Changing Merc propshaft

[vector mike]

What's involved in changing a propshaft on the old style preload pin LU's? Do I need any special tools to remove the carrier or the propshaft? Do the gears have to come out? I see where it is a 2 piece shaft and I have heard that you can replace it with a 1 piece. Is this true? What is the 1 piece propshaft out of that fits in this LU? The shaft has been bent ever since I got it and I think it is time to change it now. Never had to mess with the LU before. :o It doesn't leak a drop of oil and doesn't have any vibration so I really hate to mess with it but I think it needs to be changed. Would you guys just leave it alone or change it?

[dez nuts]

change it that case does not have a 2 peice shaft and yes you need some special tools to change it you need a spanner nut tool and carrier puller and a shift shaft bushing tool and a tool to put the pin back into the clutch if you are reuseing it it;s probally not a job for someone that has never done it or has no training in this type of work thats my 2cents keys dave:rolleyes:

[vector mike]

I used to be an automotive machinst machining and rebuilding all types of engines. I have rebuilt many 1cyl through 10 cyl 2 and 4 stroke engines, automatic and standard transmissions and rear ends. I went to school years ago for just that. Doing a little lower unit seems cake compared to automatic transmissions and setting up rear end gears. Now I mostly just sit behind a desk in the engineering dept and do the dirty work as a hobby. I was just wondering about the tools and if it really needs to be done. ;)

[shooter1]

Taking the propshaft out is no real problem, you will need the spanner nut tool and the shift shaft bushing tool and a puller. I made my puller out of a Harbor Freight puller and took and bent some 7/16" allthread for the legs. I have used Cy at NEECA to straighten prop shafts before and is super to do business with. You don't even have disassemble the shaft. He also does it cold. You need to check the bearings to make sure that there aren't any fixxing to give you problems. Also if you aren't replacing with a NEW shaft you might not be fixxing the problem.

Shooter1

[vector mike]

When I got the LU I was not well informed of what it should look like. This was before there was S&Fand all the info I have learned here. This was a number of years ago. The guy at the boat place said that all propshafts have a little twist in them after time. Well upon further observation after I removed the lower to change the water pump about a year later I noticed the driveshaft had the "twist" in it too. So I assumed somebody got something stuck in the prop while running to put this twist in both shafts. I then checked the propshaft for runnout and it had it. I don't remember how much it was but it was enough to concern me back then. I have since just ran it expecting it to vibrate or leak or at the worst, break off, but nothing. So I am doing this just becase I think it should be changed. Not really sure if it effects the performance being a little bent or not.

[marshan162]

I just finished a rebuild and got away without buying any tools, If it's a preload pin type it probably has 'Camshift' type selector. if that's the case, you don't need to remove the shift shaft.
My carrier nut wound out with a soft drift.
You can pull the carrier with the aid of a couple of wooden blocks and an old 'through hub exhaust' prop, by using the prop nut.
And thats as far as you need to go to get the prop shaft out, you leave behind the shift shaft, cam, forward gear and pinion. If you need more detail let me know

The only thing i would add is that you should torque the carrier nut back up when reassembling, so without the tool you will have to take it to a someone who has one. But that can be done while on the boat.

I'm going to make a tool from the steel body of a car starter motor. It's just the right diameter

If you need more details let me know

[vector mike]

What type of starter motor are you using? Sounds like a piece of cake. I can make one of those tools pretty easy.

[M.CHAPMAN]

Not all of the pre-load cases used the cam shift. Some of them have the other shifter that will require the removal of the shift shaft from the case. You will have to make sure the cam stays in the neutral position in order for the propshaft to slide out. I just did one a few weeks ago and it had the later style shifter in it. If you remove the bearing carrier and the propshaft does not slide out with little ease then you have the later style shifter.
-Michael

[marshan162]

What type of starter motor are you using? Sounds like a piece of cake. I can make one of those tools pretty easy.

It was one i found lying around, even if i new what it came off it would probably not be a great help as it is european.
Basicaly the idea is to use the main body of the motor where the field coils are fitted and remove all the junk from inside. Turn up a disk of steel to weld inside, that has a hole in the centre to slide over the prop shaft as a support. then either weld on the end some 1/4 inch squre stell bar pieces , or cut the end in a castellated manner to match the carrier nut. Then all that is needed is a 1/2 square drive welded to the other end. What material you have to hand is the biggest decider on how you do this

the good thing about the starter bodies are they are very thick wall thickness, thicker than any tubing I could find.

[dez nuts]

that tool is very inexspensive it sounds like more work to make it than just buy the right tool my 2 cents

[marshan162]

Not all of the pre-load cases used the cam shift. Some of them have the other shifter that will require the removal of the shift shaft from the case. You will have to make sure the cam stays in the neutral position in order for the propshaft to slide out. I just did one a few weeks ago and it had the later style shifter in it. If you remove the bearing carrier and the propshaft does not slide out with little ease then you have the later style shifter.
-Michael

I wasn't too sure if all preload drive units had Camshift or some had Ezeeshift. the one you had last week maybe like mine is now. I changed the casing due to skeg damage. The only reasonable case I could get was the newer Ezeeshift type so I converted it. You can tell if you have Camshift or not by turning the prop backwards in forward and reverse. One type will ratchet in both gears the other type will only ratchet in one. I can't remember what way round though. So i don't want to say now, but I cant tell you later

Karl

[marshan162]

that tool is very inexspensive it sounds like more work to make it than just buy the right tool my 2 cents

I can see your point, it may be inexpensive in the states but everything from Mercury is expensive in the UK and difficult to get hold of. Example the 2 small propshaft seals shift cam and the large 'O' ring in the UK £35 = $66 ignition coil about £50 = $95 each. My nearest suplier is about 35 miles away so add carriage. He probably won't have it in stock so add a week for delivery, 2 or 3 if its not in the country. I have a lathe and a welder so it's not really a big deal to fabricate bits as I go along

Karl

[marshan162]

Mike you may already know this, but you can tell wether you have Camshift or EZshift as follows
Shift unit into reverse If you can rotate prop in reverse direction and it rachets you have EZ****. If not its Camshift. If you have Camshift you do not need to touch shiftshaft to remove propshaft