Rebuilding Gear Case of 48SPL-Part 3

[Oldslowandugly]

I finished de-greasing the parts I removed from the corroded gear case [from a 48-SPL outboard engine].

Tthe propeller bearing carrier had to cut out of the case, and the bearing carrier was severely corroded on the flange surfaces. There was a coating of black crud hiding the corrosion.

After de-greasing [the propeller bearing carrier] I scoured off the corrosion using a stainless wire brush on an angle grinder. The reason the bearing carrier was stuck in place so badly was the corrosion.

The [corrosion of the propeller bearing carrier] was due to the prior owner not [failing to]tilt the engine out of the [salt]water. The boat sat at the dock with the gear case submerged in saltwater for untold seasons.

[jimh]

If choosing a gear case as a project for rebuilding, to make the project easier perhaps it would be worth some time and perhaps some added expense to select a gear case for rebuilding that was not chronically submerged in saltwater during its entire lifetime of use.

Why pick the worst possible candidate for a rebuild?

Considering the total number of 48SPL engine manufactured, there must be plenty of old engines that can be bought as parts that do not have a gear case with extensive corrosion due to continual immersion in saltwater. Choosing a gear case for rebuilding that has been immersed in saltwater for untold hours seems like a bit of a bad way to start the project.

[Oldslowandugly]

Some history: The problem child was the gearcase that came with the 1993 motor. It worked well for the 20 years I ran it on two different boats. It was the entrance of water into the lower unit oil that prompted me to get the seals fixed. That went downhill immediately as the dealership gave up on trying to get it apart in the usual way. I salvaged the season by swapping my old 30hp Evinrude in place of the 48SPL. During that season I did source a freshwater used gearcase from an online auction. The only problems were the rusted bearings still inside and cracked cavitation plate. I also found a fresh water used 48SPL motor in Baltimore that I hoped I could just use it's gearcase as is. That was not to be as it also had some water in the gearcase. But it was in much better condition than the parts gearcase so I decided to re-build it and post my efforts here.There were no major parts replaced and that one is finished. That leaves me to re-build the parts gearcase with the parts salvaged from the problem child unit. I will continue with that and post for the benefit of anyone faced with building a lower unit from scratch with an empty gearcase. Let me assure you that many parts are obsolete and hard to find. Even clean used parts are hard to come by and commanding a high price. An entire lower unit or parts motor are almost impossible to find, cost a fortune, and are usually located far away requiring expensive shipping. I was ready to just get a brand new ETEC motor but production ceased at the worst time for me.

[Oldslowandugly]

The empty parts gearcase was de-greased and all threads chased with a hand tap.

Use a tap to chase all threads.

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The cracked anti-ventilation plate was repaired by a welding shop.

Cracked anti-ventilation plate requires welding.

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Anti-ventilation plate after TIG welding.

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Because the upper driveshaft bearing carrier had to be replaced with a new one taking a measurement from the pinion gear to the carrier mounting flange was required. There is an expensive tool kit to do that. I was able to locate the exact measuring tool part for a 40-48-50 hp motor on the internet at a cheap price.

The pinion gear must be installed onto the driveshaft and the nut tightened to a torque of 45-foot-lbs. The thrust bearing is installed next, with two thrust washers, and the upper bearing carrier onto the driveshaft. Tape the splines so they don't cut your new seals.

I also found the OMC collar that the carrier sits on for measuring on the OMC tool. You could get by with just letting the carrier sit on a vice with the driveshaft hanging between the jaws. I used the vice to hold the OMC collar. Measure from the flat edge of the pinion gear to the flange of the carrier. The measuring tool is exactly 7.002-inches long. You could use a length of bar stock exactly 7.002" long for a measuring tool. The clearance gap must be 0.030-inches. Any more than that requires thrust washer shims to bring it to specs. The original shims were destroyed when taking the unit apart. They measured at 0.006 and 0.007-inches together making the required shim pack 0.013-inches. When I installed the measuring tool the gap was exactly .030-inches, and no shims were required.

