Hey. im new to the forum, and almost new to fishing as well. we have a bass boat with a 77 johnson motor, 85 hp… the motor is running good, but the transmission is ruined... we took it appart and the gears are no good any more… so im looking to replace it. the long shaft that goes to the motor has 20 grooves, if that makes any difference…so, do you know where can I get one??

thanx!!

anyone?? maybe a junkyard or something??

thanx!!

Well, your transmission is called the Lower Unit.

I think you might have a hard time finding one for that motor. It was about 77 or 78 they used a different unit that had a shif assist unit that didn't work out but if yours is one of those, you have a major problem. They shifted backwards than all others so if you installed any other model, push you handle forward and it puts the motor in reverse and pulling it back puts the motor in forward. The parts to correct this problem will be very expensive. I have built parts and modified one motor. Most people stuck with that setup just install a hot foot and only use the handle to shift. Just don't let a stranger drive the boat.

thanx for the reply. i dont think i have the lower unit you mention, since when i push the handle forward, it goes forward, just very slow.... when i accelerate the motor, it would go in neutral....

after we took it appart, we noticed that the forward gear had rounded edges where it contacts the clutch dog. also, i noticed the clutch dog was not movoing freely, it was stuck and very hard to move. so we took it apart, and since it also showed some wear, we put it backwards. then, we sanded the rounded edges, until the contact points were straight again.

so now the part of the clutch dog that previously contacted the reverse gear, will now engage with the forward gear, and we sanded the forward gear to eliminate the round edges and now has square edges. do you think that will work until we get a lower unit?? unfortunately we live in Mexico, where getting replacement parts is expensive and difficult...

thanx!!

You miss understood. On the motor the lower unit goes on, the shifter works normal, forward on the handle is forward, back on the handle is reverse. The problem comes in when you try to install a different year model lower unit. The particular lower unit I'm talking about only works on that year model. If you put it on any other year model motor, or if you put any other year models Lower unit on that motor is where the problem comes in. In either case, they will shift backwards. I'm fairly certain it was the 1977 models they did that with, but not sure enough that I would bet the ranch on it.

As for putting it together backwards, it might work for a while but take it easy in forward. I think you noticed the forward has more notches, or bigger notches and is much much stronger than the reverse gears. That's why when the motor is in reverse, you will feel a lot of play when you hand turn the prop back and fourth, but in forward, there is almost no play. Now yours will be opposite that. Merc guys, your's have a ratchet assy so all it's going to do is turn and click when you turn it backwards.

Youmight be better off looking for a used motor?

You miss understood. On the motor the lower unit goes on, the shifter works normal, forward on the handle is forward, back on the handle is reverse. The problem comes in when you try to install a different year model lower unit. The particular lower unit I'm talking about only works on that year model. If you put it on any other year model motor, or if you put any other year models Lower unit on that motor is where the problem comes in. In either case, they will shift backwards. I'm fairly certain it was the 1977 models they did that with, but not sure enough that I would bet the ranch on it.

As for putting it together backwards, it might work for a while but take it easy in forward. I think you noticed the forward has more notches, or bigger notches and is much much stronger than the reverse gears. That's why when the motor is in reverse, you will feel a lot of play when you hand turn the prop back and fourth, but in forward, there is almost no play. Now yours will be opposite that. Merc guys, your's have a ratchet assy so all it's going to do is turn and click when you turn it backwards.

what do you mean by more notches?? the clutch dog seems to be tsymetrical... and we are not changing the gears... front gear will still be front gear, only the clutch dog, the part that previously contacted the rear gear, will now contact the front, as we turned it 180 degrees in the shaft....

and NBR, we could do that, but i think it would be expensive.... if thats the only way to go, we will have to do it, but we are looking for other options first.... how much does a mid 80s, 85 or so HP costs??

well, i just got me a complete lower unit for $270. It comes from the same motor, so i will just have to install it and put oil in it and i will be ready to run. is it a good price?? it was the only one i could find, so it didnt seem too expensive...

thanx!

well, i just got me a complete lower unit for $270. It comes from the same motor, so i will just have to install it and put oil in it and i will be ready to run. is it a good price?? it was the only one i could find, so it didnt seem too expensive...

thanx!

You pay your money, you take your chances, You get what you pay for...It all means the same, The real question is...Is it worth it to you?

If there is no oil in it, Is that due to the shipping regulations or did it not have any oil when it was advertised?

Look really close at the lower unit case for cracks or damage, Even if it is damaged and you have to use your existing case and IF the gears are in good shape I would say you did good on price considering where you are located.

Good luck!!!