Re: 1967 Evinrude 33 HP - impeller replacement help.
After reading the description the manual gave, I can see how it would be a bit tricky to visualize.<br /><br />But, since having recently dug into my own lower unit, I can make sense of it.<br /><br />The pinion gear is a smaller longer gear, fixed to the bottom of the driveshaft, and goes in vertically. When the motor runs, this gear is in constant clockwise motion.<br /><br />The bevel gears, are actually the 2 larger gears that occupy the lower unit foot itself, and are free to rotate on the propeller shaft. They are the forward and reverse gear, and are oriented perpendicularly to the pinion gear.<br /><br />The 2 large forward and reverse gears, have the pinion gear come down between them. These bevels on the gears, are where the ears from the clutch dog engage the gear.<br /><br />The clutch dog itself, has two protrusion on each outer edge (4 total). The clutch dog itself, is a splined piece that fits over the small splined section of the propeller shaft. The clutch dog itself, is moved by an articulating collar that pivots on a Phillips head screw on the side of the foot.<br /><br />When shifting, that clutch dog is slid frontward or backward along the splined portion of the driveshaft for F or R resepctively.<br /><br />So, the "bevel gears", I imagine, are what are being referred to as the actual forward and reverse gears in the lower unit...and are describing the physical feature as to how they engage w/ the clutch dog.<br /><br />Try to envision it like this...you have your pinion gear always rotating as it's fixed to the bottom of the driveshaft...The beveled forward and reverse gears are also consequently spinning at the same time as the driveshaft (but they go in opposite directions, one for F, one for R)...The F and R gears are free to spin on their bearing sleeve, so they both can spin at the same time...It's the actual clutch dog that slides on its splines (thus being fixed from free rotation as well) that permits the mechanical connection of forces...consider it a moveable link, so when you select the F gear for instance, and want power from it (remember, it's already rotating), you slide the clutch dog to that side of the prop shaft, the clutch dog ears engage w/ the bevels cut into the gear to recieve them, and now your previously freely rotating F gear, is now temporarily locked/engaged w/ the clutch dog (which is atached to the splines on the prop shaft and thus rotates)...then move to N, you disengage the clutch dog, so now there are no ears engaged.<br /><br />On my '64 40 HP, the pinion gear itself, went up into the rest of the lower unit and bearings several inches...so even w/ the driveshaft removed, things below were still staying where they should.<br /><br />When it comes time for actually reinstalling the impeller, there are plenty of ways to do it, some easier than others.<br /><br />The impellers on these motors are small, and easily set into place. I succeeded by rotating the driveshaft clockwise (and getting in my head how the vanes of the impeller would be bent when doing so)...for my situation, it was easy enough to just use a combination of twisting, and/or just bending and placing the impeller up in the water pump housing. Then when that was done, use sealant on the appropriate mating surfaces, and slide it down over the key. Its the sort of thing that seemed a mystery till you do it the first time, then it becomes relatively easier...sorry the disassembly has been less than fun.<br /><br />So long as you are waiting for parts, and if there is a trace of material to grab on to, you might be well served by trying to get some penetrating oil in what remains, soak and tap...I was often skeptical that it'd do much, but I've had my share of surprises/relief, where I actually felt it helped.<br /><br />If it comes to drilling and tapping...start w/ as flush ground a bolt surface as you can get, and use a center punch and good sharp bit to start...if a Dremel tool is at your disposal, using a burr to ensure you are grinding as close to the center as possible, will be an asset. And true, since it's a small bolt, having a hardened steel easy out screw extractor break in there would be a nightmare indeed to remove, itll be your call.<br /><br />I encountered the same pleasures when pulling apart my motor after decades of being together (and the previous owners not using some anti-seize on the threads)...had to tap two holes...and a bit of patience and things worked out. Best of luck.
.<br /><br />Thx.