I can detach it, but that port does not exist on my outboard. Does this pole screw in? There are to bolts on the top and bottom of the yoke but even if I could get them out I am not sure I could put them back in when I reassemble the gearcase. Any ideas?

There's a "window" on the Starboard (right) side of the center section, held on by 2 screws.

Once removed, you'll see the oval inner cover that must be removed to access the shift coupler bolt. 2 screws there, too.

Remove the fine-threaded bolt on the coupler and you'll be able to get the L/U separated from the center section.

Well, still no go with removing the Yoke. There is no window on the starboard side. I have the Clymer shop manual for 1.5 - 125 HP 1956-1972 but it seems to be too generic for my engine. I just ordered the exact shop manual for my motor and hopefully that will help. At least my library is growing!

OK, thanks for the pics, that clears things up a bit. I thought you were talking about the shift link that ties the upper and lower shift shafts together. Obviously you're way past that.

So you want to separate the upper and lower halves of the gearcase! 1st you'll need to pull the water pump and get it out of the way.

Directly behind and directly in front of the water pump housing, you'll see a big, fine-threaded locknut. There are long studs that go from the lower gearcase, thru the upper gearcase, and the studs & nuts (with a flat washer underneath) hold the 2 halves together.

So you'll need to undo those 2 nuts. Hopefully you have a fresh-water lower unit, the cases should come apart easily. It's a real bugger trying to take apart a Salty Dog, because those studs get locked-into the upper gearcase with salt deposits.

Referring to the attached diagram, let's go thru the high points:

The nuts are (77). The long studs are (81) and (82).

The O-ring that seals the upper and lower halves is (25). Best use something "sticky" to hold that in place, the O-ring is round and the groove it goes in is not!

Note the driveshaft bearing housing (61), it's held in with 4 screws. Replace the oil seal(s), also the gasket and O-ring there. The driveshaft bearing housing's gotta come off so you can pull the driveshaft out.

Note the shift shaft O-ring (68). You'll want to replace that. The bronze shift rod bushing (67) has to come out so you can get at the O-ring. This bushing is pressed into the gearcase. Some folks like to dig out the O-ring with a pick, but getting the new O-ring installed this way is really difficult and you can damage it. Best way is to pull the bushing and then you have ready access to the O-ring.

The way I pull this bushing is I take a 5/16" fine-threaded tap, and tap threads in it. Very easy to do, the tap is the perfect size to cut threads cleanly into the bronze. Once threaded, you can take a long 5/16-NF puller bolt and pull the bushing out of the gearcase.

2 ways to do that, one is to use a slide hammer. The other way which is pretty easy, is to put a chunk of angle iron or other stout material with a 3/8" hole (even a 2x4 would do if you have a long enough bolt) up against the flat machined surface of the gearcase, and with a flat washer under the puller-bolt's head, just screw the bolt down against the angle iron and let the natural pulling action yank it right out of the gearcase!

Once you're done replacing the O-ring, grease it with waterproof boat bearing grease or similar. Then slather some Permatex No. 3 Aviation-type non-hardening gasket dressing on the outside of the bushing, and drive it home.

One caveat on the O-ring replacement: once you've seated the O-ring in its cavity, run the greased end of the shift rod thru the O-ring. It's gonna be really tight, so work it thru carefully until all the way thru it. Wiggle the shaft around a bit to make sure the O-ring is properly seated. I've not done this before, and just pounded the bushing back in. Then, went to push the shift shaft thru and the O-ring was so squeezed-shut I couldn't get the shaft in. Had to mess around with it, very aggravating. Getting it all seated in place beforehand makes the job so much easier.

Note you can also use some OMC sealing compound or Mercury Perfect Seal on the shift bushing, O-ring, gaskets, nuts, studs, and bolts to help seal out salt & other deposits. They work as well as Permatex No. 3. This keeps things from binding up on the threads, and keeps salt/deposits out of metal-to-metal surfaces.

Useful Tip: With the driveshaft removed, and the case stud nuts off, you should be ready to separate the cases. Watch out for any loose needle or roller bearings coming from the split. One or the other of the pinion and driveshaft bearings (75, 76), IIRC, has loose rollers and you don't want any to get away from you!

Anyway, that should get you going! Post any other questions you may have as you get further into it.............ed

You have one pic that shows the gearcase rear stud, see the attached.

First, thanks for your reply. It is extremely helpful and I will start work again tomorrow!
Is sounds like the OMC Sealing Compound is different from the Permatex No. 3 is that correct? I am having trouble finding the OMC on line. It seems like I will have every thing taken apart by the time I finish. I think i need a bigger garage!

Yes the Permatex is different. The OMC stuff is much nicer to work with. Merc has a similar one.

To the best of my knowledge, both OMC & Mercury discontinued their gasket sealant compounds (both were similar & I used them interchangeably). They recommend PERMATEX 80017 or 80019. Only difference is the size of the container. 80017 is 16OZ, 80019 is 4 OZ.

jimandros wrote: To the best of my knowledge, both OMC & Mercury discontinued their gasket sealant compounds (both were similar & I used them interchangeably). They recommend PERMATEX 80017 or 80019. Only difference is the size of the container. 80017 is 16OZ, 80019 is 4 OZ.

Which is Permatex No. 3 Aviation-Type non-hardening gasket dressing.

A lot of auto parts stores carry the 4oz bottle-in-brush, and that goes a long way.

