Reduction Gear Removal

[AustinPowered]

Sadly I have determined the engine in my boat needs to be replaced. I have found a used late model engine which has a reduction gear. My early model engine does not have a reduction gear.

Will I be able to use this engine? What is involved in getting the reduction gear removed?

Thanks,

[hanleyclifford]

It is not a difficult procedure to remove the reduction gear. You will need to use some parts from your old transmission. The drive coupler from your old engine will have to be removed without damaging it - good idea to use a puller. The reduction gear unit comes off easily with six bolts; then the adapter. If you are not familiar with these things and plan to do the work yourself I urge you to obtain a copy of the Moyer Marine Overhaul and Service Manual. If the reduction unit is servicable or can be repaired I would be interested in buying it. Don't hesitate to ask for help as you proceed.

[msmith10]

Hanley,
I also have a spare reduction gear that I got when I bought a spare reversing gear (I love to have backups). It looks to be in good shape and if you ever need it, let me know. I don't need the reduction gear, just the reversing gear.

[AustinPowered]

I have Don Moyer's "Service and Overhaul Manual, 1st Edition." During my cursory inspection of this I did not find any information on the reversing gear.

Do you know if the 1st Edition is the latest or has it been updated?

Or most likely, did I not look in the right place?

Thanks,

[hanleyclifford]

The reversing gear is discussed in chapter 6. However, no information on the 2:1 reduction unit is covered. If you go to the online catalogue and find product OREV 25-343, you can get an idea of what sort of job you are facing. If you switch out the unit with reversing gear it will not be necessary to change the tailshaft - the direct drive is a different tailshaft. If you have not worked inside the A4 transmission before, this could be a daunting undertaking. You will be taking two engines apart (partially). How are your mechanical skills?

[hanleyclifford]

On second thought, why not consider using the 2:1 reduction set up? It only requires about an additional inch of height. But you will have to have the driveshaft shortened and of course get a new prop. All told, this option may be more user friendly and will give a better performance result.

[Marian Claire]

Austinpowered: Feel like a vulture here but early models don’t show up that often. I would be interested in any parts, HC has dibs on the 2:1, but I could use a starter, distributor etc. Where are you located? Good luck with the changeover. Dan S/V Marian Claire

[AustinPowered]

Success! Sort of. The new engine is in my garage and the reduction gear has been removed. The old engine is sitting in the main cabin of my boat and the drive coupling and rear main seal have been removed.

Upon attempting the switch I have discovered the tail shaft is different. No problem, I'll just swap them out from old to new.

Any thoughts on the simplest way to do this? Will I need to remove the gear housing and get the reversing gear out to accomplish this?

I have Moyer's manual and it looks like the shaft is held in by the adjusting collar. It also looks like whatever I need to do would be easier to do with the gear assembly out of the case. Maybe just swap the entire assembly?

Do I need to remove the accessory drive and or the distributor to remove the case?

Thanks,

[hanleyclifford]

If you go to the on line catalog on this site and look under overhaul/reversing gear you can see a picture of how Moyer Marine sells the 2:1 reduction unit. The explanation is what you are looking for.