1977 Johnson - No Reverse - Rebuilding lower unit now have 2 specific questions

spencroy

Petty Officer 3rd Class
Joined
Sep 26, 2007
Messages
86
Hello Guys,
I have 2 specific questions at the bottom of this post.

Brief History: I have not had reverse in this boat since purchasing it about 1 year ago. The suspected reason was the previous owners "creative solution" to replacing the shift cable (AKA "redneck it"):
image2.jpg


Symptom: The unit would shift into forward and neutral without issue, but when I would pull the lever back, it would make a clicking sound and would only reverse very slowly.

I asked about it on this fourm and was told the possibilities include:
- bad cable (length etc)
- possible bad clutch dog

Due to another issue I had to go into the lower unit anyway this weekend:
http://forums.iboats.com/showthread.php?t=272197

And decided to check on the clutch-dog while I was there.

After droping the lower unit I noticed that:
- pulling the shift rod up engaged foward (prop would only turn one direction)
- pushing down hit netural no problem (prop shaft turned both ways)
- but was not able to push down into reverse easily
(However, truth be told at this point in the process I did not have a full grasp of how the parts worked, so I did not push down on the shift rod to forcefully)

Removed the shift rod/housing
removed from the prop to reverse gear
removed the prop shaft and shift/rod/assist solenoid

Examined the clutch-dog
- There is not signs of water or corrosion
- The clutch dog will slide forward, neutral, reverse, but it is very stiff
- All gears on internal side of clutch dog are fine
- Forward side of clutch dog is fine
- Some earmarking on reverse side of clutch dog.

Examined reverse gear. Same story, earmarking but more than 1/2 the tooth is still left

put reverse gear on prop shaft, when clutch dog is FULLY engaged in reverse the teeth match up ok, dont slip. Suspect the ear marking was caused by the bad cable length preventing the clutch dog from fully engaging.

Decided to grease up the clutch dog
(WAS this a bad move? Should I clean it up and just let the oil do its thing?)

After applying grease found the clutch dog much easier to move forward and reverse.

Decided at this point to reassemble and test (and this is where I hit the wall)
I was able to remove those retaining rings with a long pair of needle nose pliers
image3.jpg

As you might guess there is no way on earth they are going back in with this tool.

I am currently waiting on a friend of a friend who has a pair of snap ring pliers he will let me borrow tonight. When I have the ring(s) back (and I understand the danger of these rings) in place my logic is that if I can engage the shift rod up/middle/down and the prop shaft moves as expected then I can survive without replacing clutchdog/reverse gear (assuming the prop turns only the direction expected)
(I dont want to pay 500 bucks for those two parts considering I only spent 1000 on the boat)

However, my specific questions are:
1. Was greasing the clutch dog a stupid move?
2. On the shift rod there is what the book calls and "Assist Solenioid". I cant seem to get my brain around what exactly this does. Can anyone explain that part to me?

Thanks
Roy
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: 1977 Johnson - No Reverse - Rebuilding lower unit now have 2 specific questions

Grease won't hurt anything, but won't stay put either.

There's no solenoid or anything electric associated with your gearcase. I would lose the funky control thing and get a proper single lever control unit (Ebay, Craig's List etc.) You may have a manual for a much older motor ... not very helpful. The reverse side of the clutch dog and Rev gear may be pretty beaten up from lack of proper engagement. Are you calling the oil pump a solenoid?

Gearcase parts:

http://12.2.215.22/pub/default.asp?...=EJ,ATV,SEADOO,SKIDOO,SPORTBOAT,LYNX,ROADSTER
 

spencroy

Petty Officer 3rd Class
Joined
Sep 26, 2007
Messages
86
Re: 1977 Johnson - No Reverse - Rebuilding lower unit now have 2 specific questions

Hello Jim,
Thanks for the reply, I am just heading to the house to begin my troubleshooting (finally got a pair of snap ring pliers that will do the job)

I think it is probable that I am calling the oil pump and assist solenoid. I will take a picture of it tonight so it makes it clear
(but its the parts 50 - 58 in the BRP catalog for the 1977 Johnson 115EL77S - specifically the parts 50 - 54 it seems)

Assuming this is the oil pump what is its function (I am trying to determine if this part is in good working order)

My manual is a bit of a problem. I got the SELOC version that covers every year in history but the 77 it seems :-( I love the parts in the book where it goes "from 1968 to 1975 use section1, for 1979 - present use section 2".. grrrr where is section 3 covering my year??

