danny_galaga

Yeah, very rough guide for this sized starter is to allow maybe 500 amps. It's one of the reasons in the end I was happiest with a mechanical isolator over a relay. Pretty much no voltage drop or current draw. Every watt of energy to the starter. Faster starts, and battery recharges as quickly as possible 🙂

Actually misremembered that. Cable does go to back of starter. Negative bus bar is fed by a wire straight from the negative battery terminal

I have the negative battery lead going to the back of the starter. Because the starter was designed for the BMW 650, it has a couple of superfluous lugs on the back. They bolted to the BMW crankcase but just hang out in the air on the Rotax. Perfect for bolting the cable on. Gets the current right where you need it most, at the brush box of the starter for the shortest run. Then a lead goes from there to the negative bus bar on the instrument panel.

My alternator is 204W by the way. Even the regular relay is using more than 10% of the alternators output just being there. Let alone 60W 😲

Just when I was thinking I'd consider it 😄 I'm a big fan of every single watt of energy going to the starter when you are starting. That big lump of a battery is basically there just for that. It's also why I wasn't keen on a regular isolator relay/solenoid although that will draw less than the SSR it looks like (maybe 2a X 12v = 24w). In both cases, they are losing power all the time your key is on. 60w reliably (I guess 60w at start, and less otherwise but start is when you want the least loses), or 24w continuous with chance of contacts burning or fusing. Also that particular SSR has rather small terminals. Big cables tend to pull/twist so I wouldn't want them just hanging off those terminals. Maybe there's a bigger one, but then it might be dropping even more watts. Nope, I'm very happy you guys convinced me to put SOMETHING there. And I'm extremely happy with the isolator I went with, even though if I spent more time on it I concede I could have made the cable run a bit shorter. The cable run is still probably less than half what the kit suggested, and maybe a 1/4 or less of what I've seen in planes that have to have the battery rearwards! All in all, pretty pleased with myself 😊

Welcome aboard! I used to dream of a Quicksilver and I reckon I would have bought a new kit a few years ago if it weren't for the double whammy if Rotax pulling out of two strokes and Quicksilver having financial difficulties at the time

I should point out that if I put an isolator on the firewall, with a mechanical extension into the cabin, that would take about the same amount of cable as installing it in the instrument panel like I did. The battery is inside the plane..in the panel in this is just as good, and one less thing to go wrong (the extension). If the jigger faced the right way, it would be ideal because there's not one centimetre of extra cable used (it bolts directly on the battery terminal) . Facing the right way, I could have run a tube straight from that to the instrument panel

I think 100 amps would be a bit marginal,even for the motorcycle starter the 912 is using. My isolator is rated at, I think 1000amp for 20 seconds and 100 amp continuous. That's overkill, but it's actually the smallest I could find 😄 Fully agree on having it on negative, but once I decided to upgrade my isolator, it was much easier to mount on the right hand side, which is the positive side if my battery. The lead pretty much goes from the battery to the isolator without touching anything, so no danger of a short there (which is generally why we like the isolator on the negative) .

I thought I had posted a pic of the isolator on its own, but maybe it's another thread. My isolator is the same mechanically as the one you posted. In fact if you posted a Narva, it's exactly the same. Instead of a switch shaped like a key, it's a switch shaped like a knob. In fact, the knob comes out just like the key. If I lost the knob, and couldn't easily find that style in a shop, then I'm pretty sure the Narva key would fit straight in. In any cae, an isolator is a switch. It really doesn't matter how it works, so long as it does. I think one of the guys here has some sort of home made knife switch with a rod attached. It's all good. So long as the contacts can handle the cranking amps for however many seconds. It's not like you are normally opening it under cranking conditions with big Frankenstein arcs spraying out of it! In fact, almost anytime you use it (extra safety feature when plane is parked) there is zero current going through it. Or zero in my plane anyway. The isolator on my instrument panel is about 200mm from the battery by the way. Edit, maybe not exactly the same, now I look at the picture but you catch my drift. It is an isolator. For my battery.