On the other fresh water gearcase no parts were replaced so I was able to use all the original bearings, washers, and shims. When building from scratch with non-original parts it is imperative to measure everything.

[Oldslowandugly]

The assembled parts are measured with 7.002-inches-long gauge. The gap must be 0.030-inches. The OEM shims totaled 0.013-inches. The new parts measured exactly 0.030-inches and required no shims.

[Oldslowandugly]

The new bearings are placed into the gearcase. I have the correct OMC tools for this, but there is a workaround. First I assembled the pinion bearing tool and placed the pinion bearing onto the driver end. Use some OMC needle bearing grease to hold it in place.

Pinion bearing tool assembled with new bearing in position.

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I dripped some gearcase lube into the cavity to ease the installation. The tool is used to drive the bearing down into the cavity and places it at the correct height.

Tool sets the pinion depth using the spacer and plate.

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If you had prior measured the top of the old pinion bearing to the top of the gearcase you could use a length of the proper sized pipe to drive the new bearing in to the same height. After driving the new bearing with the correct tool I then measured the installed height. It was 6 and 5/8-inches. Now you can install the bearing at the correct height without having the measuring tool.

Take the pinion bearing retaining screw and screw it into the side of the gearcase. Use LokTite on the threads, a new O-ring on the shaft, and a bit of sealer on the threads near the O-ring. Torque to 40 to 80-inch-lbs.

6 and 5/8" from top of pinion bearing to top of gearcase.

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If you accidentally drive the bearing in too far, you can drive it down and out all the way. The factory service manual says to use a new one if the bearing is removed for any reason. That recommendation is due to driving out an old bearing usually ends up damaging the bearing. The bearing I removed from my corroded gearcase was as good as the new one maybe because I oiled it up diligently. I saved it for a spare. A well-oiled new bearing should come out and be good for at least one do-over--if the bearing was not forced ino place. The rusty bearing I removed was badly damaged due to the force required to extract it.

[Oldslowandugly]

The last bearings to go in are the propeller shaft bearings at the very front of the gearcase. There are two bearings, one short, and one tall. Both are the same diameter. I have the OMC installer tool but you could easily use a length of the proper sized pipe to do this. The install tool gets assembled and the short bearing goes on first. The flat side with writing on the bearing faces up. Use OMC needle bearing grease to hold it in place.

OMC bearing tool with short bearing.

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I squirted some gearcase lube inside to ease assembly. Place the gearcase on the floor open end facing up at you. Insert the short bearing on the tool or use a magnet-on-a-stick to get it down in place. The tool plate locates the driving handle so the bearing goes in straight. If using a pipe be sure it does go in straight. The handle gets hit carefully with a hammer. It will go in easily so if not don't just bang harder. See what is wrong. The bearing will bottom out and then the hammer will make a hollow sound indicating the bearing is at the stop. Then the tall bearing goes in. On the OMC tool the driver gets reversed and the tall bearing goes on the driver. Retain with the needle bearing grease. The flat side with writing faces up. It gets driven in the same way. It butts up against the short bearing and the hammer blows will sound hollow when it is at the stop. That is all of the gearcase bearings that get installed into the gearcase itself.

Both bearings installed back-to-back.

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[Oldslowandugly]

We had a few days of nice weather so I painted the finished gearcase. I fill the defects with Epoxy and fair it by hand. Then I use at least three coats of Interlux Primocon underwater metals primer. This primer is suitable for prolonged usage below the waterline. I find it extremely durable on aluminum parts.

First coat of Primocon underwater metals primer.

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I am at the point in re-assembly of the parts gearcase that I must decide which type of seals to use on the propshaft bearing carrier. I failed at properly installing the single case extended lip seal that is now recommended for the propshaft. I found out that there is a special installation tool that is used on these type seals. It has an indented cavity that protects the extended lip. It goes for $100 and I am reluctant to spend that on a one-time-use tool. I am wondering if I can substitute something else but so far no luck. I may just use the two single lipped seals as I used on the other gearcase.

