Mercruiser MC1 drive (Pre-alpha) Rebuild

[s_explore]

Hello,

I have a little concern here. I just bought a new boat and the guy sold it to me without the drive installed. It's a 1978 wellcraft but had the engine swap to 1998 5.7L V8 Mercruiser, but the drive was not swap. I belive I have a MC1 engine, but I am really not sure.
Yesterday I did reinstall the drive and when I was going to activate up the trim cylinder one wasn't moving. Its stuck. So I removed the trim cylindee and dismantle it to see what is the reason for it not wanting to move. I found the guiding bushing (I think it's called like that) was stuck and didn't want to move. So I removed it with a vice grip. I've put something to protect the guiding bushing but it was so stock that I had to force it intensely. I made some mark on the guiding bushing, is it bad? Can I still use it or its garbage now.
If it's garbage does anyone know a seller which sells it. Also in what chemical can I put the trim to remove grease and everything?

Also other question, I have a compartment for gear lube on my engine and the hose exit the boat via the transom and I need to connect it. I am not sure where I need to connect it. I have an idea but I'm not 100% sure if you could help me with that.

Last question, is the MC1 drive interchangeable with an alpha one?

Thank in advance I have attached some picture to help understanding what I meant.

 

[ScottinAZ]

ok, from the looks of things, your front bushing only has marks on the outside edge, and that is NOT a sealing surface. I would dress them down to get rid of any raised edges and be very careful when putting the o-ring into its groove (if the groove is good, and the edges around it are good, you should be good, as long as you dont cut the o-ring installing it). As for the full cylinders, from what I understand (also having an MC-1 outdrive) you can "upgrade" to the later style cylinders from an Alpha, but you need to do it in pairs, and also with the hoses (they use external return lines, as opposed to our internal returns)

Dont know if you are running in fresh or salt water, but beware if you have damaged anodizing in the interior bore (where it was stuck to the piston rod), that the problem is likely to recur at some point in the future. Also for the record, my repair kit included the steel pressure cylinder, but did NOT include the endcap/guide such that you had stuck. If/when you take the piston apart, WATCH OUT FOR SMALL PARTS... there are 5 tiny springs and even smaller check balls in it that WILL go flying into another dimension if you lose control of them.... trust me, I found that out the hard way

 

[savery]

Also other question, I have a compartment for gear lube on my engine and the hose exit the boat via the transom and I need to connect it. I am not sure where I need to connect it. I have an idea but I'm not 100% sure if you could help me with that.

The gear lube hose goes to the hole behind the screw where you pointed, which is normally the vent. Take the plug out and install. There's a bracket bolted to the top two studs on the left side of the drive; that's supposed to support the hose, but it looks like yours is broken.

When you fill your drive with gear oil, start with the hose unhooked and the vent open, and then fill it from the bottom with a gear oil pump as normal until oil starts coming out the vent. Stop filling, attach the hose (make sure you have a new gasket installed), and then continue pumping more oil until you start to get oil in the reservoir on the boat. Then, remove your filler pump from the bottom, install the plug, and top off the reservoir to the full line inside the boat.

 

[dubs283]

The ram piston looks to me to be unusable, however I've never rebuilt a trim ram. Too much trouble, time and cost of parts to make it worth my while. You may be able to still find aftermarket rams that match your current ones, maybe...

If you decide to upgrade to newer style, eternal hose rams you will need a newer style pump assy as well. The newer style rams are not locked internally like the old style and will "float up" in reverse and you will be stuck with the trim full down/in underway as the old style pump is not "valved" for lack of a better term to maintain trim angle. This upgrade can be done fairly easily with excellent, reliable results

I would ditch the original style gear lube monitor system you have, never seen one perform well or look decent for that matter. Pressure test the drive, ensure it's sealed and run it like a regular MC-1 drive with a plug in the upper vent

 

[s_explore]

ok, from the looks of things, your front bushing only has marks on the outside edge, and that is NOT a sealing surface.

Ok thanks, that is also what I tought I will reuse it since no one seems to be selling this part.

As for the full cylinders, from what I understand (also having an MC-1 outdrive) you can "upgrade" to the later style cylinders from an Alpha, but you need to do it in pairs, and also with the hoses (they use external return lines, as opposed to our internal returns)

Yeah I was thinking maybe go with the alpha cylinder but they are quite expensive. If I am going to go that way I would probably replace the drive completely.

Dont know if you are running in fresh or salt water, but beware if you have damaged anodizing in the interior bore (where it was stuck to the piston rod), that the problem is likely to recur at some point in the future.

I am not sure which part are you talking about. Do you have a picture? I don't remember seeing an anode on the trim cylinder.

Also for the record, my repair kit included the steel pressure cylinder, but did NOT include the endcap/guide such that you had stuck.

Do you have a part number for the repair kit? I can't seem to find any manual with the MC1 or any part.

 

[s_explore]

The gear lube hose goes to the hole behind the screw where you pointed, which is normally the vent. Take the plug out and install. There's a bracket bolted to the top two studs on the left side of the drive; that's supposed to support the hose, but it looks like yours is broken.

When you fill your drive with gear oil, start with the hose unhooked and the vent open, and then fill it from the bottom with a gear oil pump as normal until oil starts coming out the vent. Stop filling, attach the hose (make sure you have a new gasket installed), and then continue pumping more oil until you start to get oil in the reservoir on the boat. Then, remove your filler pump from the bottom, install the plug, and top off the reservoir to the full line inside the boat.

Thanks a lot for the the explanation. This is what I thought but I wanted another person to confirm.

 

[ScottinAZ]

Ok thanks, that is also what I tought I will reuse it since no one seems to be selling this part.


Yeah I was thinking maybe go with the alpha cylinder but they are quite expensive. If I am going to go that way I would probably replace the drive completely.


I am not sure which part are you talking about. Do you have a picture? I don't remember seeing an anode on the trim cylinder.


Do you have a part number for the repair kit? I can't seem to find any manual with the MC1 or any part.

repair kit part number from Mercruiser (may be superseded, but all I did was a google search on the part number and got the equivalent) is 25-60342A-2. I got a pair of NOS ones on Ebay for a fair price

What I was getting at for the corrosion, is where the piece was stuck to the piston, may recur over time. the anodizing is likely damaged, and will allow the water to re-corrode the surface over time. Yes, there is a wiper seal, but they are NOT foolproof. AFAIK, these cylinders do not have a provision for an anode. the newer style rams with a different style of cap have provisions on the cap for an anode to screw onto them