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Old 05-22-2017, 06:48 PM
Miller Thriller is offline
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3w 75IUS Engine trouble

Hello Gents,

I have taken some pictures of the reed and I need someone to tell me if this looks like the gap is too big.

I've read a lot about this issue of these engines not starting and I think it may be an air leak from the block or too much gap in the reed.
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Old 05-22-2017, 07:57 PM
torquen is offline
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That gap is completely normal.
Garrett
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Old 05-23-2017, 02:30 AM
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until the gap is les than 0,5mm then is ok.
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Old 05-23-2017, 08:06 AM
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OK,

I just ordered another spark plug to see if that changes anything. Im getting the famous symptom of the engine firing when choking , but won't start when I un-choke the engine. If I advance the throttle about 50%, it will sometimes start and run, but won't run once I take the throttle back down below 50%. I'm definitely getting fuel to the carb since it's getting pretty wet. I haven't checked the timing yet. Needles are set to Factory settings and doesn't change much if I move them.
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Old 05-23-2017, 08:44 AM
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Had one of these motors with the same problem. Sent it in for repairs. They sealed the reed block on BOTH sides with silicon or RTV. Seems there was a problem with the reed block developing an air leak due to small warping. Was a real bear to start before the repair.
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Old 05-23-2017, 08:52 AM
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Thanks Bullardrm,

I'll give that a try.
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Old 05-23-2017, 08:55 AM
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My first 3W was impossible to start. It was the reed block seal. I've used an anaerobic sealant (permatex makes it) on all my motors since and there have been no issues. As mentioned, both sides of the block unless you have a good gasket between the carb and block - in that case just between the block and motor. Do not over tighten the bolts.
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Old 05-23-2017, 08:58 AM
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I have Permatex 85420 Fuel Resistant Gasket Dressing and sealant. Will that work?
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Old 05-23-2017, 09:09 AM
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I'll get the Permatex Anaerobic Flange Sealant. I've read this stuff works really great. I have a feeling you gents are right on the money with this.

Thanks everyone for your help and wish me luck.
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Old 05-23-2017, 09:10 AM
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This is the stuff.
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Old 05-23-2017, 09:16 AM
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Thanks daddysam,

You recommend letting it cure for the full 24hrs?
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Old 05-23-2017, 09:30 AM
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. It doesn't really harden - at least not for a long time. I've taken carbs off after a season of flying and it was still gooey. You want a very thin film and make sure it doesn't get in the pulse hole or channel. I've never used the surface prep activator - hmm, maybe that is why it stays flexible!
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Old 05-23-2017, 11:32 AM
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Ok, I just picked this up from the auto parts store. Should I place some sealant around the reed carrier as well as the block?
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Old 05-23-2017, 11:49 AM
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I would put a very thin film on The surface of the crankcase and the carb block. You should be good to go. If you choke it and rock the hub back and forth against compression you should see fuel come through the gas line.
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Old 05-23-2017, 11:52 AM
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Thanks Daddysam, Will do!
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