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Carb coming lose - 4/10/2008 4:17:08 PM   
BUDMAN27



Posts: 1114
Joined: 3/28/2006
From: Galveston, TX, USA
Status: offline 		Been having some truble with my Super Tigar .40 carb coming off in flight. The little half moon bolt has started to eat into the metal as you can see. My buds at the flying field have thier ideals on how to fix. Just wondering what you guys thought I should do other than buying new stuff. Thans in advance.

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RE: Carb coming lose - 4/10/2008 4:37:35 PM   
luv to race


 

Posts: 449
Joined: 12/10/2002
From: Liquored, FL,
Status: offline 		Bond it in the case with high temp RTV, maybe JB Weld. There is obviously a tolerance issue. We are to guess that the carb is a lose fitting in the case hole.. yes? So..that gap should be filled. Does the little nut work itself lose during flight, allowing the carb to come out? Maybe use some red loctite on the nut after you tighten it up?

(in reply to BUDMAN27)
       Post #: 2

RE: Carb coming lose - 4/10/2008 4:53:34 PM   
daven



Posts: 6650
Joined: 12/7/2001
From: Andover, MN, USA
Status: online 		Clean thoroughly and JB weld her in for good.

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(in reply to luv to race)
       Post #: 3

RE: Carb coming lose - 4/10/2008 4:57:50 PM   
BUDMAN27



Posts: 1114
Joined: 3/28/2006
From: Galveston, TX, USA
Status: offline 		No you don,t have to guess Randy. It is a little lose. I,m relucktant to use JB Weld ,because I used it on a Nelson outer shell before and it came apart. Maybe some good lock tight will do the trick. It just bothers me to see how much metal is geting gouged on the side of the carb neck. I wished Super Tigar would of done the same thing that OS did and put two screws to hold the carb on.

(in reply to luv to race)
       Post #: 4

RE: Carb coming lose - 4/10/2008 5:42:39 PM   
luv to race


 

Posts: 449
Joined: 12/10/2002
From: Liquored, FL,
Status: offline 		Nelson "outer shell"? what's that...? are you talking about the muffler? If that's the case, I'd guess the surface wasn't cleaned well enough. Especially if the engine/muffler had been run before. The bonding surface would be extremely contaminated, and would need major cleaning if and expoxy was to adhere (JB Weld included). But in the carb area of an engine, raw fuel and oil would be easy to clean (as Dave recommended).

However, I'd try to use the little tightening bar that is in the motor. If the nut coming lose is the issue, loctite the nut and tighten the crap out of it. Did you notice if the nut works itself lose? I assume that when you land the carb is hanging out of the engine, right. And the little bar/nut thing is still there? If the little bar/nut is still tight... gluing the carb in may be the only option (other than just buying a new engine).

(in reply to BUDMAN27)
       Post #: 5

RE: Carb coming lose - 4/10/2008 6:55:25 PM   
Ed Smith


 

Posts: 2807
Joined: 12/29/2001
From: Brantford, ON, CANADA
Status: offline 		It could be that the carb body is so worn in the clamp position that the locking bar will not lock it. As the lock nut is tightened it pulls the bar through too far and runs out of thread and locks against the end of the thread rather than the carb body. If you see what I mean.

Try wrapping a piece of shim around the carb body. You will be surprised what a piece of 0.002" shim will do. Or, a washer under the locking nut to push the nut away from the thread.

Or as Randy says, screw it, buy a new engine!

Ed S

(in reply to luv to race)
       Post #: 6

RE: Carb coming lose - 4/10/2008 7:07:39 PM   
ChrisAttebery



Posts: 311
Joined: 9/15/2004
From: Gilroy, CA, USA
Status: offline 		Use 5 minute epoxy. Clean the parts thoroughly with acetone first.

In the early 90's I had a Picco 80 that was doing this on a regular basis. John Finch from RCBM wrote an article on speed secrets around the same time. One of them was that he glued his carbs in his motors because of the very problem you describe. I tried it and it worked. End of problem.

When you need to remove the carb just heat the case gently with a propane torch. The epoxy will soften right up.


Chris


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(in reply to Ed Smith)
       Post #: 7

RE: Carb coming lose - 4/10/2008 8:07:59 PM   
jaka


 

Posts: 4348
Joined: 12/11/2001
From: Upplands Vasby, SWEDEN
Status: offline 		Hi!
If the carb comes loose ...then you haven't tighten the bolt enough! Also be sure you balance the prop.

_____________________________

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MVVS, Motul "Micro" all synthetic oil

(in reply to BUDMAN27)
       Post #: 8

RE: Carb coming lose - 4/10/2008 10:04:03 PM   
BUDMAN27



Posts: 1114
Joined: 3/28/2006
From: Galveston, TX, USA
Status: offline 		Thanks Chris I think out of all the salutions mention so far I like yours the best. Jaka I have the bolt tighten. If you look close at the pic (sorry its a little out of focus) you will see it has a gash in it from it beating the H out of it self. I just beleave this is not a good way to hold a carb in.

(in reply to jaka)
       Post #: 9

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