bipesd

I want electric start on my scale Donzi. These are commercially available, but the price is more that what I paid for my new Zenoah engine. I wondered if I couldn’t build my own out of some spare parts. I think I’ve come up with a working starter for less than $10 in hardware store parts. (Admittedly, I spent a few dollars more than that in development, as I went through some trial and error. But not much more.)

I removed and disassembled the stock Zenoah recoil starter, thinking I would reuse the engage/disengage mechanism. I set aside the case, rope, handle, and recoil spring.

I scrounged some old Associated RC10 spur gears and fitted one onto the back side of the recoil pulley. I centered it and attached it with some small screws and a couple of nylon spacers from the hardware store. I inserted an RC10 rear axle bushing into the center of the gear (not shown in the photo) and reassembled the recoil pulley, engine engaging mechanism, and related parts onto a ¼” bolt, using some nylon spacers from the local hardware store where appropriate. The photo gives an idea of what I mean, although the end result was a bit different (remember the trial and error part?).

I disassembled an older, unused cordless drill, discarding the case, trigger, keyless chuck, and clutch. (Actually, the clutch was disabled by removing the clutch adjusting parts and repositioning a shim in the gearbox.) Basically, what were left were the electric motor, gearbox, gearbox mounting screws, and chuck securing screw. I bolted another spur gear onto the gearbox shaft and secured it with an appropriate nut and the securing screw (left hand threads) and washer.

I cut an aluminum plate of the appropriate size and drilled holes using the original recoil case as a template for the mounting holes. I centered and drilled a hole and bolted the original recoil sub assembly with added spur gear to it. I likewise located and mounted the gearbox/electric motor assembly. I ended up adding a third gear to match rotation of the drill sub assembly such that operational torque would tend to tighten, not loosen, the spur gear on the drill sub assembly. A pinion gear would have been smaller and more elegant, but it was easier to use another spur gear and bushing on a ¼” bolt, much like the recoil assembly. Of course care must be taken in locating all of these gears so that they mesh properly. Finally, I used some long metric screws and 1½” of spacers from the hardware store to mount the assembly on the back of the Zenoah.

I haven’t actually started the Zenoah yet, but bench tests show that a 12v battery pack turns the engine over nicely. The mechanism engages and releases just like using the pull cord. I think it will work! I definitely spent more time on this than if I would have used a ready-made kit, but this was more fun and way less expensive.

nshumway

In my experimenting, I made a similar version from parts of a stock pull start and had problems in breaking the plastic part of the recoil starter that engages the motor. I wasn't able to get the part that engages the motor to retract quick enough when the motor started and it would always stall and break. I'm interested to see how yours works. I am working on a starter that still retains the pull start and have other items and www.nshumway.com

bipesd

I don't see why that should be an issue. The engaging mechanism has a ramp on the back side. When the engine starts and the rpms of the engine exceeds the rpms of the starter, the cogs on the engine should ride up the backside of the ramp and push the engaging mechanism back away from the engine. This is exactly the same operation as with the pull starter. You don't have to instantly react when using the pull starter. Of course this is all speculation on my part. I guess I will need to gas it up and give it a try.

martno1fan

that looks very good if it works i can see a lot of people copying your design maybe you should get it copywrited now and you could make a fortune!!!. happy christmas!!

Euan

Hello,
nice work mate,well done,i,ve just received a Fema on board starter for a friends boat and it was horribly expensive.
i wish i had seen yours first.
keep up the good work Euan.

OLD_SLOW and in the WAY

i have a spring starter on my G62 for my plane that uses a one way needle bearing that stays engaged on the shaft untill it reverses direction (starts) so lose the spring then make a mount for the gear drive

B & B ZENOAH SPRING STARTER $51.95
Specify: G62 or G45
Replacement springs $12.95
This new custom designed Spring Starter, with its stronger spring, will give you all the power required to start your Zenoah G62 or G45. It also has a much larger "Torrington" clutch bearing to give you years of service.

[link=http://www.bennettbuilt.com/B&bstrt.jpg]starter set bearing[/link]

bipesd

Well, I gave it a try tonight. As this is a brand new engine, I hit the starter a couple of times for a few seconds each without the engine starting. On the next try, the engine kicked back and broke the center idler spur gear along the line of the gear's mounting holes - the weakest part. My mistake was in trying a smaller 9.6v battery pack, which didn't turn the engine over fast enough. I located a FEMA catalog and see that they warn about this exact problem: "For the secure starting of the internal combustion engine it is necessary that the starter engine starts at the activation of the engine immediately with full power to prevent the kick-back of the combustion engine". They even offer kick-back dampers for some of their starter models.

Unfortunately, I'm out of spare spur gears. I have some on order and will try again with a 12v battery.

gasfreak

My Feedback: (13)

are you going to try to operate this starter remotely with your radio and if not whats the point

bipesd

Yes, definitely.

BUDMAN27

Its people like you that make this hobby so fun bipesd. Thanks for your can do attitude.

bipesd

Success!

I replaced the broken spur gear with a Robinson Racing gear that I also reinforced with a fender washer. I also used a higher-voltage battery pack. I started the engine a couple of times. There is no problem with the mechanism disengaging once the engine starts. I had to crank the engine quite a lot and also flooded it once. Not sure if this is because the engine is new or because of my inexperience.

I may have figured a way to key the shaft of the drill gearbox so that I can run it reverse without the spur gear loosening. That will let me get rid of that third idler gear and simplify things a bit.

Incidentally, even if you don't have a spare drill around, bargains can be found. I picked up one of these Coleman 18v drills with 2 batter packs today for $19: http://www.partsamerica.com/ProductD...umber=PMD81292 You can't buy batteries for that.

pete_486

hi Euan how did the fitting of the fema kit go?.............Pete

rctrailer1991

It looks really good! I don't think it has problems!!

danielplace

If you used a EZ start pawl nut on the flywheel then all you have to do is spin a center dog the pawls fly outward centrifugally when the engine starts and disengages the engine from the starter automatically. I am sure the design would be simpler more compact and sure to work properly everytime.

Justaddwata

My Feedback: (3)

Guys - thread is 6 years old

kerosenedevil

I'm looking for a electric starter for my g45 .. I have 2x g23otu on my ziroli b25 and 1x g45 on the way for my giant mustang . Would love electric start anything come along since thread was started . I don't mind paying really . I'm terrible at engineering