[jimh]

What would be the expected normal cost for the TIG welding you had done on the broken anti-ventilation, exclusive on any special friend-only pricing?

[Oldslowandugly]

The repair was done for no charge; the welder owed me a big favor. I gifted him a 5-lbs sleeve of 4043 alloy TIG rods I had no use for.

This repair required much skill and experience. I watched through a welding helmet as he worked. The large mass of the aluminum gearcase was such a heat sink that he had to spend many seconds getting a molten puddle, then quickly jump the arc over to the broken part, then back to the case, to keep both sides molten. All the while feeding the 4043 rod into the puddle. It was fascinating to observe.

[dtmackey]

Tig welding is an artform, and with thicker metal like a gearcase (with a large mass), preheating is key for a good weld. That's why many places that weld outboard gear cases units ask for the gear case to be stripped. They preheat the entire gear case to prepare for welding.

I purchased a Tig AC/DC welder, used it three times, and recently sold it because I knew I didn't have the time to learn that process and most of my welding can be done with a spool gun attachment on a Mig.

If I do need something Tig welded, I visit a friend with the equipment.

D-

[Oldslowandugly]

Tig is an artform and with thicker metal like a gearcase (large mass), preheating is key for a good weld...

We were working in a cold shop on a very cold day. The gearcase sucked heat like you wouldn't believe.

My skillful buddy used to do welding at an aerospace company when he was young. He let his helper try and the helper made a weld as ugly as I would have. My buddy re-melted the ugly weld and just continued along. I love watching people work who know what they are doing.

[jimh]

Getting that corroded old saltwater gear case repaired by a high-skill aerospace-qualified welder sounds like it would cost more than the gear case was worth.

[dtmackey]

Tig is an artform and with thicker metal like a gearcase (large mass), preheating is key for a good weld...

We were working in a cold shop on a very cold day. The gearcase sucked heat like you wouldn't believe.

My skillful buddy used to do welding at an aerospace company when he was young. He let his helper try and the helper made a weld as ugly as I would have. My buddy re-melted the ugly weld and just continued along. I love watching people work who know what they are doing.

I agree, watching someone who is good is enjoyment. I've brought things to a friends shop and he's nuclear certified for welding on power plant pipes and other things. Looking at his welds is amazing and like a perfect stack of dimes. I've never see anything as perfect as his stuff. Me, on the otherhand, not so good at it.

D-

[Oldslowandugly]

Getting that corroded old saltwater gear case repaired by a high-skill aerospace-qualified welder sounds like it would cost more than the gear case was worth.

Well the corroded case is just that: junk. Unfortunately this partiular gearcase was the only one available in good condition and at a fair price.

The amount of misrepresented overpriced junk out there is staggering. I am not even sure what year it is but the upper driveshaft bearing carrier is the three-bolt-hole style. That makes it the one I needed.

Even though the friend is highly skilled, he now runs a small iron works company making railings, awnings, and gates. He is a diamond in the rough.

Any real automotive store that has a machinist on duty can do that type of welding. Several years ago I had a 1995 Chevrolet LT1 aluminum timing cover repaired at such a shop. It had a broken off grade 8 bolt and a five inch crack. The cost was very reasonable.

The current market price of a complete 40-48-50-HP 20-inch gearcase is $2,980--if you can find one. The empty case itself new is totally unavailable. I just did a search and the only used correct case available is going for $770 and $56 shipping, plus tax.

In this instance repairing what I have makes a lot of sense.

