First Impeller Replacement - Lower Unit in the Wrong Gear

Howdy,

I got a new boat about a year ago with a 2003 Mercury 150. I cranked the engine up for the first time this year, and it was not pumping water (it was on the trailer with the "ear muffs" on). So, I figured it was the impeller. Being a newbie boat owner, I found all of the articles and references very helpful.

I didn't have too many issues, however when I tried to put the lower unit back on, the shift shaft was not lining up. I've come to the conclusion that I did not put it into forward enough and I must've moved the lower unit shift spline while I was working on the impeller. Sooo, I put the control back into Neutral, and I grabbed some pliers and I am pretty sure I got the lower unit in Neutral. I did this by turning the drive shaft CW and watch the prop turn as I rotated the shift spline CCW. The prop would stop turning. As I continued to turn the drive shaft, the prop would go from stopped to reversed rotation. So, I put it back to where it was stopped when I would rotate the drive shaft.

I made sure the control was back in Neutral, and slid the lower unit back on. I had to rotate the drive shaft a bit, but it fit back on and I bolted it up. In Neutral, my prop free spins. In Forward, it is locked, and in Reverse it is locked.

My reason for this post is:
1) Did I go about getting the lower unit back in the proper gear correctly? Should I be concerned about firing up the engine? It seems like it shifts into gear a bit "tougher" (engine not running) than it was, but that could be my faulty memory.
2) I found a lot of misc comments about recovering from this, but it was all spread out. On the chance that I did it correctly, I figured it would be helpful. On the chance that I did it incorrectly ... hopefully I'll get some feedback.

Thanks in advance! -Jerod

Re: First Impeller Replacement - Lower Unit in the Wrong Gear

Well, I fired it up this morning and the prop appears to be changing gears properly.

My water pump still does not seem to be pushing enough water. After the engine is running for a bit, some water starts to be pushed through, but its not with much velocity.

Could this just be due to my "ear muffs", or do I have cause for concern? Could the lower part of the impeller be messed up?

-Jerod

Re: First Impeller Replacement - Lower Unit in the Wrong Gear

jrb, are you letting the motor warm up to operating temp? Your Merc has thermostats ahead of the telltale that will restrict most of the flow until they open (143*). Once warmed up, it should have a nice steady stream.

And, yes, you could have less-than-optimal water pressure on the muffs or there could be leaks in the water pump housing. Good Luck

Re: First Impeller Replacement - Lower Unit in the Wrong Gear

Thanks! That did the trick. I guess I was being too big of a chicken and was afraid I was going to overheat the engine. I probably didn't need to change the impeller anyways. Oh well, a little preventive maintenance won't hurt, and now I know more about my Merc!

I've shifted the motor in and out of gear while it was running, and I noticed that when I put it back into Neutral, the prop was rotating in the forward direction slightly. Do I need to drop the lower unit again, or is this nothing to be concerned about? -Jerod

Re: First Impeller Replacement - Lower Unit in the Wrong Gear

And it was not just rotating because of inertia. I would go from reverse to Neutral, and it would be a slow forward rotation. -Jerod

Re: First Impeller Replacement - Lower Unit in the Wrong Gear

Thats normal I have a 90 and when I run it in a barrell in neutral it spins slow.

Re: First Impeller Replacement - Lower Unit in the Wrong Gear

Thanks for the help guys! - Jerod