1973 Mercruiser 140 shift cable adjustment.

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Aug 19, 2016
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I'm the new owner of a 1973 Starcraft Holiday 18. She's not pretty, but seems solid.

Starts easy and runs great all day, but stalls when you try to shift into reverse.

My local marina quoted me $340 to replace the lower shift cable. That's 3 hours of labor at $75 an hour, plus the parts.

Is there a procedure I can follow to try to adjust it myself before replacing it?

I own basic tools, and am willing to learn, but I'm no mechanic by any stretch of the imagination. I live near a large lake, but have never owned a boat and don't know much about them. This boat was given to me by a friend that only owned it 1 season, than had to move out of state.

Thanks!
 
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Texasmark

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Why do you think it's a cable problem? Idle too low with remote control in N.? The shift cable does nothing for or against moving into R vs F gearing when you are experiencing an engine killing event. If the cable moved you there it's doing it's job. What you may be experiencing is a problem in your lower unit gearing that is binding, thus loading the engine and causing it to stall!

On that year model boat, first thing I'd do is to check the condition of the outdrive lower unit oil. Drain a bit out and have a look. If blue/black fine. If any other color or if it has bubbles, or if water comes out first you have a leak and that and the water may have corroded gearing causing your problem.

I had a '65, 18' Holiday I/O I restored years ago. Loved it.
 
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Texasmark -

Thanks for the reply. The reason I suspected the shift cable is...

I called the marina/ Waconda dealer on the lake where I live. They told me they don't work on boats that old and advised I call a boat repair shop 60 miles away that specializes in older boats.

I called them and described the problem over the phone and they told me that is sounds like the lower shift cable needs replaced, and gave me the $340 quote.

I'll check the condition of the oil today.
Thanks!
 

Texasmark

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Marc C has a good idea but since we started this, let's have a look at the lower unit first. I completely restored my outdrive, including using JB weld to reconstruct cast aluminum where age and corrosion ate it away....on a sealing surface no less. I am not naive with respect to the older Mercruiser outdrive. Mine was so old it didn't even have power trim.....tilt was it and for what the outdrive weighed, with no counterbalance (like with the powerhead of an OB engine) it was a dog to lift.

I learned how the CV joint really worked where the drive shaft enters the outdrive.....if it isn't balanced, any turning to either side started the drive line vibrating and the farther you turned, and the higher the rpms, the worse it got. I was strapped for cash and thought I'd replace the worn bearings with generic bearings form the auto parts store........wrong.
 

Texasmark

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Ok thanks! Are you moving the thread or should I start a new one. I've got some photos of the drive oil and other stuff now.

It's not my idea to move it. I like it where it is because this is the forum I frequent. I no longer have my Starcraft and hence no need to frequent the Mercruiser forum. As I told you if we get bogged down, I'll flag an Administrator and they will be able to move it to ensure that you get tour problem solved.
 
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It's not my idea to move it. I like it where it is because this is the forum I frequent. I no longer have my Starcraft and hence no need to frequent the Mercruiser forum. As I told you if we get bogged down, I'll flag an Administrator and they will be able to move it to ensure that you get tour problem solved.

Ok thanks.

I've been out on this boat a few times with my friend. It would never shift into reverse, the engine would die as soon as you shifted into reverse. Forward it was fine.

I bought some muffs today and hooked them up. I started the boat for the first time since it was given to me. It fired up quickly and ran great.

It DID NOT DIE when I shifted into reverse. It ran fine forward and backward. How could this be?

The only problem I had, was I couldn't get the tilt/ trim to work. It makes noise like the pump running, but no movement from the drive. This was not a problem before.

I drained a little oil out of the bottom of the drive. It was black and greenish. No bubbles, or water that I could tell. If I figure out how to post a photo I will.
 

Texasmark

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Oil: I don't need the picture. What you said is fine. Consider the LU ok for the time being.