[jimh]

Thanks for the comments, but I still don't have any idea what a good welder would charge. The last time I hired a welder was in c.1980. He was not a craftsman. He just did some marginal quality arc-welding on steel on a rough structure. His fee seemed quite reasonable at that time, maybe $50 for eight welds. And he came on-site to do the work. But that was 40-years-ago. Back when you could buy a used Boston Whaler 13-footer with a trailer and an engine that ran very well for $1,000. The notion that a replacement gear case for a 40-year-old outboard is going to cost $3,000 is just nuts.

[Oldslowandugly]

I absolutely agree. When Bombardier assumed OMC they pledged to maintain the repair parts supply just as OMC had. Obviously that has not happened. If you search the big outboard motor parts suppliers you will see very many parts discontinued and unavailable. Now with the demise of both Johnson and Evinrude I expect the situation to only get worse.

[Oldslowandugly]

Now that the bearings are in I began assembling the other parts onto the gearcase. First in goes the forward gear thrust washer. The roller thrust bearing gets glued on to the forward gear with the OMC Needle Bearing grease. Use a magnet-on-a-stick to gently guide the gear in so it does not drop in hard.

Hold forward gear with a magnet and lower into place.

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The FSM says to assemble the driveshaft parts and add sealer to the upper bearing carrier. Then insert the shaft and the pinion gear. I found that unwieldy. The pinion can only go on from the bottom. Leave the carrier off for now. You will need to grab the driveshaft and raise it enough so that the pinion gear can clear the shaft and fit into the forward gear. If the driveshaft sticks down too far into the case the pinion will not get past it.

Driveshaft too deep will block pinion gear.

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I found the best way was to hold the pinion gear with the magnet and raise the driveshaft up until the pinion cleared it and slid into position. There is a cavity at the top of the case where the shaft comes out. If you raise the shaft and insert the pinion into the cavity, then the pinion will clear the forward gear and you can lower the shaft right into the pinion gear.

Hold pinion with magnet and lower driveshaft into it.

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[Oldslowandugly]

Next add the pinion nut. I used a short 11/16" socket and breaker bar to hold the nut. I packed the socket cavity with paper towel so the nut sat right at the top of the socket. Hold the breaker bar and turn the driveshaft to screw the nut on. A driveshaft socket is used or else a one-size-fits-all socket just fits the driveshaft splines. Torque to 40-45 foot pounds.

11/16" socket on breaker bar holds the pinion nut.

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Now you can install the upper driveshaft bearing carrier. I used Ultra Black on the gearcase flange surfaces. Anti-seize in the bolt holes. Tape the driveshaft splines so as not to cut the new seals. Lightly grease the driveshaft with Triple Guard grease. Slide the carrier down onto the case and bolt into place. Torque bolts to 14-16 foot pounds. Then we install the shifter rod and pivot. Slide the shifter cover assembly onto the shift rod. Keep it up and out of your way for now. Screw the shifter rod into the shifter pivot. Move the shifter dog into forward gear. The shifter cradle is put onto the end of the shifter dog shaft and is held in place with the OMC Needle bearing grease. Again, this is what you are doing.

Shifter pivot engaged on cradle.

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Use a flashlight and look at what you are doing. This time I realized there is a ledge cast into the shifter rod cavity just above where the propshaft enters. If you install the propshaft so the cradle just totally enters the cavity, then as the shifter rod/pivot is slid down in, the ledge guides the pivot arms right into the slots on the cradle. Kudos to the engineer that designed that casting. Once you are sure the pivot is engaged with the cradle then insert the pivot retainer screw through the side of the gearcase. I found a big nail with a sharp point ground on the end was perfect for sticking into the screw hole and maneuvering the pivot hole into position so the screw will go through it. Use a new O-ring and a bit of sealer on the screw shaft. Torque the screw to 48-80 inch pounds. Now slide the rod cover down the shaft. Triple Guard grease is used on a new outer and inner O-ring. The rod bushing threads are sealed with Adhesive M or 3M 847. Torque to 48-60 inch pounds. The cover bolts are torqued to 60-84 inch pounds. Here is the top end all assembled.

