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| Noisy power from typical backup generators |
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| Johnny B Good:
@IDEngineer I don't think the compressed air technique would work with a single cylinder 4 stroke ICE. It might be ok with a twin cylinder two stroke engine. I know compressed air starting is commonly used in large marine diesel engines but they generally have 4 or more cylinders to work with. However, since I've no experience with such compressed air starting and even less knowledge about the details involved, I could be wrong. It's just a gut feeling I have that you need more than just one cylinder for compressed air starting to function reliably. TBH, I started losing motivation to continue my DIY electric start once I'd figured out a less painful technique to prime the carb float bowl by cranking not so energetically on the pull starter with the ignition off for about four pulls before finding the top of the next compression stroke and taking it just 'over the hump' before turning the kill switch to the run position and giving the starter cord a very firm yank with a very high probability that it will fire up "First go" rather than snatch back. My problem had simply been a lack of finesse, wasting energy in priming the carb leaving me too little energy left to crank it fast enough to avoid the kickback risk by the time it was finally ready to start. A fuel lift pump priming lever would have made life so much easier for both me and the service life of the starter cord. Still, for just £99,95, I suppose I should be grateful they'd even equipped it with a recoiling starter cord. :-DD The comparison to the bendix mechanism's function did come to mind, along with the free wheeling starter pinion clutched onto the crankshaft of the Honda CB160's twin cylinder engine using a cunning spring loaded three ball bearings mechanism to provide the free wheeling function which worked surprisingly well as an alternative to a bendix or a pre-engaged starter setup. I'm considering the possible use of a small starter motor transmitting its drive via a rubber faced wheel pressing against the flywheel rim. At its simplest, it could just be a lever operated swivelling of the starter on a hinged bracket against the flywheel, the pressure of which would also force a contactor closed to switch the starter motor on. The charm of this being that no starter ring is required on the flywheel making it applicable in principle to almost any small inverter gensets that otherwise don't have a manufacturer supplied electric starter kit option. An alternative to swivelling the whole starter motor would be to use a rubber faced idler wheel that can be pressed (or pulled) into contact with the starter drive shaft and the rim of the flywheel. Of course, this assumes there won't be any insurmountable problems securely attaching the mechanism onto the engine itself. At this time, this is an imponderable requiring careful examination of my options once I have the case covers off to actually see what mounting options there might be, if any. This just a bit of a brainstorming on my part which will probably all amount to nothing in the end. |O John |
| james_s:
--- Quote from: Johnny B Good on February 28, 2021, 04:11:40 am --- TBH, I started losing motivation to continue my DIY electric start once I'd figured out a less painful technique to prime the carb float bowl by cranking not so energetically on the pull starter with the ignition off for about four pulls before finding the top of the next compression stroke and taking it just 'over the hump' before turning the kill switch to the run position and giving the starter cord a very firm yank with a very high probability that it will fire up "First go" rather than snatch back. My problem had simply been a lack of finesse, wasting energy in priming the carb leaving me too little energy left to crank it fast enough to avoid the kickback risk by the time it was finally ready to start. A fuel lift pump priming lever would have made life so much easier for both me and the service life of the starter cord. Still, for just £99,95, I suppose I should be grateful they'd even equipped it with a recoiling starter cord. :-DD --- End quote --- Mine usually starts on the first or second pull, no aggressive yanking, no particular technique, I just turn on the fuel/ignition switch, set the choke, grasp the cord and give it a brisk yank as soon as I feel the pawl engage. The little Honda engines are fussy about fuel though, I always use fresh fuel, non-ethanol and put stabilizer in it. Unless I think I'll be using it again shortly I drain the carb bowl before I put it away, it has a drain tube you can stick in a cup, open the drain screw and then pour that fuel back into the tank if you want. The carb jet is very small and easily clogged, if yours is hard to start try cleaning out the carburetor and use some fresh fuel. If you can't find a place to get non-ethanol pump fuel you can buy those cans of engineered fuel. They're to expensive for day to day use but it's fine for occasional needs. I remember my dad telling me that the Honda outboard motor he had on a dinghy didn't like stale fuel either, and I have a Honda powered pressure washer that is also very hard to start on old fuel. I don't know why they're so fussy but they run very well and are efficient as long as you have good fresh stuff in the tank. |
| Renate:
Yeah, getting fuel into the carb before cranking would be nice. I have an Onan 2.8 kW (that I don't use much). The first few seconds of cranking (after long disuse) are wasted. I would add a switch to prime the electric fuel pump but I'll have to wait until the next time I drop it. A friend has already added a switch to theirs. |
| Johnny B Good:
The problem I have is the need to spin the engine over to operate the fuel lift pump to refill the carburettor float bowl. The Parkside unit has the same drain screw and plastic drain pipe which simply exits out the bottom of the generator but it's a feature I don't need to use since I can simply shut the fuel off and let it run dry before putting it into storage. That's the (vital in this case) advantage of NOT combining the fuel tap with the ignition kill switch. Keeping those two functions completely separate neatly avoids any need to wear out a carb drain screw - just shut off the fuel after disconnecting the load and then wait the next 2 or 3 minutes it takes to run the float chamber dry. :) I wouldn't have this problem if Parkside had thought to provide a fuel lift pump priming lever or 'bulb' to pneumatically operate the pump to refill the carburettor float bowl without having to apply 4 or 5 gentle 'dummy run' pulls on the starting cord. >:( :( I suppose I should fit a fuel lift pump replacement that supports such manual priming to save the needless wear and tear on the starter cord and preserve my energy for a successful first time, every time pull on the starting cord. Such a feature would have put all thoughts of trying to upgrade to an electric starting system completely out of my mind. I think it's high time I did some research into this business of manually operating a fuel lift pump. I might discover that adding a "Priming Bulb" is simply a matter of teeing in a small bore rubber hose from a squeeze bulb into the engine (inlet port vacuum or crankcase pressure?) line which operates the pump. Apparently, after a duckduckgo search for the information I so craved on this subject (not quite the usual hunt for hen's teeth and Unicorn droppings this time), I discovered that such priming bulb setups aren't nearly as sophisticated as I expected. Indeed, after viewing a few youtube chainsaw repair videos on the subject, it's even more mind numbingly crude than I'd ever imagined. From what I saw, it seems all that's really needed is a priming bulb kit with a metre's worth of fuel line and a couple of T pieces to effectively put the priming bulb in parallel with the existing fuel lift pump. It seems to me that such an arrangement won't interfere with the fuel lift pump unless the priming bulb goes faulty hence my ordering a pair of 3mm plastic Tpieces (£2.28 delivered) and a "Fuel Lines with Fuel Filter & Primer Bulb for Tygon Craftsman Poulan Chainsaw" kit with two priming bulb pumps (£4.91 delivered) from UK based ebay sellers. Fingers crossed that I've ordered the right size of T adaptors to match the Parkside fuel line and one of the two 900mm lengths (2.0 and 2.5 mm ID) supplied with the kit. The £7.19 investment is a modest price to pay for easier starting. It should be just as effective as the four or five 'priming pulls' on the starter cord but without all the wear and tear on the cord and my well-being. I may have the fuel priming kit installed in a week or two's time. I'll let you know the result once I've had a chance to test it out. John |
| G7PSK:
I have built a number of alternator sets over the years mostly using stamford brand of alternator, now part of cummings power, I never had any trouble with noisey power from them and they use electronic AVR's or transformer type regulation on the smaller units. All the rotors have had a slight helical form to the windings which i understand helps with delivering a smoother waveform. |
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