johnson shift rod

[jwilkey84]

does anyone know the different length of shift rods for johnson 1980's 40-70 hp motors. I assume there different lengths to accomodate different lengths of shafts. You know, the difference between a 15" short shaft motor and a 20" shaft motor is 5". But is there different lengths besides that. The reason I am asking is that I did a lower unit swap, and I have my linkage all hooked up and have adjusted my cables as far as they will go, but the motor will not quite go into reverse. And you barely have to touch the shifter to shift into forward gear. I just cant figure it out. Could I possibly need new cables? Could there be something wrong in my control box? Or, did they make shift rods in increments of something crazy like 1/4" increments? The crazy thing is that all of this stuff worked two weeks ago before the original lower unit crappped out. Also since then, I have had an overheat problem. I don't get it, the lower unit crapped out and now it also wont shift and get hot. the tstat is 6 months old, impeller is new, and water comes out of pee hole.?????????????????????????????????????????????????????????????????????????????????????????????????????? Please any theories would be apperciated before I pull my hair out!!!

 

[Joe Reeves]

Re: johnson shift rod

Starting at the beginning........

Did the lower unit that you're now using have the same shift rod as the original lower unit, OR......

Did you switch the shift rod from the original lower unit to the lower unit that you're now using?

Exactly what engine are you speaking of?

 

[kjdunne]

Re: johnson shift rod

Shift rod length is critical. What year & model? Short or long shaft?

 

[jwilkey84]

Re: johnson shift rod

The motor is a 1983 johnson 50 hp, (J50BELCTA) long (20") shaft. The lower unit I installed is supposedly from a 1986 40 hp long shaft johnson. The only difference visually between the two is that my 1983 LU had an anode, and this replacement (1986?) does not have one. Other than that they look identical. When I put the replacement lower unit on, I did NOT use the original shift rod because the replacement LU already had one on it. I simply took off my LU from the 1983 model, and replaced it with what I was told was a LU from a 1986 johnson 40 hp long shaft motor. Then when I took it to the lake, it would not shift properly, and the motor got hot enough to make my alarm go off (which had previously never happened). So I took the replacement LU off and inspected the impeller and housing, everything looked good, but I put a new impeller in while I was in there. Since then I have not had the motor started, but I have checked compression and I still have 120 in both cylinders. Could there be anything about a lower unit that would make a motor overheat, aside from the water pump failing? Could the LU have the wrong gears in it or something? The gentleman I bought this LU from said he bought it from a marina in Florida off ebay, because his went bad. Well he said he had it on his boat for 5 hours, and then he had a rod break so his motor was shot. So he sold me this LU with 5 hours on it. Could there be something inside the gearcase that is ruining motors? It sounds far fetched, but I have no idea at this point.

 

[Joe Reeves]

Re: johnson shift rod

Measurement is from the top surface of the lower unit to the center of the shift rod hole.

1983 - 1985 - 40, 50, 60hp = (S) 15-29/32" - - (L) 20-29/32" plus/minus 1/32" Have the shift rod in neutral and offset to the rear.

Overheating? Key could have slipped out of the impeller. Impeller may be weak. Pump housing could be scored. Water tube could have missed the impeller housing guide. Impeller housing may have hit the tube and pushed it upwards. Thermostat may be sticking.

 

[jwilkey84]

Re: johnson shift rod

I have the shift rod offset to the rear, I checked the impeller and housing after overheating-all good. Tstat was replaced 7 months ago. BTW, the whold time I was overheating there was water coming out of the tell tale. Suppose it could be the tstat again, already???? I hate that job!! Also, if my shift rod was not the right length, I wouldn't even be able to connect it to the linkage up above would I?

 

[Joe Reeves]

Re: johnson shift rod

Yes, you would be able to connect the shift rod even if it was set to the wrong length...... that's why the measurement is critical.

 

[jwilkey84]

Re: johnson shift rod

I have the lower unit completely installed, all the bolts connected, and the shift rod secured in its place....and you are telling me that I could have the wrong length shift rod in place? If there is 5" difference in shift rod lengths...........I am not understanding how it would be possible for everything to go back together just fine, if the rod was the wrong length. I mean if it was lacking 5" it would not reach its receiver.....if it was 5" too long then when attched to the receiver, the rest of the lower unit would hang offf the bottom of the motor 5". Maybe I am a complete idiot, but I am not understanding how i could be using a shift rod that is the wrong length. I could understand if there was only like 1/2" difference between the two possible lengths of rods, but 5"! you would not even be able to put the thing together!

 

[Joe Reeves]

Re: johnson shift rod

The shift rod screws into the lower unit. If it is screwed in too far or too little, the measurement is wrong.

You've been given expert advice from people in the know who have serviced these engines for many years in a professional capacity. You do not need to understand fully of what we speak...... simply follow our advice to the letter and correct the problem.

If on the other hand you would prefer to continually question what we have to say and prefer to go your own route, guessing and tinkering with various adjustments that could lead to extensive damage, be our guest. We volunteer our time and knowledge freely but we do get a little irked when we reach a point where we feel that we are wasting our time.

 

[jwilkey84]

Re: johnson shift rod

Let me apologize, I did not fully understand what you were trying to tell me. I thought you were trying to tell me that I was using the WRONG shift rod all together...I did not know that you were trying to tell me that it could just be an issue dealing with how far the rod was threaded into the LU. I appreciate all the help I find on here, dont get me wrong. But also, sometimes I feel like some of the respondents skim over a thread, not taking it all in, and then real quick type a reply that a lot of times contains info that makes me feel like you dont fully understand the nature of the original question/problem. For instance, this whole time I thought you people were trying to tell me that the actual physical length of my shift rod was the problem. When, in fact all you would have had to say was: Hey, screw your shift rod in or out until you have 20-29/32" +- 1/32" from the top surface of the LU to the center of the shift rod hole. This forum is filled with people who know less than you, and a lot of times this is our first time at a specific task. Just like a baby, sometimes we need to be spoonfed with out having the spoon shoved down our throat.

 

[jwilkey84]

Re: johnson shift rod

Well, I got the shift rod ADJUSTED to the correct length. Now its off to the lake to see how it really works. I anticipate much better than before. Now if I can just be lucky enough to not overheat!!

 

[Joe Reeves]

Re: johnson shift rod

How far off was the adjustment?

 

[jwilkey84]

Re: johnson shift rod

I was really surprised how far off it was! I dont know for sure, but when I looked at my tape measure I knew immediately that was my problem. If I remember right it was like at least 3/8" off. I think I turned it our at least 6 complete turns. I didnt understand until last night that that rod even twisted in and out. I knew it would spin, but I didn't know that was how you adjusted it. Sorry I questioned your advice, but I wasn't comprehending. Had it on the water today shifted better than ever and didn't overheat. Hope to be tubing again tomorrow! Thanks.