1974 Mercury 85 - Stuck in reverse

[tlzimmerman]

Just bought a 1978 glastron with an 85 hp 74 mercury on the back. The boat is an original one owner. Motor runs, but its stuck in reverse.

I undid the shift cables just to make sure everything is free, and it is, did it back up, and it just won't come out of reverse. All the linkage is free to when it turns and runs down into the bottom end.

I am a relative newbie to working on outboards, and the little experience i do have is with johhnyrude stuff. Whats it take to drop the bottom end off one of these to replace an impeller? I know on our evinrude I have to disconnect some linkage, but I am not seeing how to do that on this engine.....do you just undo the bolts and drop the bottom end out?

Is it a common problem that these engines get stuck in reverse? Any clues as to what is wrong? Should I just haul it to a boat shop and have it done?

Any opinions or information is greatly appreciated. For its age, this engine is in incredible shape (always stored inside) and they said it was completely rebuilt in the early 90's. But I have no idea if this is a simple problem or something much more serious.

Thanks in advance.

Thomas

 

[bktheking]

Re: 1974 Mercury 85 - Stuck in reverse

Could be that the lower wasn't but back on properly, many of these merc's have a splined shiftrod, the rod rotates as opposed to move up and down. On that motor probably 3 bolts holding the lower on, front back and trim tab.
If the splines aren't mated perfectly (synched if you will) when it's put back together they will be stuck in reverse.

 

[King James]

Re: 1974 Mercury 85 - Stuck in reverse

drop lower unit put in new impeller since your there check check bushing assembly on shift shaft spin that to neutral lower unit should spin with out drive shaft spinning now click into forward it should now spin drive shaft put back into neutral put put shifter into neutral and remove cable then place a pair of thin six inch needle nose vise grips on shift shaft as close to bushing as possibe carefully slide unit back into place this can be tricky trying to get coolent pipe and drive shaft spline and shift spline to line up grabing a friend who can help manual turn flywheel is great help once shift spline is in remove vise grips almost just not enough room to do this just so you know you will also need to install mid shaft nuts on studs prior to completly getting lower unit all the way up some reason there is not enough room once you can get those nuts started use them to pull lower unit up check to see that you are still in neutral if so bolt rest of lower unit up now adjust shif cable to line up with shift lever on motor NEVER SHIFT GEARS WITH OUT MOTOR RUNNING NEVER RUN MOTOR WITH OUT WATER YOU CAN SNAP REVERSE SAFTY LOCK EASY AND IMPELLOR WILL MELT IN SIX SPINS OF THE STARTER Im no master boat mechanic but i service six mecurys 12 johnnyrudes for friends and family on my lake this is how i do it and it works hope it helps james

 

[King James]

Re: 1974 Mercury 85 - Stuck in reverse

i would also check neutral saftey switch motor should not turn over in reverse ever

 

[tlzimmerman]

Re: 1974 Mercury 85 - Stuck in reverse

Thanks for the thoughts guys. Am I correct in hearing that I don't have to unhook any linkage before I drop the lower end?

 

[bktheking]

Re: 1974 Mercury 85 - Stuck in reverse

You don't have to undo any linkage.

 

[Chris1956]

Re: 1974 Mercury 85 - Stuck in reverse

James, The neutral safety switch is in the MerControl. It is likely that the upper and lower shift shafts are misaligned.

Thomas, That motor has 5 nylon lock nuts and a bolt holding the gearcase on. The bolt is under the zinc anode. The zinc anode unbolts using a thinwall 1/2" socket thru the hole above the zinc anode.

Drop the gearcase, turn the lower shift rod CW until it clicks into neutral. Set the Mercontrol to neutral, replace the waterpump impeller, gaskets and wearplate, grease the drivesahft and shift splines and carefully mate the gearcase to the midsection. You will need to turn the flywheel with your hand to align the driveshaft splines.

 

[tlzimmerman]

Re: 1974 Mercury 85 - Stuck in reverse

Chris...thanks I have found everything you say. I am confident at dropping the bottom end now and at least checking things out, which is a long ways from where I was.

