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Single point ground
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Ed Holyoke |
If I read the OP correctly, there is now a new NL starter on the ship - which should spin a std compression 320 fast enough to taxi around with. If the heavily geared NL is struggling to get over the hump, but have 10+ volts at the starter post then you must have a really bad ground. Might try a single jumper from the neg battery post to the starter case (leaving the originals in place) and see if it improves performance.
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KADriver,
That problem should manifest noticeably different symptoms, if you know what you're seeing and hearing. If the start contacts of the ignition switch are flaky and dropping out, you should also hear the start contactor drop out along with the switch contacts, and the sounds from the engine/starter will be different. You'd also see battery voltage return to near no-load levels. To the OP, Fat welding cable is very flexible, readily available locally, and serves well in many homebuilts as battery/starter/ground cable. The only thing that should be in the ground path from starter/engine case to the battery negative should be a brass or copper feedthrough bolt on the firewall, if the battery is aft of the firewall. There have been cases where starters (and alternators) have had poor grounds due to heavy paint or powdercoat on the appliance, the attachment bits, or the motor itself. When doing your measurements, be sure the meter negative is directly on the battery post (not the clamp or bolt). Work your way along the ground path, on both sides of all joints, with the meter positive lead. You should never see more than a half volt or so (in the extreme) between any point from starter case and the battery negative post, while the starter is under load. |
ETX900
Probably not the same problem. I had a PC680 that was just struggling to turn my angle valve engine over so I swapped it out for a ETX900. Now I save fuel by taxiing to the runway with the mags off. 😜
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Key Switch Technique - May Be the Solution!
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After the 1st successful start, I intentionally shut the engine down to try a 2nd time. The same key technique gave me the same success. I know one sunny day doesn?t make a Summer, but I am encouraged. I will keep everyone posted. Dale |
Toss that flakey switch and install a couple of toggles and a pushbutton. :)
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Key switches look cool, do multi functions, give the appearance of security, but have an insidious history of exactly what youve encountered. |
Great it appears to work now, but can anyone explain why? If the primary symptom is the inability to crank over the first compression stroke, then how does an intermittent contact on the key switch do that? The key activates the starter solenoid, and the starter solenoid sends the big power to the starter. the starter solenoid is either on or off. Bad contacts in the key switch will not alter the amount of power running through the main plunger contact in the starter solenoid. The only way I can see this happening is if the solenoid makes/breaks contact because of the poor signal from the key. But this would manifest as a buzz or chatter of the solenoid, which would be obvious to the pilot.
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