Michaelvg11

No matter how tight I screw on the muffler and how much lock-tite I use, after a couple flights, it still becomes loose. It's been doing it since I got it. What am I doing wrong. Any ideas? I have the Saito 180.

daveopam

My Feedback: (9)

It's a common problem with an easy fix. Wrap both ends of the pipe with Teflon tape. (the stuff a plumber would use). I use about 5 wraps. Then tighten it best you can. The tape fills the gaps in the threads. This keeps the muffler from vibrating loose.

David

Michaelvg11

Thanks. I have that tape in my tool box.

jetmech05

lock tite breaks loose with heat.....run the engine with the muffler on and tighten the muffler while its still hot

wsantore

My Feedback: (8)

Michael,

David's recommendation is sound. I use the following method on my Saitos with success. Clean fittings (both parts) with alcohol. Wrap with teflon tape. Assemble and and tighten firmly. Start engine and warm it up (get exhaust and muffler hot). Shut down and immediately snug the lock nuts again. You are now good to go.

good luck,
Bill

Michaelvg11

Thanks for those great tips guys.
Will give it a try.

JohnMcGowan

My Feedback: (15)

ditto on what jetmech says. Ive tried the teflon tape on my 180 and it didnt stand up to the heat, the tape just melted away.
What worked for me was to clean the threads good to get all the oily residue off, coat both surfaces with copper atv silicone that you can get at an auto parts store, let the engine warm up good then snug it all down good while things are warm. It took about 2 or 3 cycles of tightening while hot to get mine where it wouldnt back off any. Just be careful and #1, dont burn yourself, and #2, dont strip the threads out.
Hope this helps you,
John

gbarnes

I tried all of the above solutions to no avail. I even drilled the muffler and pipe and tapped it with a 4-40 bolt. Sheared the bolt in three flights. I sent the motor back to Horizon and they found that the front and rear bearings weren't spinning properly. You would never had known it. No detectable vibration at all when it was running. Got the engine back and it was like a new engine. Much more power. I thought they had finally fixed it, two flights later, the same problem. I tried a couple of other fixes and even J-B welded the muffler on. No luck. Sent it back to horizon, again. Get it back and they replaced the rear bearing again. don't know if this has fixed it yet or not. I'll keep you posted. Hopefully will put a couple of flights on it this weekend.

buzzingb

My Feedback: (2)

Some engine mounts alow excessive vibrations to loosen mufflers. Try another mount or make a bracket to help hold the muffler secure. You aren't the first to experience this. You must get it fixed or you will ruin your threads in the muffler or the head due to the vibrations.

kmtranmd

My Feedback: (71)

I agree with the bearings/vibration possibility. I have 4 Saito 180 in warbirds, but only one in a Zero keeps coming loose. I ended up just putting a safety cable on it in case it comes loose again, despite locktite with alcohol cleaning. I may have to send it in for bearings check if I get around to flying it again.

LDM

My Feedback: (15)

wow , I thought it was just me , thanks , I even use J-b weld

PLANE JIM

My Feedback: (109)

It sounds like after all that -there may be other vibrations going on with your bird-prop out of balance, a mount that may not be rigid enough or something along these lines causing the muffler to work loose since it located on the outermost point that a harmonic may travel -just my thoughts

ram3500-RCU

My Feedback: (221)

Another thing I have found is that aluminum mounts help this problem. The vibration is much less with a metal mount over a glass fill nylon one such as come with just about every kit or ARF these days. I think the whipping the muffler gets with soft nylon mounts stretches the threads on our aluminum mufflers and allows them to work loose.

mofosheee

My Feedback: (4)

I use a product that I obtained at work. The name is copelite and it is for hi pressure steam fittings. It smell like _)(&*&&^%^$ when uncured...........let the muffler come loose one time and you will damage threads

But I never had Saito muffler problems again

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electronutter

I had this problem with my 100 then i balanced the prop (like the instructions tell you to) and it doesn't do it any more.