1975 Johnson 135 questions

[younggun]

I just recently got a boat with a 135 Johnson on it and have a few questions.
1. The tilt and trim on the motor are not working and I touched the wires straight to the battery and nothing happened. What should I try next or what do you think is wrong with it?
2. There is a tach in the boat but is not hooked to the motor. How would I need to hook this up?
Thanks in advance!

 

[emdsapmgr]

Re: 1975 Johnson 135 questions

It's actually a fairly simple system-I'd check the motor out first, then the solenoid and switch. The original factory manual has a page and a half about troubleshooting the electrical system on this unit-with a simple household voltmeter. (Unlike later models, there is no fuse put in the system from the factory.) You can get an original factory service manual from this website: outboardbooks.com The factory left an stubbed off gray wire inside the control box. That wire is the signal wire to drive the tach. You will need to pull the box apart to locate that wire. The wire fits inside a hole at the bottom of the two halves of the control box. It will drive any marine type tach.

 

[younggun]

Re: 1975 Johnson 135 questions

The only problem with the tach is the control box is not the factory one. Would if be easier to just get a tiny tach and install it instead since the control box is different? And then I would have an hour meter too. Thanks for your reply

 

[F_R]

Re: 1975 Johnson 135 questions

Please elaborate on how you touched the wires to the battery. Do you mean both wires,, to positive & negative? That won't work. You need to ground the motor to battery negative, and touch wires one at a time to positive. One goes up, other down.

The wires are all in the control for a tach. Or, in your case the cable leading to the control-----if you have it. Otherwise, a tach needs three wires, purple from ignition switch, black to ground, and grey from alternator. It is simple and there are lots of available tachs out there, including here at iboats. You need an alternator tach, almost all are, nowadays.

 

[younggun]

Re: 1975 Johnson 135 questions

I touched the black wire to the negative and then touched the other ones to the positive one at a time and nothing happened. I did touch the other two positive and negative and they started arching so I figured that was t the way to do it

 

[emdsapmgr]

Re: 1975 Johnson 135 questions

If, for some reason, you have a factory harness going to the control box, it should already have a gray wire inside the harness at the control box end. If not, you can run your own tach signal wire from the engine, up to the gauge on the dash. The tach wire would originate on the engine: Connect it up to screw #7 on the terminal strip on the side of the engine. There should already be a wire there: yellow with a grey tracer.

 

[younggun]

Re: 1975 Johnson 135 questions

Would I need to use any special kind of wire? Also I read somewhere that these motors need to be run on premium gas. Is this true?

 

[younggun]

Re: 1975 Johnson 135 questions

The motor has compression of 155-165 on all 4. Am I correct that this is a high compression motor?

 

[racerone]

Re: 1975 Johnson 135 questions

Well for one thing there were factory head gaskets to lower compression ( thicker ) so running premium fuel is the right thing to do.

 

[younggun]

Re: 1975 Johnson 135 questions

Thanks. Does anyone know if I need a special wire to run to the tach if the normal one is not present?

 

[emdsapmgr]

Re: 1975 Johnson 135 questions

The wire is nothing special, but I'd use a marine type 14 gauge stranded/tinned wire. You can buy it in bulk, or on a spool/roll at most marine dealerships. Those early 135's ran very high compression, compared to later crossflows. Still your numbers seem somewhat high. I'd be surprised if they were actually over 140. In any event, the compression is in "like new" condition! I run 92 octane in all my older high compression crossflows. Later (mid 80's) crossflows ran 95-100 lbs compression on 87 octane ethanol fuel.

 

[younggun]

Re: 1975 Johnson 135 questions

Thanks. The guy I got it from said he purchased it from the original owner about 5 years ago and he said he had hardly used it since new and then the guy I got it from used it less than 10 times. So it seems like it has not been used much at all

 

[younggun]

Re: 1975 Johnson 135 questions

The wires are cut off about 3 feet from the tilt/trim motor. I tried touching them straight to the battery and nothing. What should I do next?

 

[crb478]

Re: 1975 Johnson 135 questions

The wires are cut off about 3 feet from the tilt/trim motor. I tried touching them straight to the battery and nothing. What should I do next?

Disconnect the motor form the rest of the T/T and see if it is locked up or if it will turn. If it turns try to connect it directly to the battery and see if it now runs in both directions. If it doesn't you need a new motor or to rebuild that one. If it does look for other problems in the T/T. There were two different motors used from the factory so make sure which one you have before ordering a new one.

 

[younggun]

Re: 1975 Johnson 135 questions

The motor did nothing. Can I just use the trim holes with a trim rod until I get a new t/t motor? Would I be better off to just get a cmc plate for the motor instead of trying to replace the motor? because it looks like the seals around the rods are cracked up pretty bad so I will probably have to do more than just motor. Also where would the serial number be located besides the plate because the serial number plate is painted over?

 

[emdsapmgr]

Re: 1975 Johnson 135 questions

There is another/identical serial number stamped on a casting plug on the top of the engine. Likely it's painted over, but has the serial and model number stamped there. It's the model number you are looking for. See pic:

 

[younggun]

Re: 1975 Johnson 135 questions

I can't seem to find that on top of the engine. Anywhere in particular I should look?

 

[Bosunsmate]

Re: 1975 Johnson 135 questions

I can't seem to find that on top of the engine. Anywhere in particular I should look?

look up what a welch plug looks like and then look all over the rear half of the block for it

 

[emdsapmgr]

Re: 1975 Johnson 135 questions

It's on the top of the port cylinder of the block. About the size of a quarter.

 

[younggun]

Re: 1975 Johnson 135 questions

I don't know if I will get to check today or not but will the first chance I get. It has been raining all day yesterday and today