1971 Johnson, HYDROELECTRIC shift. jumping out of gear

[jwilkey84]

I am helping a buddy work on an old hydroelectric shift motor, which we dont know a whole lot about, other than everyone says to stay away from them. It is a 60hp 1971 johnson, and we just got it running, but he took it to the water and says it goes a little ways then revs up and the motor shakes and then it will go back to regular rpms and continue to go. This happens over and over, and I dont mean at high speed either. He was afaraid to open it up because of this problem..... He thinks that the motos is coming out of gear because of something wrong in the hydroelectric shift mechanism, and yes it does have the correct oil in it. BUT it also needs to have the lower unit seals re done, so the LU oil is contaminated with water. I tend to think that the ears on the clutch dog are worn, and making it jump out of gear. We had heard that these motors are very sensitive to water interfering with the LU oil causing it not to shift correctly, but I think the clutch dog might need some repari, what do you guys think?

 

[tx1961whaler]

Re: 1971 Johnson, HYDROELECTRIC shift. jumping out of gear

First make sure the battery is fully charged and that the shift switch and wiring are good.
I think that the lower unit should be flushed out with ATF, run it on the hose and work the gears and change the fluid a couple of times to get the junk out of the pump and passages. Then refill with the Type C oil and see how it does on the water. A couple of quarts of ATF is a lot cheaper than a clutch dog, and it needs flushed out and re-sealed anyway.

 

[eavega]

Re: 1971 Johnson, HYDROELECTRIC shift. jumping out of gear

Check to see if you have a spun prop. Scribe a mark on the prop shaft and hub. Run the boat in the water, and when it revs up, check to see if the marks still line up. If they don't, you have a spun prop.
Of course, fix the leaking LU as soon as possible, since that can cause damage if left unattended.

Rgds

Eric

 

[jwilkey84]

Re: 1971 Johnson, HYDROELECTRIC shift. jumping out of gear

Check to see if you have a spun prop. Scribe a mark on the prop shaft and hub. Run the boat in the water, and when it revs up, check to see if the marks still line up. If they don't, you have a spun prop.
Of course, fix the leaking LU as soon as possible, since that can cause damage if left unattended.

Rgds

Eric

So this is gonna sound dumb, but what is actually happening when one does have a spun prop? My gut feeling is the clutch dog. I actually took one apart one time and just used a die grinder to square up the edges of a clutch dog one time and it seemed to work ok. And this is a low budget project on an old boat that wont get used much so I figure thats what we'll do again if thats the problem.

 

[rockyrude]

Re: 1971 Johnson, HYDROELECTRIC shift. jumping out of gear

There is a rubber sleeve between the propshaft and the prop. With age they can break letting the propshaft spin inside of the prop. Putting a mark across everything will immediately show if the hub is spinning inside of the prop. This repair is faster than a tear-down for a suspected problem.