1985 Johnson 150 GT questions/problem

[LiquidCache]

Hey guys, I am new here, I just bought my first boat. It's a 1985 Procraft 1650V with a Johnson 150 GT on it. I have a few questions, and one slight problem.

When I bought the boat, I made sure the engine fired up, and that the trim/tilt worked. I put the engine up, and got her home, to find out that the tilt would no longer allow the engine to go down. I've checked all my connections at the tilt motor and everything is good. I know its not the switch cause there's one on the throttle and one on the back of the boat. The odd part is that the motor will engage UP, but not Down. It's fully up right now.

another question, since i'm new to outboards i have to ask. How can you tell if these engines are overheating? I'm an auto tech for Ford, and that's one of my pet peeves with this boat. It has no temp gauge, so i can't check her vitals.

Thanks!
-Jason

 

[jonesg]

Re: 1985 Johnson 150 GT questions/problem

Mine is a 94 150 , look to see if theres 2 relay's for T/T ,
try swapping them,
this assuming the tilt motor is not getting any juice.

you can still get the factory manuals at
www.kencook.com

With the wiring color code in the manual, check at the controler, wiring colors in my manual are
green/white
red/white
blue/white.

if the tilt motor runs but the leg doesn't move, check the fluid level then unscrew the manual release valve(with leg supported) and lower it by hand. Then raise it and check the fluid level again a couple times, mine had air in the system but the system is easy to bleed , same as power stering on cars, one extreme to the other then top the fluid up.
manual relase is on port side of bracket, its usually marked but hard to read , theres a hole thru the bracket and the valve is in there, need a big screwdriver.

Its usually something simple, but impossible to reach.

 

[emdsapmgr]

Re: 1985 Johnson 150 GT questions/problem

There is a temp switch wired into each head. When the temp of one head gets to 212, it sets off the horn in the control box. When the head temp gets back down to 175 the horn silences. You test the horn by disconnecting the knife connection to the head senders and put them to ground. The horn should sound. The thermostats open at 143, so normal head temps at idle will be from 143 to around 150-155. The heads have pressure relief valves which will open at planing speeds and will flood the engine with extra cooling water. Temps will likely go down somewhat when on plane. As a mechanic, you may have one of the laser temp guns. These are handy and can reassure your concerns.

 

[LiquidCache]

Re: 1985 Johnson 150 GT questions/problem

I do have a temp gun and was going to give that a shot, now that I know what normal operating temp is it will be much easier.

As for the trim, it worked fine going up and down before, now she's full up and the motor won't even engage down. My gauge lights dim when i hit the switch down, and in the automotive world, when you have say, a power window that won't go up or down but the dome lights dim when you hit the switch, that's usually a good sign that the circuit is working, but the motor is bad.

Where are these relays usually located? I haven't seen any *yet*.

How do you lower the engine by hand? I've seen only one screw on the right side of the hydraulics, when i loosened it I heard a slight hiss of air, but that was it. The engine didn't come down or anything like I figured it would.

 

[Dhadley]

Re: 1985 Johnson 150 GT questions/problem

The 1985 came with a 2 wire system so there should be a box on the exhaust cover on the block between the heads. Pop that cover off and swap the relays. If it now goes down but not up, one of the relays is bad.

If it still doesn't come down, disconnect the 2 wires coming from the trim motor. Using 2 jumper wires put one lead to positive and one to ground. If you put the green lead to positive and the blur to ground the motor should come down. Up is blue on positive.

 

[Dhadley]

Re: 1985 Johnson 150 GT questions/problem

We're assuming the tilt lock is not down, right?

 

[LiquidCache]

Re: 1985 Johnson 150 GT questions/problem

No it's not down.

The wires for the T/T go into the front of the engine cover, and i have yet to remove it, so that's where i'm going to start when I get home.