It's always a good idea to change the gear lube every year if you run a lot or every other year if you don't. The Oil is Quicksilver/Mercury Premium Lower Unit Gear oil. Being an I/O you may want to look for the notation, Mercruiser Suitable. The lower unit of a Mercruiser and a comparable hp outboard are just about identical so I don't see why they offer/may offer a different oil for you. May not. read the back of the bottle. Walmart sells the oil in the quart container in a package which contains the oil, engine adapter, hose and pump...real convenient. I boats sells Seloc service manuals. Go to the top of this page and look in Boating Parts and Accessories. You can purchase one or just rent time on the internet. I rented mine and I had it as soon as I paid for it and it worked great for me. Pages copy very well.

Woundn't shift on the water and does on land:

Mechanism, mechanism, mechanism......that's how I trouble shoot. What is different about the two? Off the cuff, nothing. Gotta dig a little deeper.

Since you are new to your boat something you need to know. Get a helper to do the shifting, engine off, and you get your hand on the propeller.

Shift into F gear. Grasp the prop and turn it CW. It should make a clicking sound. Attempt to turn it CCW. It should resist. This is the overrun clutch in the lower unit and allows the engine to drop in speed, like when slowing down from WOT, the water is turning the prop faster than the engine is running. The propeller and prop shaft will move forward and backward slightly as this happens.

N gear if free spin both ways.

R gear is usually a different gearing setup. Square cogs and slots, no overrun clutch. The cog has to be aligned with the slot for the shifter to slide into the gear. The service manual cautions that you should NOT shift into R gear unless the prop is being turned manually while shifting, or the engine is running.......they caution that the shifting mechanism (including the cable to the remote control) can be damaged.

Now shift into R gear: You grasp and turn the prop either direction while the helper shifts into R slowly. Once in gear, notice it is locked in both directions.

Did someone try to shift into R during your water testing with the engine off where you said it wouldn't?
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You and your helper change places. Tell them what you did so that they can repeat the process. You grasp the control and without a lot of force, nudge the control toward the rear feeling the resistance till the gears get lined up and the control moves all the way in gear.

Last, have your helper go back to where the shifting cable is attached to the outdrive. CAREFULLY test it both with the gears lined up and deliberately misalign them and check for any bending or distortion in the cable end or the shifter lever and note the difference between the two as to how the control feels.
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On PTT you have no power, dead motor, no/low oil, stuck valve, frozen pistons. Follow the hydraulic lines from the cylinders back to the pump/sump. Push the up or down button and listen for the pump to run. If it doesn't chase electrical. If it does, chase hydraulic.
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Once you have answers to this tell me what happened.
 
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Ok thanks, I will try that.

Can you explain to me how the PTT controls should work?

I have a 3 button vertical panel. The middle button is divided in half by a line . From top to bottom they are labeled up, up, out, in. The middle button has both up and out labels, and is divided in half by a printed line.
 
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Texasmark

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The Mercury Power Trim & Tilt (PTT) has both trim and tilt functions. Tilt is full range and used for very low speed operation as it has a "low pressure" pop-off valve. It will raise the outdrive to where the lower part of it is either out of the water or barely in it. The trim part has a limited range with a "high pressure" pop-off valve. Trim is like -4 degrees from vertical ("IN"), lower unit tucked in near the boat, out to about 20 degrees from vertical ("OUT") away from the boat. If you are in the tilt function and exceed the pop-off pressure by advancing the throttle too far, the lower unit will move toward the "transom" (vertical board to which the outdrive is mounted) till it gets to the upper set point of the trim function where it will stop, about 20 degrees out.

Does that help?

Tilt is used for shallow water operation and beaching. Trim is used for boat attitude while underway on "plane" (boat moved from in the water to on the water and the bow came back down (somewhat, depending on speed).

Trim IN for the bow (front of the boat) to plow....dig into the water, like when running fast in a good chop sticking the bow down allows more of the hull to cut the wave rather than bounce over it. However plowing makes steering difficult and reduces boat speed due to the extra drag of more hull in the water. This position also helps to get on "plane" by helping to get the transom up so the speed can increase.

