Smartykrs1
08-09-2023, 02:16 PM
1999 90HP ELPTO Oil injected 2-stroke (S/N: OG775503)
Went out for a spin on Lake Texoma a couple weeks ago. On the way back in, the old fishing skiff suddenly lost about 30% of speed and it sounded like I heard some clanking coming from the outboard and knew it wasn't the engine. Finally got around to draining the lower unit a couple days ago and found nice, dark oil with no water present. What was present, however, was a bunch of metal chips and chunks. These are not the sand/dust sized flakes you might see under normal conditions but were chunks that had clearly broken off something and were now stuck to the magnet on the oil cap screw.
After draining all the gear oil, I began the disassembly procedure according to the service manual. Got into the gear case and removed the prop shaft, bearing carrier, clutch dog and reverse gear; all of which looked fine. When I shined my flashlight into the gear case, I found the problem. One of the teeth had broken off the forward gear.
522382
Replacing any or all the gears requires the gear case be re-shimmed. Once you have the new gears ready to install, you install the forward gear and bearing, followed by the pinion gear. Shimming the pinion gear to set pinion depth is the next step and the service manual calls for a Pinion Gear Locating Tool (91-12349a2) to be used to set pinion depth. Once you've installed the Bearing Preload Tool (91-14311a2) to tension the mechanism, you shim the pinion gear using the Pinion Gear Locating Tool and some long feeler gauges to set the pinion gear at 0.025" above the gauging block. 91-12349a2 is designed to handle different sizes of gears and has many combinations. The service manual calls for using locating disc 3 and gauging block surface 8 when setting 2.31 gears in the 3.0L gear case.
Now for the problem. Pinion Gear Locating Tool 91-12349a2 costs about $900, making the cost of this tool a little less than twice what a pro would charge to perform the entire rebuild.
There is a non adjustable Pinion Gear Locating Tool made for use in the 3.0L gear case: 91-56048 for 1.62:1 and 1.75:1 gears.
Can this tool be made to set the pinion depth on 2.31 gears? Is the pinion gauging block on 91-56048 higher or lower than gauging block surface 8 of the 91-12349a2 (adjustable) as viewed installed inside a gear case? Can some material be removed from the gauging surface to achieve my objective? Or the specified pinion depth measured from the center bore of the gear case with 2.31 gears?
Alternatively, could I use Pinion Gear Locating Tool 91-74776 for 1.87:1 and 2.0:1 gears and 2.5L gear cases plus or minus some distance off the gauging surface?
Any help is greatly appreciated. Alternatively, if someone has a used 91-12349a2 they'd like to sell me, please send me a DM.
Some of this was covered in Mercury Tech:pinion gear shimming tool question (https://www.screamandfly.com/archive/index.php/t-173128.html)
Thanks all, John
Went out for a spin on Lake Texoma a couple weeks ago. On the way back in, the old fishing skiff suddenly lost about 30% of speed and it sounded like I heard some clanking coming from the outboard and knew it wasn't the engine. Finally got around to draining the lower unit a couple days ago and found nice, dark oil with no water present. What was present, however, was a bunch of metal chips and chunks. These are not the sand/dust sized flakes you might see under normal conditions but were chunks that had clearly broken off something and were now stuck to the magnet on the oil cap screw.
After draining all the gear oil, I began the disassembly procedure according to the service manual. Got into the gear case and removed the prop shaft, bearing carrier, clutch dog and reverse gear; all of which looked fine. When I shined my flashlight into the gear case, I found the problem. One of the teeth had broken off the forward gear.
522382
Replacing any or all the gears requires the gear case be re-shimmed. Once you have the new gears ready to install, you install the forward gear and bearing, followed by the pinion gear. Shimming the pinion gear to set pinion depth is the next step and the service manual calls for a Pinion Gear Locating Tool (91-12349a2) to be used to set pinion depth. Once you've installed the Bearing Preload Tool (91-14311a2) to tension the mechanism, you shim the pinion gear using the Pinion Gear Locating Tool and some long feeler gauges to set the pinion gear at 0.025" above the gauging block. 91-12349a2 is designed to handle different sizes of gears and has many combinations. The service manual calls for using locating disc 3 and gauging block surface 8 when setting 2.31 gears in the 3.0L gear case.
Now for the problem. Pinion Gear Locating Tool 91-12349a2 costs about $900, making the cost of this tool a little less than twice what a pro would charge to perform the entire rebuild.
There is a non adjustable Pinion Gear Locating Tool made for use in the 3.0L gear case: 91-56048 for 1.62:1 and 1.75:1 gears.
Can this tool be made to set the pinion depth on 2.31 gears? Is the pinion gauging block on 91-56048 higher or lower than gauging block surface 8 of the 91-12349a2 (adjustable) as viewed installed inside a gear case? Can some material be removed from the gauging surface to achieve my objective? Or the specified pinion depth measured from the center bore of the gear case with 2.31 gears?
Alternatively, could I use Pinion Gear Locating Tool 91-74776 for 1.87:1 and 2.0:1 gears and 2.5L gear cases plus or minus some distance off the gauging surface?
Any help is greatly appreciated. Alternatively, if someone has a used 91-12349a2 they'd like to sell me, please send me a DM.
Some of this was covered in Mercury Tech:pinion gear shimming tool question (https://www.screamandfly.com/archive/index.php/t-173128.html)
Thanks all, John