68 115hp Evinrude won't shift into fwd

[witenite0560]

So, I know forward is supposed to be the "failsafe" mode and I've got a pretty good idea from the books and schematics how the lower unit works. Mine will shift into Reverse and Neutral just fine, forward is another matter. At the beginning of the season, it was just a minor annoyance. It would take 10 or 15 seconds to shift to forward. But, it's progressively been getting worse. Was hoping to get through the season, but it started taking longer and longer. Monday my son and I were several miles up the lake and had been using a work around by leaving it in forward when we turned it off. It would start in forward. He hooked a fish while we trolling at idle and we were fairly close to some rocks, so instead of turning away from the rocks and making it difficult for him to keep his line away from the prop and such I instinctively shifted to reverse to give us some clearance.... oops! It would not go back into forward, despite everything I could think of doing. I disconnected the wires to the solenoids, just in case they were getting some stray voltage or something. I think one or both of them was sticking in the down position and keeping it in neutral (off the top of my head now I can't remember if it's both for reverse and one for neutral or the other way around) or something. I tried tapping on the side of the case to see if that would jar it loose, revving the motor slightly, etc. There was nobody else on the lake where we were and a pretty good breeze blowing against us. So, we tried paddling and were lucky to just hold position against the wind for a while. I tried reverse, but though reverse works for manuevering away from the dock and such, it really didn't make any headway, which kind of surprised me. Anyway, I was to the point of trying to find a place we could pull on shore and take off the lower unit to see if we couldn't find a stuck solenoid or something. It would have been difficult because one side of the lake is vertical cliffs and the other is a very steep, loose sand/gravel bank, probably in excess of 45 degrees. It was that or start hiking several miles over some very tough desert canyon country. My son was on leave from the Army and had to get back Tuesday, so I really needed to get him out. Well, I decided to try taking the lower unit off, used reverse to get us near shore, shifted to neutral as we got close and just to leave it in forward for good measure before turning it off I hit the forward button and Thank God! It shifted into forward. Ran like a champ all the way back to the trailer. So, I took the lower unit off yesterday and found the upper solenoid was a bit gummy, but don't know if it was enough to cause the problem. Also, looks like I need to replace the seals, as the oil was a bit milky. Yes, I do have the correct Premium blend in it, too. The thing I can't figure out is what pushes the shift rods back up when the solenoids are deenergized. I can't feel any pressure against them and don't see any springs on the schematics or anything, with the exception of the plunger spring that's in the end of the prop shaft and pushes against the shift dog, I think. Is it just hydraulic pressure against the shift balls that pushes the shift rods and solenoid plungers back up? I know I shouldn't have tried to make it through the season before looking into it, but hindsights 20/20. Any thoughts or knowledge would be helpful.

 

[F_R]

Re: 68 115hp Evinrude won't shift into fwd

If it is staying in neutral with the wires disconnected, the shifter piston is sticking in the oil pump or the solenoid plungers are sticking in the down position. You are correct, oil pressure is what raises them up, since the spring in the prop shaft is stronger than the weight of the plungers. But they should be loose and free enough to be lifted very easily. If the piston is sticking in the oil pump, it means complete disassembly. Hardly something you are going to do out on the lake. In fact you show guts by attempting to even remove the lower unit out there. I confess, that is not something I'd be considering or even have the tools with me to do. But I don't live in desert country either, and I carry a kicker motor.

EDIT: BTW, it can't be a 1968 115hp. Has to be a 1969 or...?

 

[witenite0560]

Re: 68 115hp Evinrude won't shift into fwd

Oops! You're right, the boat is a 68, the motor is a 70. I have a kicker that I recently bought. But, I'm in the process of overhauling the carbs and putting new seals in the lower end. Think I'll hurry that process along.
Fortunately, I always carry a tool kit in the boat. The 5/8" bolt in the center aft of the lower unit would have been a problem, since my biggest socket is a 1/2". But, as luck would have it, it wasn't torqued well. So, probably could have got it off with pliers. The 9/16" bolts would have come off with a crescent wrench. The rest would have been easy. Not to say going back together would have been a breeze though. But, considering where we were, I'd have tried it.
Ok, maybe you can help me clarify how this works. The manual and schematic are a bit vague in that area and I haven't completely disassembled one, yet. Does the oil pump plunger slide through the clutch dog and butt up against the thrust washer, which is butted against the forward gear? If that's the case, then the spring must be held in place by the clutch dog retainer and the pin that goes through the clutch dog and the hole shown in the prop shaft must be a slot that allows the clutch dog and retainer to move slightly fore and aft when pushed or released by the piston (or plunger, depending on which book you look at, since they use different names for the same part).
Hmmm, if that's the case, since I don't have the special tools to pull the snaprings that are deep in the unit, I may have to refer this problem to the shop.