Trim out after you are under way and want to maximize your speed/mpg. You can just trim out while watching your speedometer for the best trim position. Once you get it get your finger off the button. When the trim gets to it's max position, holding your finger on the button will not make it go any higher.
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"It is possible that someone tried to shift into reverse with the engine off."

Now that you are getting more familiar with all this, yes and that may be why the marina suggested that you needed a new cable....aka a kink in it. It's a common mistake people make when they don't know what I told you about R gear shifting herein. You should be able to inspect it and look for a sharp irregularity, especially with the center cable. Once kinked, very hard to effectively straighten back out. The reason I added what I did to my previous response about CAREFULLY trying to shift with the prop not turning nor the cog-slots lined up was to possibly expose the smoking gun....kinked cable.
 

Chris1956

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A bad lower shift cable will often cause the motor to stall when shifting into reverse. Mercruisers have a shift assist switch that kills the ignition when shifting. If the engine shifts easily, the shift assist switch is not activated. If the cable or the shift linkage binds, the shift assist switch kills the spark.

You should be able to install a new lower shift cable, but it is not straightforward on how to do it. I would recommend a service manual, as you need to go step-by-step. You will likely need to replace the shift cable bellows, as it is likely bad.
 

Alumarine

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Feb 22, 2005
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As chris1956 says it could be the lower shift cable.
There is a reason it shifts differently in the water and out of the water. No load versus a load through the prop.
That can cause a worn shift cable to behave incorrectly.

In any case if you PM a mod they can move this over. It might help with ongoing problems for it to be in the mercruiser forum.
 

Texasmark

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A bad lower shift cable will often cause the motor to stall when shifting into reverse. Mercruisers have a shift assist switch that kills the ignition when shifting. If the engine shifts easily, the shift assist switch is not activated. If the cable or the shift linkage binds, the shift assist switch kills the spark.

You should be able to install a new lower shift cable, but it is not straightforward on how to do it. I would recommend a service manual, as you need to go step-by-step. You will likely need to replace the shift cable bellows, as it is likely bad.

Thanks Chris. Looks like all the fingers are pointing in the same direction. So far so good.
 
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As chris1956 says it could be the lower shift cable.
There is a reason it shifts differently in the water and out of the water. No load versus a load through the prop.
That can cause a worn shift cable to behave incorrectly.

In any case if you PM a mod they can move this over. It might help with ongoing problems for it to be in the mercruiser forum.

I hated to hear that! I was really hoping the shift issue magically fixed itself!

It's been raining here a bunch, but I'll try to get some more investigative work done soon.

It sounds like the PTT pump is working, so could just low fluid cause the drive to not move? Which I suppose would mean a leak somewhere. There is no fluid in the well under the engine.

It looks like previous owner did work on this boat. The engine is pretty clean and it starts right up. Drive has new looking braided stainless lines, and the drain plug is a new hex head plug.

Who can I PM to move this thread to the correct forum?

Thanks!
 

Alumarine

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I hated to hear that! I was really hoping the shift issue magically fixed itself!

It's been raining here a bunch, but I'll try to get some more investigative work done soon.

It sounds like the PTT pump is working, so could just low fluid cause the drive to not move? Which I suppose would mean a leak somewhere. There is no fluid in the well under the engine.

It looks like previous owner did work on this boat. The engine is pretty clean and it starts right up. Drive has new looking braided stainless lines, and the drain plug is a new hex head plug.

Who can I PM to move this thread to the correct forum?

Thanks!

Low fluid would be a problem.
If you go through a couple of other threads you should find a user that is a moderator. Just PM one of them with a link to this thread.
 
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The PTT fluid is very low. I checked it with a wooden skewer in the fill hole and there was only about a 1/4" on the bottom of the stick.

The fluid was clear, but certainly oily. Not as thick as motor oil. Didn't look reddish like ATF. What does actual PTT hydraulic fluid look like?

I googled it and it looks like some tractor companies use a clear fluid that is near impossible to see on the dipstick. That's how this stuff was. Since I live in tractor land that might make sense.

Any thoughts, should I stick with the same? Should o drain it and use something else? If so how do I drain it?
 
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