MHZ 1/5 Scale Outboard Drives

[Rezendes]

My son and I are building two MHZ 55? X-Cat catamarans. We are using MHZ?s 1/5 scale Outboard drives. We have disassembled them for polishing and powder coat painting. We also wanted to remove the gears to try and develop new gears with improved materials. However, try as we might we have been unable to remove the gears from their shafts. I have tried to contact MHZ directly through their website with no success. Has anyone in the OSE Firum successfully removed these gears? If so how?

Thank you in advance for any help you can offer.
Everett & Eric Rezendes

[fweasel]

Brian Cooper on one of the Facebook groups is developing an outboard for a 56mm motor that uses a flex cable, and not gears, which have always been the achilles heal of the scale piece.

FB_IMG_1694821457237.jpg
FB_IMG_1694821453747.jpg
FB_IMG_1694821466726.jpg

[Rich]

My son and I are building two MHZ 55? X-Cat catamarans. We are using MHZ?s 1/5 scale Outboard drives. We have disassembled them for polishing and powder coat painting. We also wanted to remove the gears to try and develop new gears with improved materials. However, try as we might we have been unable to remove the gears from their shafts. I have tried to contact MHZ directly through their website with no success. Has anyone in the OSE Firum successfully removed these gears? If so how?

Thank you in advance for any help you can offer.
Everett & Eric Rezendes

Rezendes, you can remove the gears from the shaft. You have to remove the grub screws and then slide the gear off. If the gears won't move heat them up slightly with a propane torch and they should slide off. Fweasel is right the gears are the problem with these outboards. I am also working on a different version that uses flex shafts to solve the durability issue. If you run these drives on a 20k rpm setup they should be fine as long as you keep up on the gear lube. FYI if you do get a little water in the lube its not a huge deal in my experience. I will say this, as you pass 20k rpm the gear lube will not be able to lubricate the gears and at the point they will self destruct.

Brian Cooper on one of the Facebook groups is developing an outboard for a 56mm motor that uses a flex cable, and not gears, which have always been the achilles heal of the scale piece.

[ATTACH=CONFIG]177893[/ATTACH]
[ATTACH=CONFIG]177894[/ATTACH]
[ATTACH=CONFIG]177895[/ATTACH]

I have to contact Brian I haven't heard back on if he tested them yet or not that was back in May.

[fweasel]

Rezendes, you can remove the gears from the shaft. You have to remove the grub screws and then slide the gear off. If the gears won't move heat them up slightly with a propane torch and they should slide off. Fweasel is right the gears are the problem with these outboards. I am also working on a different version that uses flex shafts to solve the durability issue. If you run these drives on a 20k rpm setup they should be fine as long as you keep up on the gear lube. FYI if you do get a little water in the lube its not a huge deal in my experience. I will say this, as you pass 20k rpm the gear lube will not be able to lubricate the gears and at the point they will self destruct.





I have to contact Brian I haven't heard back on if he tested them yet or not that was back in May.

He's been offshore a lot with work. I haven't heard or seen any new reports on them either.

[Rezendes]

MHZ 1/5Scale Outboard Drives

He's been offshore a lot with work. I haven't heard or seen any new reports on them either.

Thank you for your reply. I am aware of Brian Cooper?s efforts to find a better option to the MHZ Drives. He and I have been in contact for a couple of years. He has kept me up to date on his efforts. However, my son and I already had four of these drives and just finished painting the 55 inch MHZ X-Cat hulls and the outboard motor housings. We are aware of the problems others have had with the gear sets. We have disassembled the drives and are attempting to at least insure that the gears are properly set with the correct lash. To do that we have to remove the gears from their respective shafts and have not been successful so far. That?s why we are reaching out to the forum to see if anyone has successfully removed the gears and exactly how they did it. We have tried to tap them out using a metal punch; tried using a small rod chucked in our large drill press to push the gears off the shafts; tried heating the gear and now having them soaking in WD40.

[Rich]

He's been offshore a lot with work. I haven't heard or seen any new reports on them either.

I just got in touch with him today. Yep he is still busy.

Thank you for your reply. I am aware of Brian Cooper?s efforts to find a better option to the MHZ Drives. He and I have been in contact for a couple of years. He has kept me up to date on his efforts. However, my son and I already had four of these drives and just finished painting the 55 inch MHZ X-Cat hulls and the outboard motor housings. We are aware of the problems others have had with the gear sets. We have disassembled the drives and are attempting to at least insure that the gears are properly set with the correct lash. To do that we have to remove the gears from their respective shafts and have not been successful so far. That?s why we are reaching out to the forum to see if anyone has successfully removed the gears and exactly how they did it. We have tried to tap them out using a metal punch; tried using a small rod chucked in our large drill press to push the gears off the shafts; tried heating the gear and now having them soaking in WD40.

Can you please show some pics? Maybe we are missing something? My gears came off pretty easily.

[Rezendes]

One of the suggestions above , is to remove the grub screws and heat the gear with a propane torch. We did this without success. I limited the amount of heat I exposed the gear to, since I was concerned that I would damage the rubber seals. Which begs the question; do you remove the seals first? If so how? Do you drive the gear side of the shaft into the housing and slide the seal off the other end of the shaft?

[Rich]

One of the suggestions above , is to remove the grub screws and heat the gear with a propane torch. We did this without success. I limited the amount of heat I exposed the gear to, since I was concerned that I would damage the rubber seals. Which begs the question; do you remove the seals first? If so how? Do you drive the gear side of the shaft into the housing and slide the seal off the other end of the shaft?

You might not be able to take the seals off first if I remember correctly. You are correct, the shaft on the gear side needs to be driven into the housing. If I remember correctly the shaft has a bigger diameter just before the bearing on the seal side. I would say heat it up more, it's a tight fit. If you have a vise, open the vise just enough for the shaft to pass between the jaws. Place the housing on top of the vise jaws with seal side down. Heat the gear and tap the shaft down, this should take care of your problem. Heat only the gear, this will expand the gear. I know the shaft will be heated as well but just focus the heat on the gear. If you have a small butane torch use that instead of a propane torch so you can focus the heat on the gear.