1993 Johnson 150 Tilt/Trim Rebuild

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1993 Johnson 150

Silver Star Series

Tilt/Trim Rebuild

I happened by the rear of my Ranger the other day and saw oil all over the lower unit and the tilt/trim. The tilt/trim unit was leaking pretty badly. I tried to run it up, but it move very little before gurgling badly. Most of the oil was on the ground.

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It had leaked a couple of years ago and I put ins some ATF which got it to work until now. Maybe the cold weather helped it fail? Anyway, I want to fish soon so it has to be fixed. I looked on http://www.bbcboards.net/ for help but did not find a detailed rebuild thread with pictures. I also tried YouTube. So, I posted this information to the BBC site as I did the rebuild. I asked for help and they responded with some great advice. You can see it on BBC too at http://www.bbcboards.net/showthread.php?t=872001 . I also referred my Seloc manual on Johnson engines during the rebuild.

I began a couple years ago to gather parts and a tool to work on the unit, but never did the rebuild then. I did purchase the seal kit but I cannot find where I put it so I would not forget where it was put. That is going to cost me another $86 for a kit.

I also bought a special tool to take the ends off the cylinders. The one I bought was an OTC Gland Nut Wrench 7463 from Summit Racing.

It has 1/4" and 7/32" pins, adjustable diameter and works with a 1/2" drive ratchet. I was not sure it would work, so I tested it when I bought it. I was concerned about the strength of the tool being adequate to remove the cylinder caps since they had never been removed. But, I was able to loosen both trim cylinder caps without issue. I drilled out by hand two of the holes on the trim cylinder caps to allow the 7/32" pins to be used.

Then I found that the pins are held in by set screws. So, I could have just made some new pins of the proper size from a drill bit and used them instead of drilling the caps. That would have been much easier. I was able to get the trim cylinder caps loosened without removing the unit from the engine.

I also found that the unit had to be removed to get to the cap on the lift cylinder. That is when I decided to try the ATF to see if it would help the unit reseal itself.

Yesterday my brother and I removed the unit. We followed the instructions in the Selco book. When it described removing the wiring, it did not give pictures or clear detail of what the connectors looked like. We just followed the lead coming in from the bottom of the engine cover and disconnected all of them to allow us to get the wires out of the hole. One of the connectors is too large for the hole and the wires must be removed from the connector.

Then all the single wires are pulled out of the lower engine cover hole. Now the hole is just barely big enough for the rubber connector that connects the trim limit switch to be squeezed through. It was a very tight fit. Now the wire loom can be removed.

We put a hoist onto the lower unit and used it to raise the lower unit and hold it securely while we removed the unit.

The ground wire attached from the engine mount has to be removed from the pump housing using a 10 mm socket. The trim limit switch has to be removed to allow the wires to be removed from the hole in the engine mount.

Then the engine has to be high enough to allow the lift cylinder pin to be removed. Now the lower pin can be removed. This engine is very clean so the pins just pushed out without issue. we also found that the travel limit pin has to be removed to get the unit out. The rubber coated connector in the picture is the one that does not come apart but will barely fit through the lower engine cover hole. (Well, I stand corrected. The connector will come apart per input from a forum member. We just had to make a tool. See how we did that in the install section.)

The safety support had to be raised back up while we removed the unit. Then we lowered it and lowered the engine back onto the safety support since it will be several days before we put it back on. The rest of the day was spend driving to a dealer to get the seal kit and some oil.

Snow and very cold temps are expected over night and all day tomorrow. Maybe I will be able to get to cleaning the unit and draining it so I can bring it inside to do the rebuild.

The safety support had to be raised back up while we removed the unit. Then we lowered it and lowered the engine back onto the safety support since it will be several days before we put it back on. The rest of the day was spent driving to a dealer to get the seal kit and some oil.

Snow and very cold temps are expected over night and all day tomorrow. Maybe I will be able to get to cleaning the unit and draining it so I can bring it inside to do the rebuild.


18 degrees this morning and still snowing. The wind is picking up and the temp is still falling. I will have to find a tub and bring it inside to clean it and work on it.

It is lunchtime and still only about 20 degrees outside. That is cold for middle Georgia!

I am glad we went out to get the parts yesterday. I am not going to play bumper cars with the other drivers out there. The part number for the o-ring and seal kit we got is 0434519. We bought some Johnson Tilt/Trim Fluid also.

I brought a bucket into the laundry room and washed the tilt trim unit in it with dish washing soap and warm water. My wife is aggravated by a spot of grease I got onto the floor.

I even cleaned out the wiper grooves with a toothpick. It is now pretty clean. No dirt and grit anyway.

Here is a better picture of the wires and connectors still attached to the unit.

I removed the nylon bushings which seem to be in decent condition except for the lift cylinder ones. One of them is cracked. So, I looked online at Boats.net and found them. I will be making another parts order but I will wait until ready to reinstall it before ordering.

I also found that the boat is a 1994 but the engine is really a 1993 based on the model number. I think I already knew that but CRS kicks in often now.

I read the overhaul instructions during lunch. According to the instructions, I need some Evinrude/Johnson Locquic Primer and Evinrude/Johnson Nut Lock to put onto the lift piston nut and rod threads. I was advised that blue Locktite would be an acceptable replacement.


Yesterday after cleaning the unit I took the it outside to drain the oil from the reservoir. I am glad I did! Apparently, it was pressurized since we had to push the tilt cylinder down when we removed the unit from the boat. Oil sprayed out the cap when it was removed. To keep oil out of the house, I put a piece old plywood over a big box for a work table in the house garage and used an old cooking tray to catch any spills while I remove the cylinders.

The reservoir had to be removed first to allow for removing the tilt cylinder cap so the gland wrench would work. The small bolts are actually 3/8" and not 10 mm as I thought.

