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  #1  
Old 10-06-2018, 04:47 PM
n518jh n518jh is offline
 
Join Date: Jan 2015
Location: Sun City West, AZ
Posts: 25
Default RV-12 Hard starting issue

Recently my 2012 RV 12 with 400 hours has become hard to start in 90-100 degree weather. I end up after a few seconds of windmilling, pushing the throttle full in and then out and it usually starts. I have a aftermarket soft-start ignition module and that might be a problem, or the carbs. The question is , where to start to find the problem. Any thoughts?
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  #2  
Old 10-06-2018, 04:55 PM
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tomkk tomkk is offline
 
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I'd start by checking the carb floats.
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  #3  
Old 10-06-2018, 05:05 PM
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DaleB DaleB is offline
 
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Has the carb inspection/rebuild been done? I just re-did ours. It made a night and day difference.
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  #4  
Old 10-06-2018, 05:16 PM
n518jh n518jh is offline
 
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Thanks, I will check the floats and carb side first. Has anyone had ignition problems related to hard starting? just asking to see if that is also an option.
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  #5  
Old 10-06-2018, 05:37 PM
DHeal DHeal is offline
 
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Location: Windsor, California
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Make sure that when your CHOKE ("Starting Carb" in ROTAX parlance) is in the OFF position that the choke lever arms are resting solidly against their stops and there is a wee bit of equal slack in the choke actuator cables. Also be sure that both choke actuator springs are properly doing their intended jobs.

For cold starts, I use 1/2 to full choke initially -- be sure that the throttle is FULLY CLOSED. As soon as the engine fires, I feed in a bit of throttle and start easing the choke off. For warm/hot starts, I use no choke at all and just crack the throttle open. These procedures work very well for my RV-12 and others I have flown -- usually, you can't even see the prop move before its running.

Poor starting performance can also be the result of a tired battery or spark plugs gaps being too wide. The battery may seem like its spinning the prop well enough but it is not fully up to the task -- try a known good condition battery. Ignition trigger gaps could be checked as well to ensure that they are within spec.

ps -- I'm not sure if the aftermarket Soft Start modules work the same as the factory Soft Start modules on my 912 but my factory modules cause the initial starting RPMs to increase noticeably (couple hundred RPM?) a couple of seconds after the start as the start timing setting reverts to normal operating timing setting. Does your Soft Start do this?
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Last edited by DHeal : 10-06-2018 at 05:50 PM.
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  #6  
Old 10-06-2018, 06:18 PM
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Piper J3 Piper J3 is offline
 
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Is this first start of the day or restart after plane was already flying?
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PPL/ASEL 1970 - Sport Pilot since 2007
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  #7  
Old 10-06-2018, 06:47 PM
sf3543 sf3543 is offline
 
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Location: San Antonio, TX
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I had the same problem a couple years back.
Try putting an ice pack on top of the ignition modules for about 15 or 20 minutes when it wonít start.
If it starts after that the ignition module is probably bad. Itís possible one has been bad for a while and now the other one is going.
If thatís it, hold on to your shorts! They are expensive to replace.
Good luck.
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  #8  
Old 10-06-2018, 09:32 PM
RFSchaller RFSchaller is offline
 
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Location: Phoenix, AZ
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Steve,

Didn'tí your run up catch the bad ignition? Out here in Phoenix mine get scary hot in the summer, but after 6 1/2 years and 800 hours they hang in there. Given the replacement cost I have my fingers crossed.

Rich
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  #9  
Old 10-07-2018, 12:02 AM
n518jh n518jh is offline
 
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Location: Sun City West, AZ
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Thanks folks. I will try the ice pack on the ignition packs as well as the starting routine. If that works, then I am on my way to solving the problem, if they don't it's piece by piece. Now I need some hours with my baby to see what works. Mark
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  #10  
Old 10-07-2018, 09:27 AM
sf3543 sf3543 is offline
 
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Location: San Antonio, TX
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Rich
I always start the 12 with both switches on and after engine start I got the normal drop when checking ignition.
I talked to the folks at Lockwood and they talked about something in the modules that wouldnít reset but the ice cooled it enough to reconnect and then it would start right up. I really donít remember the specifics since it was about three or so years ago. Maybe someone here can chime in with more specifics.
At any rate it was basically starting on one module and that one finally gave up the ghost. Mine were the original ones before the soft start modules were available and had just under 400 hours when I replaced them.
Rotax used to have a kit to replace both modules for the price of one, to get the soft start modules out there, but there arenít any available any more and you have to buy individual modules to the tune of about $1000 each.
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