1956 25HP Johnson slips out of forward

[bethslave]

Hi, I've recently acquired a boat with a 25HP Johnson Seahorse [RD-19, if I read correctly]. From the research I've done so far, it seems to be a 1956 model. The motor starts easily and runs beatifully and will run all day in reverse or idle in neutral, but it won't stay in forward. If I hold the lever in place it will engage and run, but the moment I let go it slips into neutral. Does this sound like a major problem to fix? I hate to put too much effort or money into an older motor unless it is a fairly easy fix...<br /><br />Thanks for any help!

 

[petrolhead]

Re: 1956 25HP Johnson slips out of forward

Worn clutch dog? You'd probably need to open the gearcase to confirm it, and replace the dog if that's what it is.<br />If it's like my '58 18hp you may get away with turning the dog round, then it'll stay in forward but you'll need to hold it in reverse, but then how often do you run in reverse compared to forwards?

 

[WillyBWright]

Re: 1956 25HP Johnson slips out of forward

That'd be the problem. Turning the dog is about your only option. Unfortunately the mating surfaces of both the gear and dog wear, so chances are it won't help, at least not forever. You can't get those gears anymore.<br /><br />In my book, RD-19 is a 1957 35Hp. Same gearcase in either case. RD-17 is a 1955 25Hp and would be green. RD-18s are maroon and white 30s. RD-19s are also maroon and white. RD-19Cs are 1958 35s, I think they're white and gold and have a one-piece fiberglass hood. The older ones are metal clamshell hoods. Or would you call that a Bonnet in the UK?

 

[petrolhead]

Re: 1956 25HP Johnson slips out of forward

I'd call it a hood or a cowl, bonnets are on cars!<br />There is possibly another option to replacing the dog, and that is to re-machine the worn "ears", there's enough material there to remove a bit with a grinder and square them up again, same on the gears. <br />It's hardened steel, and the gear is harder than the dog, so it's more likely the dog has worn than the gear. I showed mine to a friend who's a better engineer than me, and he agreed that it should be OK to re-grind the ears, if I can't find a replacement dog for mine and it gives me trouble this is what I'll be trying.<br />Any decent machine shop ought to be able to do this very simple operation, and it would probably be way cheaper than buying a replacement dog.

 

[WillyBWright]

Re: 1956 25HP Johnson slips out of forward

You can grind new surfaces, but they won't have the surface hardening. So what, you'll be up and running at least. Problem is that the gear is so hard it is very difficult to machine. You'll need an abrasive, not your usual milling bit. You'd trash bits and the gear will be untouched.

 

[petrolhead]

Re: 1956 25HP Johnson slips out of forward

If neccessary surface hardening is easy to do as well!<br />I'd pull the lower unit, split the gearcase, and check out the dog first. If one side is good and the other isn't then turn it around, re-assemble and see how you get on, it should work fine in forward and will just need to be held in reverse, although at low revs it may not pop out of gear.<br />To do all this will cost you a couple of hours work, some gear lube, and maybe a gasket or two. At the same time you can check the gearcase for leaks and replace seals if neccessary, and also check the condition of the water pump.<br />If, when you have it apart, it all looks like far too much work you've lost nothing, and then you can sell it to some enthusiast who will take it away and turn it back into a brand new motor!

 

[boso]

Re: 1956 25HP Johnson slips out of forward

Hello guys,<br />Im reading all this post about clutch dog.Ihad the same problem with my Evin 18hp (1967).I agree with WillyBWright and petrolhead too. <br />It is clear that a hardened surfaces are hard too grid and we need some machine to do that, but if we grid the ears the surfaces hardenes will be the same because small parts like clutch dog are all made by hardened steel.

 

[bethslave]

Re: 1956 25HP Johnson slips out of forward

Thanks for all of the replies, I've got the lower unit in pieces in my garage right now and I've flipped the clutch dog. I'll post the results once I get it back together and test it. WillyBWright is correct that my motor is an RD-17, green 25 horse. I'm glad to know that the RD-19 gearcase is the same, I may actually be able to get my hands on one of those for parts...

 

[petrolhead]

Re: 1956 25HP Johnson slips out of forward

Now you've got it apart, does it look like the clutch dog ears are worn? How about the corresponding ones on the forward gear?

 

[bethslave]

Re: 1956 25HP Johnson slips out of forward

The clutch dog ears definitely showed wear, but I couldn't really see any on the gears. I put it all back together, filled the gearcase with oil, and found that it still won't stay in forward for the most part. I can get it to engage and stay in gear 1 out of about 20 times [instead of never, so there's a very slight improvement]. Reverse still works great, though reverse doesn't disengage unless I first move the lever to forward. Reverse didn't disengage before I took it apart either. Is there something else I should check or adjust, or is the lower gear set worn beyond hope? I'm shopping for parts on eBay...

 

[tgissel]

Re: 1956 25HP Johnson slips out of forward

Is this motor tiller handle or does it have remote throttle and shifter somewhere else in the boat? My RDE-19 performed this way a little till I adjusted the controls to get a more positive engagement of the shifter. Don't know if this helps or not. Good Luck.

 

[petrolhead]

Re: 1956 25HP Johnson slips out of forward

Have you tried adjusting the shift lever itself? It's held on with a pinch bolt that clamps it to a small shaft, but there's also a longer bolt that clamps it to a small quadrant behind the lever, the quadrant has slotted holes to allow adjustment.<br />Is there any play at the shift rod connector?

 

[bethslave]

Re: 1956 25HP Johnson slips out of forward

I've been on vacation [unfortunately without my boat] and have returned and finally had a chance to work with my motor some more. It turns out that my shift lever did indeed need adjustment. After a little trial and error, I seem to be getting positive engagement in forward every time. Thanks to everyone for the help and I'm hopefully off to the reservoir after church tomorrow to see how it runs!