I have my doubts of just dropping it and being able to click it into neutral, I think something is locked in the gearcase. What you guys are describing sounds like an alignment problem, and this is not an alignment problem. He had the control and linkage all disconnected, I hooked it all back up and its just flat stuck, the control is in the right place (reverse) and won't budge back forward into neutral. I also tried to move the lever where the shift cable hooks to manually with a screwdriver, and it won't budge. If you disconnect the cable, the control moves freely.....so its not in the control.

Thanks for the advice everyone. I am going to order a waterpump kit and when I get a free afternoon drop the bottom end and see what I got. I will keep my fingers crossed that this is going to be a simple fix like is described.

On another note, I found another complete bottom end for this motor, in working condition, on ebay for 300 delivered. If this doesn't work and its locked after I drop it, I might just buy that to try to get on the water. Probably cheaper than taking it to the boat shop.

 

[merc850]

Re: 1974 Mercury 85 - Stuck in reverse


This is what the shift cam looks like properly installed. The shift shaft turns CCW to operate the cam. Turn it CW 'til it stops then CCW 'til it stops again, this is FWD, turn it CCW again a few degrees and it will click into neutral. Do not shift into reverse unless engine is running or turning prop at the same time. Install it with the control shifter in neutral.

 

[tlzimmerman]

Re: 1974 Mercury 85 - Stuck in reverse

Finally got around to dropping the rear end....and the lower shift shaft directly into the bottom won't rotate at all. So it looks like its headed to the repair shop to look at the lower end.

 

[tlzimmerman]

Re: 1974 Mercury 85 - Stuck in reverse

Just a follow up in case someone else has the same problem, got the bottom end fixed....it was the shift cam and I think the follower being wore out. 1 hour labor at $70 and 50 in parts....not too bad. Shifts really smooth now.

 

[Maxz695]

Re: 1974 Mercury 85 - Stuck in reverse

never install it in reveres Neural is the best choice for installing the LU if you instal in reverse and the engine is lifted when you sock it up it will destroy the cam this may have been what happend the last time someone did it good luck

 

[merc850]

Re: 1974 Mercury 85 - Stuck in reverse

Just a follow up in case someone else has the same problem, got the bottom end fixed....it was the shift cam and I think the follower being wore out. 1 hour labor at $70 and 50 in parts....not too bad. Shifts really smooth now.

That is a great deal! Was is a dealer?

 

[tlzimmerman]

Re: 1974 Mercury 85 - Stuck in reverse

No....just a mechanic...he is certified in merc, omc, yamaha...just about everything really. I asked around, and everyone who has dealt with him has great reviews....and I agree with them. He even gave me tips on installing the lower end again as well as working on my control. I will gladly drive the distance to him again.

 

[tlzimmerman]

Re: 1974 Mercury 85 - Stuck in reverse

Well its not all said and done quite yet. At home on muffs it would go in and out of both forward and reverse (reverse just barely), at the lake, it won't go into reverse. I can adjust and get reverse, but then I have no forward. Took the control apart, and looks like they were mashing on it trying to get it out of reverse and rounded off part of one of the pieces of the control. Checked, that piece is like $100 from my mechanic...yikes, but I don't want to have to rig up another key somehow or rewire the engine/gauges.

Got lucky, found the same control on ebay that has been gutted, no electrical or cables, for $25 and free shipping. I jumped on it. Hopefully it will be here next week, I can get the new piece in the control, and then I will have forward and reverse without adjusting the barrel on the cable each time I want to change LOL. I have a 4 day weekend next week and want to spend alot of it at the lake!

 

[Maxz695]

Re: 1974 Mercury 85 - Stuck in reverse

correct

 

[tlzimmerman]

Re: 1974 Mercury 85 - Stuck in reverse

correct

Huh?

 

[Maxz695]

Re: 1974 Mercury 85 - Stuck in reverse

was posted tin reply to the first page accidently but glad he fixed the cam and got the shifter part.