 

[F_R]

Re: 68 115hp Evinrude won't shift into fwd

Oops! You're right, the boat is a 68, the motor is a 70. I have a kicker that I recently bought. But, I'm in the process of overhauling the carbs and putting new seals in the lower end. Think I'll hurry that process along.
Fortunately, I always carry a tool kit in the boat. The 5/8" bolt in the center aft of the lower unit would have been a problem, since my biggest socket is a 1/2". But, as luck would have it, it wasn't torqued well. So, probably could have got it off with pliers. The 9/16" bolts would have come off with a crescent wrench. The rest would have been easy. Not to say going back together would have been a breeze though. But, considering where we were, I'd have tried it.
Ok, maybe you can help me clarify how this works. The manual and schematic are a bit vague in that area and I haven't completely disassembled one, yet. Does the oil pump plunger slide through the clutch dog and butt up against the thrust washer, which is butted against the forward gear? If that's the case, then the spring must be held in place by the clutch dog retainer and the pin that goes through the clutch dog and the hole shown in the prop shaft must be a slot that allows the clutch dog and retainer to move slightly fore and aft when pushed or released by the piston (or plunger, depending on which book you look at, since they use different names for the same part).
Hmmm, if that's the case, since I don't have the special tools to pull the snaprings that are deep in the unit, I may have to refer this problem to the shop.

The spring goes in the prop shaft, then the clutch dog retainer with the hole aligned with the slot in the prop shaft. Then slide the dog onto the splines with the pin hole aligned with the slot. Use a suitable tool to push the retainer and spring back to where you can slip in the clutch dog pin. The dog now slides back and forth against spring pressure.

The thrust washer goes at the end of the splined area to have something for the prop thrust to push against. In turn, it seats into the forward gear.

The hydraulic piston slides back and forth in a precision bore in the oil pump, and pushes on the clutch dog retainer. Because it is a precision and close fit in the oil pump bore, dirt and grit and crap can make it stick. Worse, the dirt and crap usually imbeds itself in the soft aluminum bore of the pump and is difficult to remove. If you mess up the bore (oversize), it will bypass oil and not shift properly.

You are correct, there is a bear-trap strong snap ring way down in the case that takes a honker of a snap ring pliers with extensions.

 

[witenite0560]

Re: 68 115hp Evinrude won't shift into fwd

In case you're curious:

I pulled the lower unit, drained it and inspected everything I could get to. I did find some rubbery gunk in the bore of the top solenoid and there was some stuck to the plunger of the top solenoid, too. Cleaned it all off. Flushed the whole unit with solvent as much as I could and blew it out with compressed air.
Found that my water pump impeller had one vane broken off, so replaced it while I was in there, as well as the upper seal.
Put it all back together and pressure checked it. Checked good.

Reinstalled the lower unit, filled it with new Premium blend oil and checked it at idle on muffs. Worked like a champ, fwd, nuetral and reverse.
Took it to the lake Saturday evening and motored around just fine. Took it back out Sunday afternoon and it worked great, until.........
I decided to finally compare the two props I've got, both are 13x14. One has much broader blades with a curved trailing edge, the other narrower blades with a straight trailing edge. I had on the broader one and seemed like my rpms were a bit higher with no gain in speed than with the narrower one. But, I'd never had time to swap on the lake and compare. So, I beached her, swapped the props and checked. Sure enough, I get the same, if not slightly better speed with the narrower prop and rpm tops out at about 5100 - 5200. Seems to be a good cruise at about 20mph and 4100 rpm.
But, after I swapped props, it won't go into reverse! Almost does, you can hear and feel the clutch dog trying, but won't quite go. I'm going to try another flush. Thinking that I probably worked loose some stuff that had found a home in some of the nooks and crannies and hopefully I'll get it all out. If not, probably have to take it to my boat guy and have it disassembled and all that.
I've got another prop, but I need to get a convergence ring for it, it's a 11.5x17. What do you think the effect would be of installing it? I'd like to get my cruise rpm down just a couple hundred rpm, without losing any speed. But, would the loss in diameter make a wash of the gain in pitch? Of course, my other props are not new, so I doubt they're still really 13" in diameter anymore, either.

Ok, after thinking about the prop, please correct me if I'm wrong, but.... Since my WOT rpm should be (if I recall correctly) 5000 - 5500. Am I getting as good as I'm going to? Switching from a 14 to a 17 pitch will reduce my WOT rpm by 300 - 600, correct? (Not accounting for the drop in diameter, too.) Thoughts?