Lower unit troubleshooting steps-- the basics

[juels98]

Hi,

Please bear with me-- I'm looking for some basic steps to troubleshoot my issue. I think it should be pretty easy to diagnose.

I have a 1993 3.0L LX Mercruiser 4 cylinder I/O with I think an Alpha One outdrive.

After having my boat sit winterized for 3 years, I was ready to get it back in use. Lots of forums suggested that the impeller would need to be replaced since it sat this long. So, I watched a bunch of videos and read some sites, and replaced the impeller. I then went to start the boat and it wouldn't. After some troubleshooting and forum help, I narrowed it down to a fuel pump. After a couple months, I replaced the fuel pump and did a tune up and the engine ran. By that time it was late September and I winterized the boat again. However, once the engine ran, I tried testing my work and the new impeller worked great-- running on muffs, the water shot out just like it's supposed to out of the holes. Engine ran great. However, when I put the engine in forward or reverse, the prop doesn't spin-- it kinda freewheels.

Some things to keep in mind:
1. From what I recall, I put it in forward gear before dropping the lower unit and kept it there until all was re-assembled.
2. The shifter has no issues going in to the forward and reverse gear
3. I don't remember why, but I had my buddy push on the prop while the engine was off and I put it in gear, If I recall, the prop wouldn't move, but with a little force it finally did-- my logic may have been trying to move the motor via the prop to see if all works-- don't remember-- sorry. The point being, maybe we spun the prop hub?
4. Could there be a cable or something that I didn't fully hook up? Any photos would be helpful. I've attached a photo I found of when the lower unit was pulled off-- for reference. From what I recall, it went back together pretty smoothly.

So, seeing that engine runs, lower unit kicks water out, able to shift in to forward and reverse but the prop doesn't spin-- what are some things for me to look at? I'm about 90% sure it's a re-assembly issue or the fact that we put force on the prop while it was in gear engine off.

Thank you for your help in advance!
Julian

 

[juels98]

Same photo-- different orientation

 

[ThomW]

If you have the shifter in forward, and it is engaged, the prop should not spin in one direction, but spin in the other. Same for reverse gear, but with the opposite directions. If you have shifter in gear and the prop spins in both directions, it wasn't lined up right when you put the lower unit back on. I seriously doubt you spun the hub, by just applying some pressure to prop by hand.

After your friend tried turning the prop, it spun? Was it then spinning freely in both directions? While in gear? Does the prop lock when shifter is in gear now or not?

 

[ThomW]

When replacing the lower unit, even a slight bump or turn of the prop can knock the lower unit out of forward gear. If the prop now spins freely in both directions with shifter in forward or revers, you need to drop the lower out again. That metal "L" piece in the pictures is the shift rod for lower, by turning that, you can get lower unit back into forward gear.

 

[Bt Doctur]

Being a GEN II its almost impossible to mess up. You could have missed the roller in the shift arm when you installed the drive

 

[juels98]

Helpful video.

 

[juels98]

well, my last post didn't work-- sorry about that.

ThomW-- I think you may be right because I don't remember locking the prop when installing the lower unit back up-- so it probably jumped out.

I'll try and troubleshoot this weekend if I can find some time-- should be warm-- I'm in MN. Just need to unwrap her

Thanks for all your advice!

Julian

 

[Bt Doctur]

why not simply raise the drive and look

 

[juels98]

Just a quick followup, I had some time this weekend to take a look. I put the boat in forward gear and went to spin the prop by hand. It spun in one direction and would lock in the other. In neutral, it would spin freely in both directions, and in reverse, it would initially spin in both directions though not as freely, I went to the lower unit and used my finger to push the "L" shaped shifter to the end of its travel and the rear gear would lock too, allowing the prop to spin in one direction not the other. If I recall, in forward, the prop would spin CCW and in reverse CW but don't quote me on it.

Anyway, I'd like to get the boat started and verify again if the prop spins, but it's early spring yet in MN-- we could have frost any time, so I"ll wait a few weeks to summerize the boat. Will be back to update-- unless you guys can suggest anything else for me to check in the mean time without starting it up.

Thank you!
Julian

 

[Luv2fish36]

It sounds like you have forward and neutral but reverse just needs adjustment. Put in reverse go to your shift bracket on the motor, at the shift cable end, (not the remote shift cable end) loosen the slide bolt with a 7/16 box wrench and slide it up in the slot just a litlle bit. This will give more reverse. Go to far and you'll trigger the shift interrupt.

 

[juels98]

Thank you everyone for your help! Once the weather warms up and I get the boat started, given what I've seen so far, if I put it in gear and the prop doesn't spin in any direction-- are there any other troubleshooting steps that anyone can think of? What else could cause the prop to not engage?

Thanks,
Julian

 

[Bondo]

What else could cause the prop to not engage?

Ayuh,.... Considerin' yer able to manually shift it into gear, the shift cable adjustment is the only thing,....

 

[juels98]

Thank you. Sure hope it's that easy!!! I'll update once the weather warms up.

Julian

 

[juels98]

Thank you everyone for your help. Just to provide closure to the thread, I got the boat running last night for the first time in 2 years, adjusted the carb once it warmed up and it idled around 800 RPM. I then put the shifter in forward and the prop spun, I tried the rear and the prop worked as well.

Now, all I need is to get her vacuumed and washed/waxed and put her in the water.

Thanks again!
Julian