1981 johnson 115 hp TNT goes down but not up

whataday

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Oct 12, 2012
Messages
48
Hi Guys, I'm back and still trying to fix this TNT unit. I posted ealier before I went to the parts store, but I don't see my post so I must have hit something wrong. So this is what is happening now. Before taking it off the boat, I decided to check the relay, which actually is a solenoid, not a relay. Found some corroded wires so I cleaned them (actually cleaned all of the wires really good). After cleaning them, I now have motor sound when pressing the down button, but nothing pressing the up button. The marine shop said it was probably a bad solenoid. I am able to bypass the solenoid by using a wire and touching the 2 large connectors on the top of the solenoid, which does give me sound from the motor. So I went ahead and got a new solenoid, got a matching one from the auto parts store since the marine shop can't get one in stock til next week. Then got 2 tubes of fluid and started refilling the hydraulic reservoir. Squeezed in some fluid til it started coming back out, then let the motor down manually til it hit the hydraulic plungers, then lowered it the rest of the way with the down button, then tried to raise it (by bypassing the solenoid since the up button isn't giving me any results), then repeated that about 4-5 times to get the air out. It goes down no problem, but still won't come back up. I raised the motor manually and locked it up, and using my wires to bypass the solenoid, raised it using the TNT motor, and the hydraulic plungers are coming out, and look to be coming out as far as they can, but with the weight of the motor on them, they won't come out to raise the motor. I am noticing when I raise it manually, the hydraulic cylinder in the center between the TNT motor and the cylinder I put the fluid in, comes up a lot, which is what I'm guessing gets the motor up into trailering position, since those two other plungers can only come out so far. Initially when I started this thread, I was wanting to know how to disable the whole system to get my motor down where it should be, but now that I have discovered the TNT motor is not bad, like I was told by the first marine shop, and I have it going down, I don't wanna quit. I want to get it going up now. So, does anyone have any thoughts on why it won't go up now? To repeat myself, it will go down using the down button, and when I use a wire to bypass the solenoid, I get motor sounds where it should be going up, but the hydraulic plungers are not going up (coming out) with the weight of the motor on them. The 2 hydraulic plungers in the center are coming out if I give it some assistance or when I already have the motor raised manually, and they will hold it up when I let go, but they will not bring it up without my assistance with the weight of the motor on them. Any Thoughts???? I read another thread where they were talking about a limit switch? Is that something that would allow me to be getting motor sounds like it's trying to go up, but no actual action at the motor? Thanks,
Johnson 115 tnt solenoid pic.jpg
2012-11-14_14-58-58_659_2.jpg
 

boobie

Supreme Mariner
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Nov 5, 2009
Messages
20,826
Re: 1981 johnson 115 hp TNT goes down but not up

You've got an automotive solenoid there and it also looks like you have it wired wrong.
 

whataday

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Oct 12, 2012
Messages
48
Re: 1981 johnson 115 hp TNT goes down but not up

The picture I posted is what was on the boat before I took it off and that is how it was wired as well. When I went to the parts section on here and keyed it in, it brought up a picture of a solenoid that looks just like my picture.If you have any thoughts on the what the correct solenoid should be and how it should be wired, I'd appreciate any help. Thanks,
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1981 johnson 115 hp TNT goes down but not up

You have found that repeated refilling and activating the trim up/down will self bleed the air out of the system. After doing this, the oil level in the reservoir should eventually maintain a level even with the bottom of the fill hole. Usually, when the two trim pegs get pushed into the out position, then the tilt cylinder will activate. The down on your trim needs very little current, so the motor is wired direct through the trim switch on the handle of the control box. It's the "up" movement that takes all the current, and is the reason why the solenoid is there-to handle the heavy current loads when trimming the engine up-under power. You need to have two good components in the circuit, a good trim switch or control box handle and a good solenoid. If your unit was run without a solenoid in the "up" circuit for any period of time, the "Up" side of the switch may have burned out. Check for continuity through the switch when in the "up" position.
 

gonefishin485

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Jun 29, 2008
Messages
108
Re: 1981 johnson 115 hp TNT goes down but not up

what im going to suggest probably isnt the best or the right way to fix it, but it will get you started on the right path. i say go to the horses mouth if you can, if you can get access to the wires that come directly out of the tilt/trim motor itself, disconnect them, and jump them over with a battery or jumper cables, if its a 2 wire system one will act as a hot, the other a ground to turn the pump one way, reverse the wires for the opposite direction. if its a 3 wire system, one wire will always be a ground and the other two will either be the lift wire or the lower wire. i say start there and see if your motor lifts and lowers under battery power and then work your way to the soleonoid then to the switch on your control box. it may not be the most scientific or technical way to find your problem, but ive been of the school of thought to find what does work and eleminate them from the equation, and eventually your left with your culprit. i hope you get it going!
 