Bearing carrier and shift rod cover in place.

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[Oldslowandugly]

Now I have to repair the propshaft bearing carrier that was salvaged from the bad gearcase. While trying to extract the carrier I broke off a long bolt that was used with the steering wheel puller. Drilling out a steel screw that is in aluminum is always a challenge. I drilled straight through and out the end of the blind hole. That ruined most of the original threads. I then re-tapped the original 1/4-20 hole for the next larger size 5/16-18 bolt. I found the only type bolt head that would fit without hitting the anode was a narrow flange head style. I had one such bolt but it was too long and had to be cut shorter. Thread a die up the shaft so that after cutting it will chase the threads on the way off. I cut the bolt down with a hacksaw.

Cutting bolt with die in place to clean up threads.

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I used an old anode for a fitting test and it had to be drilled out for the bigger bolt too. The shortened bolt fits just fine. I filled the end of the blind hole from behind with epoxy to restore the blind end and keep saltwater out.

Small head oversize bolt just clears the anode.

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Then I took a new anode and drilled one mounting hole for the oversize bolt. I will save it for when this gearcase gets put into service.

[Oldslowandugly]

Timing is everything. I just purchased a used extended lip seal installation tool off the web. When it comes I will try again to install the new updated type seal into the propshaft bearing carrier. The tool is used not only for the propshaft seal but also the upper driveshaft bearing carrier extended lip seal. The new upper bearing carrier I purchased came with the new type seal installed. The parts kits now include the new type seals for both applications.

[Oldslowandugly]

Here is what I found about the new type seals. This also says to use the DPL lubricant and not sealer on the seal. It may be that not having the proper tool is what ruined my attempt to install the new seal. But looking at the cross section picture, the pipe I used should not have damaged anything. I will still use my own sealer so there is no chance of leakage. I have one of the new seals left and I will install it when the tool arrives.

Instructions for new type seals.

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[Oldslowandugly]

This is how the old style back-to-back seals get installed. The cases are steel and fit tightly against the carrier. Sealer makes sure nothing leaks. Much easier.

Old style back-to-back seals.

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[Oldslowandugly]

A nice day so I went outside to install the re-built 1996 lower unit onto the 1993 48SPL. After chasing all the threads I brushed some anti-seize into the bolt holes. I made sure the shifter dog in the gearcase was in neutral. The upper shifter detent on the powerhead must also be in neutral. Wipe some moly grease on the driveshaft splines but not on the top end. I fitted the lower unit onto the mid-section and screwed the big end bolt in to secure it. Then I screwed one of the four front bolts in so that the unit was tight against the mid-section. Here I encountered another problem. The top of the shifter rod did not fit correctly into the clevis that is part of the shifter detent on the powerhead. I had carefully measured the turns of the shifter rods on both lower units and they both were at 10 turns. For some reason the difference in manufacturing tolerances were such that the recorded shifter rod height was not correct. What I had to do was lower the rod by screwing it in one whole turn at a time because the top of the rod must point forward. Each time I made an adjustment I had to unbolt and remove the lower unit just to screw the rod in one turn then replace it and test again. It took a total of three turns for the hole in the shifter rod to meet the hole in the clevis perfectly. Then the clevis bolt can be inserted and tightened. Oddly the FSM shows no torque value for that bolt. The final height of the shifter rod is not really important. What is important is that the shifter dog in the gearcase MUST be in neutral. Verify by spinning the propeller. The shifter detent on the powerhead MUST be in neutral. At that point if the clevis bolt fits perfectly into the clevis and the shifter rod- you are good to go. Then you can install the rest of the bolts. Torque the four 3/8" bolts to 18-20 ft lbs and the rear 7/16"bolt to 28-30 ft lbs. My shift cables are not in place yet. If your cables were in place and the detent was not in neutral then you can adjust it. There are two bolts on the detent that loosen and allow it to be adjusted for neutral. Next comes a running motor test in a barrel of water.

