Lower unit problems

crookedmullet

Seaman
Joined
Aug 21, 2003
Messages
58
I've got a 2002 200-hp 4-stroke. I took it to a local Yamaha service center to get it serviced. I received a call from them telling me that they couldn't get the lower unit off to replace the water pump. They had tried everything, even using a torch. I brought it back to see what I can do with it. I was able to loosen the back side of the unit(where the zinc sits) but I'm having problems getting the front side loosened. I don't see any linkages that may interfer with the unit coming off. The service center told me it's corrosion that's holding it together, which I don't believe cause I don't see any salt build-up inside. I've tried the screwdriver technique but that's causing more damage to the casting. Might there be a linkage that I'm not seeing or an easier way to take the unit apart? <br />If anyone has any new ideas, please let me know.
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: Lower unit problems

It's not the corrosion that you can see that creates the problem. The driveshaft must've corroded to the crankshaft. Saltwater will do that to you. That's why a 5 year old saltwater motor is a very old motor and a freshwater motor can last for decades.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Lower unit problems

are you sure they pulled all 8 bolts? there are 3 on each side. one under the trim tab and one fwd of the tab area. its the same style case as the 3.1 l v6. that 8th bolt has bit may a tech. I have seen one that wore the oil pump drive splines and got stuck. but never seen a properly maintained motor with that problem. properly maintaned motors you can always remove the t-stats,water pump,and pressure control valves.
 

crookedmullet

Seaman
Joined
Aug 21, 2003
Messages
58
Re: Lower unit problems

I pulled all 8 bolts, I'm not sure if they did. The back part of the lower unit is loose enough were I can see thru, I actually have a screwdriver in there, and I can't see corrosion. I also have a 1999 25hp 4-stroke engine and when I take the lower unit off, there is an oversize nut that connects the gear shaft. I'm wondering if the 200hp has something like that which I can't see. Is this a possibility?
 

lucky_strike

Recruit
Joined
Apr 18, 2005
Messages
1
Re: Lower unit problems

Assuming all of the attachment bolts are out, What is most likely keeping your lower unit from comming off is a badly corroded driveshaft support bearing that will not easily let the driveshaft pass through. I had this problem. The lower unit case would not seperate at all. I was advised that it had to be wedged off. I started with putty knives, then screwdrivers, then crowbars, and finally wood block spacers with the crowbars. Yes it will mar up the mating surfaces; after the unit is off just file them smooth as best you can. After the lower uint was off, the support bearing just broke out in chunks. Clean out the bearing cavity well, it will be full of corrosion and salt. Bearing is available at Yamaha dealer, I payed $60. Grease everything with waterproof grease upon reassembly.
 

crookedmullet

Seaman
Joined
Aug 21, 2003
Messages
58
Re: Lower unit problems

I was afraid I was going to have to do that. I appreciate all the feedback. The slow, tedious process begins. I hate saltwater for these kind of reasons, but the fishing is sure a whole lot better.
 

trackersocha

Petty Officer 2nd Class
Joined
Feb 19, 2005
Messages
192
Re: Lower unit problems

i disagree i catch plenty of crappie and catfish in the freshwater,. so , there!!!!
 

bigbrownbuku

Master Chief Petty Officer
Joined
Sep 17, 2004
Messages
885
Re: Lower unit problems

good luck mullet. when you get your gearbox off and everything lubed think about all the work you could have saved yourself with a gearbox removal every year. preventative maintenance is key in salt water. <br />now might be a good time to pull the t stats etc before the bolts holding them in seize also. if you have been to the same dealer every year for a service and they havent been pulling the gearbox as a measure of regualar maintenance you should be asking some questions.
 
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