Rmoore45

Seaman
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Aug 4, 2011
Messages
68
Re: 1981 johnson 115 hp TNT goes down but not up

what im going to suggest probably isn't the best or the right way to fix it, but it will get you started on the right path. i say go to the horses mouth if you can, if you can get access to the wires that come directly out of the tilt/trim motor itself, disconnect them, and jump them over with a battery or jumper cables, if its a 2 wire system one will act as a hot, the other a ground to turn the pump one way, reverse the wires for the opposite direction. if its a 3 wire system, one wire will always be a ground and the other two will either be the lift wire or the lower wire. i say start there and see if your motor lifts and lowers under battery power and then work your way to the solenoid then to the switch on your control box. it may not be the most scientific or technical way to find your problem, but Ive been of the school of thought to find what does work and eliminate them from the equation, and eventually your left with your culprit. i hope you get it going!

This is what I was going to suggest but you beat me to it. I have a '78 115 and I currently have it on a stand, when I want to raise/lower the motor I just touch the wires coming from the motor to the battery. Mine is a 3 wire motor, I believe yours should be to judging by the solenoid setup. On my motor black is ground, blue is up, and green is down. Hopefully this will help. It's weird that the motor goes up but not down, probably just a loose/bad connection on the wire or the switch might be bad.

If, no, When you get it working properly I bet that you're not going to want to get rid of the TNT after all. If you decide to keep it I would recommend changing out the solenoid and direct wire system to a modern relay system like I have done here . It works better and makes it easier to diagnose problems if any ever arise.
 

whataday

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Oct 12, 2012
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Re: 1981 johnson 115 hp TNT goes down but not up

This is what I was going to suggest but you beat me to it. I have a '78 115 and I currently have it on a stand, when I want to raise/lower the motor I just touch the wires coming from the motor to the battery. Mine is a 3 wire motor, I believe yours should be to judging by the solenoid setup. On my motor black is ground, blue is up, and green is down. Hopefully this will help. It's weird that the motor goes up but not down, probably just a loose/bad connection on the wire or the switch might be bad.

If, no, When you get it working properly I bet that you're not going to want to get rid of the TNT after all. If you decide to keep it I would recommend changing out the solenoid and direct wire system to a modern relay system like I have done here . It works better and makes it easier to diagnose problems if any ever arise.
2012-11-14_14-58-58_659_2.jpg

Actually, it goes DOWN, but not up with the weight of the motor on it. Today after working on it a bit more, we finally got it to go up some, still having to bypass the solenoid and jumping it with a wire, but it still won't go up in to trailering position. I had someone over at the house doing some work today, and he looked at it and told me there is an impeller (that's what he called it), underneath the TNT motor, said it works like a pump to get the hydraulic fluid in to the cylinders. Said I should replace that and try again to see if it will go on up in to trailering position. But I cannot locate a part on the diagram I found called an impeller (I do know what a water pump impeller is ). Closest thing I could find that looks to be under the motor is called an oil pump assembly, and heck, that one little piece is almost $300. So, I guess tomorrow, I'll start back on it like you said and start at the motor and work back towards the solenoid then the controls and see where I get. Thanks for the suggestions. I'll be back when I get that done.
 

whataday

Seaman Apprentice
Joined
Oct 12, 2012
Messages
48
Re: 1981 johnson 115 hp TNT goes down but not up

You have found that repeated refilling and activating the trim up/down will self bleed the air out of the system. After doing this, the oil level in the reservoir should eventually maintain a level even with the bottom of the fill hole. Usually, when the two trim pegs get pushed into the out position, then the tilt cylinder will activate. The down on your trim needs very little current, so the motor is wired direct through the trim switch on the handle of the control box. It's the "up" movement that takes all the current, and is the reason why the solenoid is there-to handle the heavy current loads when trimming the engine up-under power. You need to have two good components in the circuit, a good trim switch or control box handle and a good solenoid. If your unit was run without a solenoid in the "up" circuit for any period of time, the "Up" side of the switch may have burned out. Check for continuity through the switch when in the "up" position.