VersaChem Prime Seal gasket sealant is the NAPA brand of the type 3 Aviation. I agree 4 oz goes a long way.

Ed - are you going up to Tomahawk for the national antique outboard meet next week?

I see you can get the VersaChem in smaller tubes, too. I just ordered a 4 oz bottle of Permatex No. 3 from Amazon, after realizing that my own bottle was down to dregs! It ran around $11.00 plus tax, and that was the cheapest I could find. It sure has gone up! Just like everything else, unfortunately.

That Tomahawk boat show & outboard swap meet wasn't in my radar at all. Of course, it's a bit of a drive to Wisconsin from the PNW! And I just did a 1-1/2 month, 5500-mile trip to Alaska; got back at the end of June. No more traveling for me for a while!

The road trip up and down the AL-Can hiway was exhausting, with smoke, terrible roads, road work delays, you name it. Beautiful scenery along the way, though. We drove my Mom's new Maverick Hybrid PU and it got over 40mpg average, remarkable! I'd get one if they weren't made of Unobtanium.

Cheers...........ed

I understand! Thats the way I felt after going from Central Florida to Billings Montana and back on my motorcycle last year. 5800 miles in 11 days of riding. Gone 14 days but we did take a break here and there.

That's a lot of riding no matter how you cut it! Although I'd expect the Interstate hiways are probably a wee bit smoother than the AL-Can, eh!!

I did see quite a few riders up the AL-Can and gotta hand it to them, it takes some large Cojones to drive that road on a motorcycle. At least you can leap over all the potholes!!

Update and new issue. Well, after several days I finally have the entire lower unit taken apart. As everyone predicted the clutch dog and forward gear need to be replaced. Anticipating this I ordered the replacements and now I have a new problem. Apparently for my model they did a service bulletin modification to the clutch dog. I purchased the correct part # 312054 but it does not have the groove in the center of the part that the modification calls for. My drive shaft has been modified with the spring and balls and the old clutch dog has the groove but I can't find a replacement with the groove. Any ideas? I have attached pages about the service bulletin for your reference. Thanks as usual for all of your help.

Well, it is good that you have the spring-loaded shift clutch, that was an upgrade that OMC made because of all the problems with the Big Twins and V4s kicking out of gear. The spring in the driveshaft, pushing on 2 little ball bearings, helps the clutch "snap" in and out of engagement instead of the clutch dogs "slowly, gently" engaging the forward gear and causing excessive wear, if someone shifts too slowly.

BTW on this and most any other outboard, you should never "Ease it In Gear", you should give a quick snap of the wrist so it engages fast. The Big Mercs don't have as much of a problem with gear and clutch dog wear, because they use a stronger design. All these screwy electric/hydraulic gearboxes were OMC's way of band-aiding the problem when they should have totally redesigned their gearboxes.

Just like Karl Kiekhaefer's "Dockbusters" with NO clutch at all, constantly engaged gears and running the engine backwards for Reverse, was their great idea for the time! Well, it just caused another host of issues, hence the prominent "Full Gear Shift" decal on the 1st Big Mercs with FGS in the early 60's.

Anyway, back to your conundrum, I'm surprised that OMC didn't include a part number for the upgraded clutch in their bulletin.

I did check at Marineengine.com and the parts breakdown did include the old P/N, which supercedes to the 312054 clutch dog. Typically when a P/N is superceded, that means there is an improved part replacing it.

In the case of the 312054 clutch dog, that is certainly true. I checked a bunch of 'em for sale on eBay, and the pictures show that the grooves for the ball bearing/spring setup are present on both sides of the clutch.

So whoever you bought the new clutch from must have just had the old part number and relabled it. Sometimes that doesn't make a lot of difference and the old part works just as well, in this case you've got to have the right one.

You should send that one back for a refund and tell 'em why. It's not the right part.

As I was saying, eBay has a Ton of these and the seller whose dog clutch picture I'm posting was only $17 shipped. Better than $140.60 plus shipping at Marineengine.com !!

I can't post eBay links here, as this site parses them for some reason that makes absolutely no sense at all. So go to eBay and use this search string:

312054 (Clutch, Dog, Shifter)

I'm sure you'll be pleased with that!

And while I can't post links, I can certainly post the eBay item # of that $17 clutch:

394649414546

If you plug that into the eBay Search box, it'll come right up.

I saw some cheap forward gears, there, too. You might find a steal there and return the other $$$ one if you already received it.

HTH...............ed

Oh, Yeah, Brand New OMC forward gear, 377870, list at Marine Engine is over $305.00, eBay price $72 shipped!

Listing No. 391347374946

Another little secret:

1) Do you know what Forward gear is? It's a Reverse gear with a flanged bushing pressed into it.

2) Do you know what a Reverse gear is? It's a Forward gear without the pressed-in flanged bushing, and instead a floating bushing insert.

The trick in the old days was to find a good Reverse gear, because there was far less stress and wear put on them and usually no jumping-out-of-gear wear.

Then you just takes your press and presses out the old Fwd gear bushing, and presses it into the Reverse gear. Make sure the lubrication hole(s) line up.

Presto! "New" Forward gear. It's Magic!!

I think the later Reverse gears that came in Spring-Loaded clutch dog gearcases might have had the internal groove in them, too. If not, then it wouldn't be such a beneficial workaround. But in the Very Old Days when you were working with non-spring-loaded clutch dogs and they were jumping out of gear like mad, it was a good way to get it going again. Providing you had access to a good store of used parts. Which I did!! Lucky me!