Thanks for the tip on the grease. Just wanting to make sure I do as little harm as possible. I agree I need to repair the command center (in reality it will take about 200 in parts) but the thing is I have sorta gotten used to having the separate controls. I can rev the engine without having it in gear when its acting funny.. I know. .no excuse.

Thanks for the post (I can debug tonight with a little more confidence)
Roy
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: 1977 Johnson - No Reverse - Rebuilding lower unit now have 2 specific questions

Actually, what you have is power assisted shifting. It works on the same general principle as power steering on a car. You turn the steering wheel, which moves a control valve, directing oil under pressure to a cylinder that turns the wheels. Except here the cylinder moves the clutch dog. A car has backup manual steering in case of power failure. Your outboard has manual backup of the shifting for the same reason.

All that to say, yes there is an assist servo assembly in the same cavity where the solenoids used to be on the old Hydro-Electric units.

The oil pump provides the hydraulic pressure to the servo valve and shift cylinder. I believe it also pumps oil up to the upper drive shaft bearing, if I remember correctly.
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: 1977 Johnson - No Reverse - Rebuilding lower unit now have 2 specific questions

"I agree I need to repair the command center (in reality it will take about 200 in parts) but the thing is I have sorta gotten used to having the separate controls."

Forget the 200 parts and just replace with a decent used one. You SHOULDN'T be revving the motor in neutral anyway (unless you don't mind a rod going thru the block or something else ugly). A manual specifically for your motor might be helpful also.
 

spencroy

Petty Officer 3rd Class
Joined
Sep 26, 2007
Messages
86
Re: 1977 Johnson - No Reverse - Rebuilding lower unit now have 2 specific questions

Hello Guys,
Thanks for all the advice and help. I wanted to give a quick update.

1. F_R, to your point of reving the engine in neutral, point well taken. I am never reving very high, but for some reason (I will create a post when I am ready to start debugging that issue) when I start off sometimes the motor dies. If I give her a little rev, then slip into gear, I have no trouble getting out of the hole and taking off

2. To wilde1j's point, I will be looking around to find a good replacement command center.

3. Finally, I wanted to thank F_R for describing the servo. I have attached a picture of the unit to make sure we are all talking about the same thing:
image4.jpg


I am hopeful I am at least mechanically enclined enough to have it right (down is forward, up is reverse? as I had the opposite understanding before I took it apart) I am still concerned about this part. To me it seems that the servo (oil pump, or what not) may not be working correctly. However, its function even with F_Rs description still escapes me a little.

With the lower unit reassembled (or at least with the snap rings (from hell)back in place) I am noticing that if the shift rod is FULLY in position then the prop moves as expected when the drive shaft is turned (although it is very difficult to shift, I have to apply a bit of pressure to get it forward and reverse, but the unit is empty, I am hopeful with oil it will be better) They key for me in final assembly will be to make certain I am getting the clutch dog fully engaged. I will be working on that after I get all my parts in.

Thanks so much for your help on this one guys!
Roy
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: 1977 Johnson - No Reverse - Rebuilding lower unit now have 2 specific questions

The hydraulic assist may well be hard to shift with a) the engine not running and/or b) the driveshaft (or prop) not being rotated while shifting. The dog can only engage the gears in specific areas of the gears. As long as the dog moved freely on the prop shaft, I wouldn't be too worried. I'd be more worried about how beat up the gear and dog are.
 
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