The instructions said to then remove the filter plug with a 6 mm Allen wrench.

The filter had to be pulled out carefully with a pick. It is in good shape and I will clean it before reinstalling it.

While the instructions listed removal of the pump and valve body next, I am thinking I will not remove those parts at all. They show no signs of leakage and seem to be working properly for now. The instructions say there are no serviceable parts in the valve body anyway. Also, I assume I can replace them at another time if needed. I am considering flushing the old fluid out with new fluid by temporarily installing the reservoir and adding some fluid. But I don't know if that will do any good, so I am still considering if flushing the pump and valve body is really necessary.

I removed the tilt cylinder cap and piston next. The 1/4" pins on the gland wrench fit perfectly for the tilt cylinder. I took the unit back outside to fully remove the cylinder cap so if any pressure remained, I would not spray oil all over the garage. There was no more trapped pressure.

The gland wrench would not fit at 180 degrees with only two of the holes drilled in the trim cylinder cap on one side. But since the cap was loose already, I was able to only put one pin in a hole and ease the cap anyway. I will drill the other two holes in the trim caps once the caps are removed for new seals. Otherwise, the gland wrench worked great.

There were no obstructions on the other side and the cap came out smoothly.

I unscrewed the caps on both trim cylinders. Once the cylinder caps are slid up the rod, there is some oil to drain and more to drain when the piston is removed from each cylinder.

You may notice the "L" I scribed into the cylinder cap. I put an "R" on the other one when I removed it. I don't know if it matters which cylinder they go back in, but I am going to keep the parts sorted until they are reinstalled.

After draining the oil and wiping the cylinders out, the cylinder bores looked good. There was some black sooty substance but it wiped out with the oil.

Notice the flakes of paint that kept chipping off the unit and parts. I was very careful to keep them out of the cylinders. I held the unit up while removing the loose paint with my pocket knife. I am sure a paint chip will cause problems if left inside the unit.

I will have to make a wood block for use in my vise out in my shop. That can wait until it warms up a little today. It is supposed to be 46 degrees this afternoon.

I took the three pistons and rods out to the shop to remove the nuts from the rod ends. I did not stay but long enough to loosen the nuts. It was 25 degrees in the shop and my fingers got frozen stiff.

Anyway, first I measured the trim rods to be 0.698" diameter.

Then I took a block of poplar wood and drilled an 11/16" and a 3/4" hole and cut the block in half. It turns out I did not need the 3/4" hole.

The resulting two block's 11/16" hole was used to hold the trim rods securely in the vise while I used a 3/4" wrench to loosen the end plates. It took a quick rap with a hammer on the wrench to loosen them, but both came loose.

Then I placed two small poplar wood blocks in the vise to sandwich the end of the tilt cylinder while I removed the 15/16" nut on the rod end. Again it took a quick rap with a hammer on the wrench, but it came loose too.

Now I have the parts laying on the kitchen table waiting for new seals while my hands warm back up.

I will get back to them after lunch.

I rebuilt the lift cylinder piston and rod first. I used a pick to remove the large O-rings on the cap and piston.

Next the nut at the piston end was removed to allow removal of the piston and cap.

There is an O-ring between the washer and the piston that has to be removed also.

I was very careful to not allow the springs to fall out of the piston. There is a plunger and small steel ball under each spring. The springs, plunger and ball that must be reinstalled in the same hole later.

The lift cylinder cap wiper seal was removed with a screwdriver.

A pick was used to remove the rod seal from inside the lift cylinder cap.

I installed the new O-ring and wiper seal into the cap. The wiper seal is installed with the lip pointing out. I was able to press it in by hand.

Next I started removing springs, plungers and balls from the piston. I marked the first hole and the second one too so I would remember the direction to go to reinstall all of them. I laid all the springs, plungers and balls in a row.

The piston and each spring was cleaned and then the parts reinstalled in order of removal.

I wrapped some scotch tape around the rod threads and lift cylinder cap to allow me to install the O-rings without damaging them.

Next I just slid on the washer and put the nut on loosely. I will torque the nut later out in the shop.

I replaced the seals on the trim cylinder pistons and rods. Basically I used the same process to replace the trim cylinder piston and rod seals. Some of the trim cylinder seals are different types.

This is the trim cylinder cap wiper seal.

This is the rod seal that goes inside the trim cylinder cap.

After cleaning the trim cylinder caps, I took them out to the drill press to drill out the all the holes to 15/64". That allowed the 7/32" pins on the gland wrench to fit much better.

I installed the trim cylinder cap seals and wiper next.

The trim cylinder piston seal is not just an O-ring. It is a shaped ring and uses two thin plastic wipers.

I took all of the rods back out to the shop and used the vise to hold them while I tightened them. I used blue Loctite as ChampioNman suggested on the lift cylinder rod nut and torqued it to 65 ft/lbs. I just tighten the trim cylinder rod ends cy hand after putting a small drop of blue Loctite on them.

I then reinstalled the parts into the unit housing starting with the filter and plug. Then the trim cylinder rods were installed by carefully placing the piston end into the tapered section of the housing bores and wiggling them until the wipers slipped into the bore. It took a little finesse, but they went in finally. I left the caps loose so I could fill the cylinders with oil after the lift cylinder rod was installed and filled it with oil too. I just tightened the all three caps by hand for now. Sorry, I did not take any pictures of this,but it was pretty easy to accomplish.

I took the unit back to the shop and put it into my vise so I could properly torque the cylinder caps. I used 65 ft/lbs. on them which is within the torque range stated in the manual.

All that was left was to install the reservoir and O-ring. The three small bolts were torqued to 35 inch/lbs.

Now the unit is ready to install on the engine.

It may get installed tomorrow or this weekend. It will be warmer then.