trying to remove lower unit on 2003 Merc 50 hp 2 stroke

robow7 · 08-24-2010, 05:03 PM

Hey gang, trying to remove my lower unit on my 2003 Merc 50 hp 2 stroke so I can change out the impeller as it's not throwing water any more while running. I've got the 5 bolts out and the unit has dropped about 1/2" but won't seem to come any further. I've got it in drive and but just wondered if the drive shaft is bound or what I'm missing here, first time that it's been off. Thanks for any suggestions you might send my way.

deer_predator · 08-25-2010, 03:23 AM

On my 30 I had jam nuts on the shift rod. once it dropps about 1/2" you should be able to see them.

robow7 · 08-25-2010, 06:00 AM

Ken,
that's exactly the problem. This morning when I got up and looked at the motor with decent sunlight, it became obvious. Is the bottom nut like a jam nut and the upper longer nut the one that will have to be most backed off? So would that be the lower nut turned just slightly counter clockwise and the longer nut above turned clockwise to disconnect the linkage?

Bowfisher5 · 08-25-2010, 06:34 AM

Rob;
Several "How to " articles when I Googled "Impeller change 2003 Merc 50 hp 2 stroke" I also have a lower unit for 2003 Merc 50 hp 2 stroke if you need one or if you would just like to have a spare on board.

Dave R

robow7 · 08-25-2010, 06:58 AM

Dave, yea, the way my luck has been lately, I need a second and a third lower unit and toss in an upper unit as well. I sat out in the middle of Lake Shelbyville on Monday morning tied up to a tree for an hour while I worked on both my main trolling motor and my back up that I carry with me only to realize it was definitely in my wiring. Finally got it fixed, only to run further north up Wilbourn Creek and then realize I'm not throwing water. Long slow ride back to the ramp via my trolling motor. Oh did I say that not only did my reel not function properly right off the bat but 2 of 3 back up reels wouldn't function as well. I just about pulled out the bottle (of which I hate) but then found a reel that worked only not to find many fish to shoot at. ARGHHHHHHH!

deer_predator · 08-25-2010, 07:22 AM

I am pretty sure the bottom is the jam nut and the top is the rod. I have always put mine in reverse while changing out the impellers.

HNI_Christine · 08-26-2010, 06:43 AM

Sounds very similar to the little Honda I used to have. It went through soooo many impellers I actually got good at taking the lower off.

On the shift linkage, the thin nut is just a jam nut to keep the long (coupling nut) from moving with the vibration.
Like Ken said put the shift lever in reverse and it will be easier to get to the linkage.

robow7 · 08-26-2010, 08:01 AM

Thanks for the info and help. I got it changed out yesterday with little problem. It's streaming out quite well now. What I didn't find out until I was almost done was that somehow (my friend speculates it was a mud dobber) my hose within was caked with mud inside and also prevented it from releasing. The 7 year old impeller really didn't look in bad shape so the blockage was probably more the problem but it didn't hurt anything with replacing the impeller for sure. My friend has it had happen so many times that he actually keeps a wire in his release hole so as to prevent the insects from getting up in there when boat not in use. It seems pretty small to me but what do I know.