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Thread: JBM carb boots

  1. #1
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    Default JBM carb boots

    Hi guys, just wondering if anyone has seen this with a JBM carb boot. I bought these a number of years ago, they sat in the plastic container they are packaged in till last summer when I installed them on my Kitfox 4 rebuild. Last couple of flights I had some missing between 5050 and 5150 rpm. It seemed smooth below that and at 5350 was smooth as can be. I had another set of carbs rebuilt, and got them back yesterday. I figured I would swap them out and see if the miss went away. When I started to pull the first carb off, the boot seemed real flexable, and then I saw the boot was cracked on the bottom part. Pulled it off, and this is what it looks like. I wasn't really reefing on the carb today. For sure didn't pull on it hard enough to tear this if things were as they should be. I wonder how bad it was torn yesterday when I was flying, the miss was still there, but not real bad, kind of intermittent. I would be supprised it would run at all like this. It was torn on the bottom though, and the weight of the carb would hold it together somewhat, but still... It must have opened up some more today when I pulled the carb then it had been. I swapped out a good old one, and see if the miss is there next time I fly. Any thoughts? JImChuk
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  2. #2
    Super Moderator Av8r3400's Avatar
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    Default Re: JBM carb boots

    Had mine on the plane for 5 years now and they look like brand new.

    I'd give JBM a call and see if they will warranty them. I've had good luck with their customer service...
    Av8r3400
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  3. #3
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    Default Re: JBM carb boots

    I did start an email to them this evening, but didn't finish it. Maybe will call them tomorrow. The boots sat on the shelf for maybe 8 years, although they were in the sealed package I got them in. Not sure if the age made a difference, but they are still pliable, not stiff or weather checked or aged looking at all. I don't think they would look any different if I had bought them new last summer. (other then the crack maybe) JImChuk

  4. #4
    Senior Member Dusty's Avatar
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    Default Re: JBM carb boots

    The only failure I have seen on jmb boots is over tightening which yours doesn't appear to be.
    generally a good product.

  5. #5
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    Default Re: JBM carb boots

    Well I did end up sending an email to JBM today. Explained what the situation was and wondered what his thoughts were. He said something was pushing the carbs up, to cause that, and he would send me an invoice for two more if I wanted him to. I can't really blame him I suppose, they had set on the shelf in original packaging for 8 years. Ended up sending him a picture of my installation, and wondered if there was anything he could do for me. If he had said I'll knock off 10% even, I'd have felt better. He again said there was something wrong with my installation, and that he wouldn't be able to satisfy my needs in this installation, and he wished me luck in finding parts that will. Kind of stuck though, they are 40% under rotax's price. (on second thought, did he tell me to go somewhere else) Just to be clear, I'm not really bashing JBM, just saying what happened, and that's that. Below is my second email to him. JImChuk


    On the kitfox that I have, there is just a small airfilter on the back of the carb, and nothing at all pushing up on it that would tear the boot. It is possible that the boot tore when I was installing or removing the carb at one time or another, but I would think it would have taken much more force then I ever applied. I have about 15 or 20 running hrs or so on the installation. I don't blame you for not wanting to stand behind the product after it sat in it's original packaging for 8 years, but I would be happier if you would offer me some sort of discount if I order two more. Here is a picture of my installation. I wasn't totally done with things then, but the carb location and things attached to it are the same. Thank you for your consideration in this matter. JIm Chuk
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  6. #6
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    Default Re: JBM carb boots

    The way I look it it as you got 10 years out of a 5 year rubber item!

    Kitfox sells stock ones if that makes a difference.

  7. #7
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    Default Re: JBM carb boots

    Well as I think I said, I put the old Rotax carb boot on in place of the JBM one that went belly up. Yesterday I flew for 1.3 hrs and there was no missing with the engine. So it seems for the moment, all is well. JImChuk
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