Preload pin lower unit.

[skialot2]

I am looking at buying a lower unit with a preload pin. It has a nose cone installed already. It has been disassembled and inspected. The guy said he found worn gear ramps. Are preload lower units good? Is it easy to get parts for them? Thanks

[tlwjkw]

we ran them for a very long time when thats all there was... not very many problems that i remember but we ALWAYS had "start in gear" with anything we ran.. we were pretty hard on 'em with some big compression and really surfaced high 2.4's.. don't know 'bout tha parts situation.. wouldn't invest a lot in one now days though.. maybe for a spare....... jmo

[25two.stroke]

They are good, yes. Easy to get parts for...not so much.

[skialot2]

After doing some research I bought this lower unit pretty much sight unseen for $150. It has a 4 slot nose cone and a very professional looking torque fin Almost looks factory, but no way it is. Most of the internal parts are still available from Mercury except the driveshaft and the gears themselves. But you can get them on eBay. The guy said he never used it. He just took it apart and found the gear ramps were worn. There is some damage on the shift dog. But the ramps on this reverse gear do not look all that bad to me The forward gear looks about the same, maybe slightly worse I am going to finish taking it apart to clean all the dirt out of it. Change the shift dog with the good one I found in the box of parts that came with it. Put it all back together with new seals and hopefully I will get a few years out of it.

[skialot2]

After taking apart the rest of this lower unit. I have changed my mind. There is too much damage on the forward gear. It needs to be replaced.


Identifying the unit has been fun. I thought it was from a 200 but the part numbers don't match. I have been searching the parts catalogs trying to match up part numbers with the schematics. The only catalog the part numbers match is for the V-225. It was made in 1980-1981 only. It's an archive catalog. All the gears are listed individually. There is no listing for a set. So, I am only going to buy the forward gear... and the bearing...and I am gonna need a shim kit... and all the seals. Exc. Exc. Exc.

[skialot2]

Happy New Year Everybody!

Trying to find somebody to work on a preload pin lower unit is like finding someone to sleeve a 2 stroke block. I had to do it myself. The forward gear had a part number on it. I searched for it online. The description for the gear said it was for a racing engine. so, I assume this should be a pretty strong lower unit. I also got a new forward bearing and race. I don't have the proper tools, so I improvised. I pulled the old forward gear race and shims out of the case. Then I used a micrometer to measure from the back of the bearing race where it would hit the shims, to different points on the old gear face and compared them to the new gear. I came up with a .002 difference with the new gear being shorter. So, I added .002 to the shims. From .018 to .020 in shims. I replaced all of the seals. Put it all together and if feels really good when I spin and shift it by hand. Spins nice and smooth. Has a positive shift with a strong detent. I put on a new water pump including a new base. Aftermarket housing and gaskets but I used a quicksilver impeller. I'm going to put 5 or 10 hours on it next season, then check the magnetic drainplug for any metal shavings. If it's clean I should be good.

[skialot2]

I have a little mor than 10 hours on this lower unit. Most of it while surfaced. I checked the magnetic drain plug for shavings. Nothing out of the ordinary. However, I noticed it had a good amount of endplay in the propshaft. Looking closer the carrier is moving in and out. The carrier nut loose. Lock tab is still engaged. Tried to torque the carrier nut again. Got to 110lbs and pop. Carrier threads are stripped. Tried putting a brand new carrier nut on and stripped at 80 psi. Case is junk. Glad i didn't lose the prop.

[KIRCHNER]

They are good, yes. Easy to get parts for...not so much.

i like coming back to the ramp, click,click,click,click!