[Oldslowandugly]

Here is the new type seal going in to the propshaft bearing carrier. I used a section of thin walled sink pipe last time. This time I have the proper tool so I will use it. The tool edge locates the seal and makes sure it is square in the bore. The difference is that I will use Ultra Black sealer instead of the DPL penetrating oil to be positive it doesn't leak around the edges like last time. Make sure the exposed lip faces towards you and the covered lip faces into the gearcase. The picture shows the correct position on the bigger seal [propshaft] and the incorrect position on the smaller seal [driveshaft]. The seal will fit the tool both ways so be sure it is correct. This tool works for both applications. Once in place fill the cavity between the seal lips with Triple Guard grease. Then I screwed two of the long bolts into the carrier for control. I wiped Ultra Black all over the O-ring and the carrier flange and inserted it into the gearcase. I again needed to use the big woodworking clamp and a section of PVC pipe to drive the carrier in the last inch. Once seated I installed the retainer clamps and bolts. After the sealer cures I will pressure and vacuum test.

[Oldslowandugly]

I found this woodworking clamp tool indispensable to press the carrier in the last inch. There is a ledge inside that the O-ring must ride up on and compress. Sealer makes it even harder to do. I prefer this method to swinging a big hammer at the bearing carrier. Now the gearcase rebuild is complete. This parts case is the one I bought online and filled with the parts I salvaged from the corroded case. I repaired the missing chunks from the skeg with Marine Tex. After buying some special tools, some new bearings, and two re-seal kits, the cost was very reasonable. Even if you can find a complete used parts gearcase it is very expensive and may need re-sealing anyway.

[Oldslowandugly]

I tested the rebuilt 1996 fresh water gearcase in a barrel of soapy water. The 48 hp motor has not been run in two years but it started right up. I let it get to operating temperature before shifting into gear. It went into forward- neutral- reverse with no drama or expensive sounds. Now I will let it drain all the water from the powerhead before I try to drain the gearcase oil. If it is free of water then I can re-fill with clean fresh oil and be done. -

[Oldslowandugly]

The parts gearcase filled with salvaged parts passed the pressure and vacuum tests. I violated the old hot-rodding adage about never changing more than one thing at a time. Then you won't know what worked. I used sealer on the new style seals and I used the correct installation tool. I'd put my money on the sealer. Now that both gearcases have passed the tests I am happy that I have two complete running 48SPL motors with tight lower units. The cost of the special tools was spread between two jobs and if I ever need to do this again I have the tools and the talent.

[dtmackey]

Oldslowandugly - here is a real quick way to do prop seals. A dealer will pull the bearing carrier, requiring special tools and charge a bunch of labor. Prob several hours if he's pulling the lower off the boat. The trick I use is to put 3 drywall screws into the seals (say away from the shaft). Once they are in, get a pair of wire cutters and grab the screw and slowly rock along the bottom and work on each side and the seal pops right out. Total time is about 5 mins. Next for driving new seals in, use a PVC pipe and if it does not match the seal face, grind a washer so that it pushes the deal in without damage. Seal install is under 2 mins, So now you can get this done in 10 mins or less with no special tools.









Quick and easy way that anyone can do prop seals.

D-

[Oldslowandugly]

Yes, I know of that trick. But it is only good if the prop shaft seal is the culprit. And if the shaft is not grooved. I wonder if that technique will work on the new style single case double lipped seals? They don't have the same steel case to screw into. The last two times I tested underwater in my slop sink only one was just the prop shaft seal. The other was all three seals. Just my good luck that one was the frozen up unit. Maybe it is just me but when I am dealing with an original part I tend to take it all apart just to see what else is going on because it is old. EDIT: the rebuilt gearcase was drained of the used oil and a small amount of debris came out with it. That is good so now I know the case is clean so I refilled with fresh Hi-Vis oil.