All sorted. Case closed 🙂

Dammit, where's my "Beat Skippy over the head with a big stick" emoticon 😄 To sum up this whole thread: 1. after doing pretty much all my electrical, I realised I hadn't thought of putting in any kind of isolator in. This happened when there was a discussion about starters getting stuck on. 2. Being very pragmatic (read- extremely lazy) I decided I really only need to isolate the starter while on the ground. I sniffed out the easiest thing I could find that would fulfil the task - the jigger. Since im on the ground, I rationalised, it doesn't have to be fancy, or especially accessible. 3. Recent events gave me pause for thought. The big thought was this- Perhaps I have an emergency in the air. Id decided the jigger is really only for ground use. But with a cabin filling up with smoke, there's no way I'm not going to try and isolate the battery. Which means I would be scrabbling around behind the instrument panel. 4. JOHN DENVER ANYONE? 5. DONT BE LAZY. (Dan beats HIMSELF over the head with a big stick) 6. I bought a panel mounted isolation switch. Go back a page or two and I have posted a pic of the installation. 7. It occurred to me I might as well put the jigger back because it's a pain in the ass trying to disconnect the negative on the battery because it's tucked up behind the instrument panel. 8. Here we are. 9. Incidentally, if the jigger had been facing the right way, I could in fact have extended it with a rod, sticking out of the instrument panel. 10. But it wasn't facing the right way.

This lil jigger basically does that. If you unwind it a few turns, it's as if you've taken the lead off. It's basically two lugs held together by a bolt with a handy knob molded on. I would normally always take a negative off if working on the electrics. I can just see me arcing a spanner on the aileron cable. Then I'd have to replace all that for my laziness. I put the jigger back on because the battery is in a tedious position, behind the instrument panel.

Yes, I would suggest Repco for your spark plugs.

Incidentally, I wired up my accessories wrong when I installed the new master switch. So of course I had to undo the negative side again, where I had just removed my dinky lil battery isolator. So I thought it's going to be a pain in the arse undoing the negative any time I have to work on the electrics. So I put the lil isolator back on the negative. So now, if I want I can isolate the battery completely very easily.

I think I forgot to add the starter solenoid here. This is the same part, but without the roTAX sticker on it 🙂 Denso 182800-1950 I bought it from a kart shop in Australia, but I've forgotten which. Funnily enough, you can buy the same solenoid from the Rotax kart engine supplier too, still cheaper than the 'aircraft' version 😄 The beauty of using the same part (as opposed to something electrically equivalent) is that if you already have the same solenoid (and you probably do) then this is a drop in, without drilling new holes or changing cables. UK supplier (not exceptionally cheap with freight) https://ecclestonaviation.co.uk/product/nippon-denso-starter-solenoid/ Rotax kart supplier https://www.rotax.com.au/shop/item/starter-relay-evo I may have got mine here. https://kart-store.com.au/products/rotax-evo-starter-relay-assembly

Yes, you could say the available choices for 912 carb engines has now doubled, so that's twice as good for those engine owners 😀 I will still choose shell.

Inside the plane, on the firewall. Rotate your screen 90° anti - clockwise for correct view 🤪

Best $7 I ever spent 😊

Not so much relaxed, but not inclined to go further with it. You have done some research on it, you may need to go to the ACCC or similar.

What I'm thinking might happen is over a few weeks, which is how long since last time, a fair bit of fuel syphons away from the gascolator, since the fuel pick ups are from the top. Running the boost pump for a few seconds will pull fuel into it. Next weekend I'll do a drain straight away and see what I get. Then try the boost pump.

Hmmm, I'm wandering if it does need the boost pump? Next I'm.there I'll run it for a second and see if that makes a difference. And reading up on them it seems it shouldn't matter if you used the boost pump because all the water and crap will have dropped into gascolator as it passes through. I'll report back 🙂

Yes, pretty I hooked it up the same way. But who knows, it was years ago now 😄 The engine is running fine. This is all leading me to the conclusion there is something wrong with the gascolator. I wouldn't be surprised, just another kick in the head with this 'friday job' kit...

This is how it's hooked up