I have a 1988 mercruiser 4.3 with an alpha 1, I need help with removing the lower gear unit, so I can replace the impeller, I have all the bolts out, but it dont drop down, I dont want to beat on it, am I missing something?
There are a couple that are easy to miss. There is one under the zinc - and don't forget the one up front by the shift shaft.
If you really do have all the nuts and bolts out, then it might just be corroded on. There are some tips and tricks to try... but make sure you have all the fasteners off.
I took 5 nuts off, under the zinc? the corrosion devise? it looks like there is a hole right above that where there may have been a bolt, but it wasnt in there, it appears as though the zinc is held in place by the 2 rubber fins
Success!!! I had went out there and started looking at how zinc was mounted, it was a 3/8 allen then there was another allen bolt, I got it finally, thank you for your help, and keep your eye open for me, Ill probably be back
Since you did accedentally find out how to get the drive apart, here is a link to the OEM service manual. You need to look at it for putting it back together, and don't forget the quad ring between the upper and lower.
and don't forget to turn the driveshaft clockwise when your pushing that housing down... if you get it backwords and run the engine you'll be doing the job again and buying a new pump.
While it is a good idea to turn the shaft the proper way, on an any of the short vaned pumps (like the Alpha ones, on down to the one drives) the vanes of new impellers will flip around to the proper direction. Which won't happen with the Alpha I Gen II drives with the long vanes, those will not flip over and can cause an overheat.
