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  #1  
Old 09-13-2017, 08:13 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 2,057
Default Carb Overhaul Issue

I recently sent my carbs out for overhaul to a well known western USA repair center. When they came back my engine was extremely hard to start. Today I removed them and disassembled them. I found the shop had swapped the starter circuit (aka choke) modules to the opposite carburetors. When I swapped them back the engine kicked right over like it used to. FYI the symptoms were really long cranking to start and about 10% increase in cruise fuel flow.

I don't want to identify the shop because it's probably an isolated event and I don't want to get into a pointless legal battle with them. Suffice it to say don't trust any shop will get it right.

Last edited by RFSchaller : 09-13-2017 at 08:21 PM.
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  #2  
Old 09-13-2017, 08:32 PM
R100RS R100RS is offline
 
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Good to know. Thanks.
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  #3  
Old 09-14-2017, 06:26 AM
AZLeeJay AZLeeJay is offline
 
Join Date: Dec 2013
Location: Phoenix
Posts: 99
Default

regarding carb overhaul in general...
How many hours were on the carbs?
Did they send the old parts back and if so was there obvious wear?
How difficult was the synchronization after overhaul?
Thanks in advance,

I have 400hrs on mine and they have never been overhauled or even disassembled and inspected but continue to run well so I'm reluctant to mess with something that appears to be working well.
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  #4  
Old 09-14-2017, 07:10 AM
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Infidel Infidel is offline
 
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I've rebuilt two sets of 912 carbs due to ethanol and can see where the choke modules could be swapped by a novice as they are actually marked "L" for right and "R" for left-if I remember correctly. It's been a few years. Good to hear you found the problem.
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  #5  
Old 09-14-2017, 10:12 AM
RFSchaller RFSchaller is offline
 
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I had 580 hours on the carbs when they went out for overhaul. The only parts they replaced were the O-rings, diaphragms and floats. The floats were within the 7g limit so I had them returned to use as spares.

The carbs did synch when I reinstalled them with the modules on the wrong carb bodies. It just started really hard and used more gas.

I marked the carb domes with an R and L when I removed them, and I noticed the domes had been switched when I got them back. That was my first clue things might not be correct. I notice the ROAN learning video suggests working on the carbs one at a time to prevent swapping parts.
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  #6  
Old 09-14-2017, 10:15 AM
Piper J3's Avatar
Piper J3 Piper J3 is online now
 
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Location: Hinckley, Ohio
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Quote:
Originally Posted by AZLeeJay View Post
I have 400hrs on mine and they have never been overhauled or even disassembled and inspected but continue to run well so I'm reluctant to mess with something that appears to be working well.
At the very least I think I would drop the float bowls to look for debris and also weigh the floats as part of annual condition inspection.
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  #7  
Old 09-14-2017, 01:03 PM
AZLeeJay AZLeeJay is offline
 
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Quote:
Originally Posted by Piper J3 View Post
At the very least I think I would drop the float bowls to look for debris and also weigh the floats as part of annual condition inspection.
I do that, just not complete disassembly.
Thanks for the response, I think I'll wait another hundred hours before overhaul.
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  #8  
Old 09-14-2017, 01:34 PM
funflying funflying is online now
 
Join Date: Oct 2006
Location: arvada, co
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Default My 2 cents

I too just went through a profession ( which means $$) carb/s overhaul as I was at the 200 hour inspection interval but next year I would be at the 5 year rubber replacement interval.

After discussion my situation with the shop I decided to do the overhaul early. Received the carbs back and all looked good and the parts replaced were also returned. Everything looked fine and believe me it was tough to "fix something that wasn't broken."

The only thing needing attention was the plastic bushing on the control arm of one carb where the spring rides.

FYI I maintained the control arms in the same position prior to removal and when reinstalled the carbs were still in sync.
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  #9  
Old 09-14-2017, 09:22 PM
RFSchaller RFSchaller is offline
 
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Pat, I sent you a PM.

Rich
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  #10  
Old 09-16-2017, 09:33 AM
Jolly Jolly is offline
 
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Location: San Francisco, CA
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The 200 hr. is only an inspection. There is nothing in writing on when to rebuild a carb.
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