I checked the trim switch, and it's good. I put a new solenoid on it last nite, and if I jump it using the 2 large posts, it get action (going up of course), but I was told to truly test the solenoid, I should jump it from the positive large post to the smaller posts with the blue wire and if the solenoid is good, it should activate the motor, but I am not getting anything at all jumping it that way, so I've got to figure that one out now.
View attachment 175369
This picture is of the old solenoid and how it was wired before I started messing with it.
Like I mentioned before, the solenoid I put on it, I bought from the parts store, cause the marine shop couldn't get on here til Monday and I wanted to try to get something accomplished before Monday. I'm getting the same results from this new solenoid as I did the old one. I know both solenoids are 12V, but could there be any other difference being automotive that could be keeping it from working properly, like amps????? Thanks guys, appreciate your help.
 

Rmoore45

Seaman
Joined
Aug 4, 2011
Messages
68
Re: 1981 johnson 115 hp TNT goes down but not up

There is no difference between automotive and marine solenoids besides the word "marine" and the price.A solenoid is a solenoid.

Either I'm having a hard time understanding your previous posts (I'm tired and it 12:30), you're saying that you can jump the two big terminals on the solenoid and the the electric motor is energized but it just won't push the motor up because there is too much load. If that's the case then there is a problem. First check all the little things, everything on/around the motor. I have to ask, is the manual release screw all the way screwed in and closed? I know it's just a little thing but if there is not a good seal there then the motor will not go up.

Tomorrow I will try to take a video of my motor and its TNT setup which is exactly like yours. I inclined to think that this is one of those things that you just need another set of eyes (who knows the TNT system very well) to look at the problem and could fix it in 5 minutes.
 

whataday

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Joined
Oct 12, 2012
Messages
48
Re: 1981 johnson 115 hp TNT goes down but not up

There is no difference between automotive and marine solenoids besides the word "marine" and the price.A solenoid is a solenoid.

Either I'm having a hard time understanding your previous posts (I'm tired and it 12:30), you're saying that you can jump the two big terminals on the solenoid and the the electric motor is energized but it just won't push the motor up because there is too much load. If that's the case then there is a problem. First check all the little things, everything on/around the motor. I have to ask, is the manual release screw all the way screwed in and closed? I know it's just a little thing but if there is not a good seal there then the motor will not go up.

Tomorrow I will try to take a video of my motor and its TNT setup which is exactly like yours. I inclined to think that this is one of those things that you just need another set of eyes (who knows the TNT system very well) to look at the problem and could fix it in 5 minutes.

The manual release screw is all the way tightened. The problem point I am at now is still I'm getting nothing when I push UP on the trim switch. I did check for continuity and it is showing good on the meter. If I go to the solenoid, and touch the two large terminals with my wire, it is now going up, but only about 1/2 as far as the trim pegs will go out, it won't go all the way or into trailering position. Is there a limit switch (i read somewhere something about that), that could be stopping it from going any higher? I'm going to head back out there shortly and take the wires loose and try to jump it straight from the battery I guess and I'll post what I get with that. Mine is a 3 wire setup. Thanks for all your help. I really do appreciate your offer to video yours for me.

Alright, just went out and tested it straight from the TNT motor wires directly to the battery. Down is still working fine, but up is still only going up slightly, about 1/2 the length of the hydraulic pistons(trim pegs). I did notice this, and maybe it is supposed to do this, but when I manually lift the motor all the way up, then lower it back down slowly, I noticed the trim pegs come the rest of the way out as I am lowering it, then when the motor reaches the pegs, they push back in to where they were (about 1/2 way out). I checked my fluid level again and as soon as I loosened the screw fluid started running out, so I know, or think anyway, it has plenty of fluid in there. I am thinking it not going up has something to do with the trim cylinder, but have no clue what, if at all?
 

whataday

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Re: 1981 johnson 115 hp TNT goes down but not up

Just thought I'd let everyone know, I got it fixed. I had given up, and was taking it off to replace the whole unit. Once I got it un-bolted and the rod out of the trim cylinder, I decided to try it one last time with no resistance from the motor on it. I raised and lowered it a few times, and it seemed to do fine without any resistance, which left my totally baffled, so I decided to put the bolts and rod back in and try it ONE LAST TIME before completely taking if off. It worked. Goes down just fine, goes up, and ALL the way up, just fine, and even fast once the trim cylinder kicks in. Guess it was just in a bind somewhere and needed to get worked loose. Hope that's all it was anyway. I've raised and lowered it about a half a dozen times, just to make sure, and it's still going. Thanks to all of you who offered help and suggestions. I may be new to all of this, but I'm learning.
 
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