I love this engine but I cannot keep the muffler on !!!! About 2 flights is all I get and then it is loose. I have tried everything, including blue thread locker, red thread locker, JB Weld, nothing works. I contacted Tower Hobbies where I purchased it from and they told me that I probably tightened to tight to start with. They said if you do that it will work loose and nothing will keep it on. They said to just snug the nut up against the muffler. I am talking about where the muffler connects to the header, not the engine. I hate to pay $63 dollars for a new muffler... I thought Tower would warrant it, but they would not. I have bought a ton of stuff off of them, but I guess that doesn't matter. It seems like Horizon has much better service after the sale.

I have a couple of these engines since they first came out. I've never had trouble with the muffler. I have four mufflers.

Why do you have 4 mufflers for 2 engines?

People over the years gave me mufflers. A couple are from Surpass I's and one is a prototype of another design that works very well on the Surpass II. Then I have the two original Surpass II mufflers. The Surpass I mufflers are a little smaller and lighter.

use the magnum muffler its cheaper and works fine. Also if you still have trouble try teflon tape, the red locktite should work okay.....

First, balance your prop. That alone might do the trick.

If it doesn't, use the old safety wire trick. Get some thin copper or steel wire, wrap it around the muffler at the pressure nipple with one wrap around the nipple. Now twist the two ends of the wire and wrap the twisted section once around the header opposite the way the muffler screws off. Finally, tie it off at the head. Now it can't unscrew without tightening the wire.

Do a Google image search for Safety Wire for pics

I would suggest you use alcohol and a old toothbrush to clean the threads on the header and inside the muffler and jamnut threads, get all the old oil, varnish and metal particles out of those threads. Put everythind back together and snug down the jamnut. Should be good to go.

The prop balancing idea is a good one also, always balance your props.

I bought a Saito 62 from a guy on here that he sold because it was breaking muffler manifolds

It came with a new manifold. I'm using it for the second year and have never even adjusted the needle valve let alone have muffler trouble.

He sent an aluminum spinner and adapter nut along with it, The 2 1/4" spinner had been forced over a prop without being cut out. I don't know if that was the problem or not?

The teflon tape is a good way to go for the moment. Balance your prop(s) with a good balancer, not the finger balancer.

Use something like Dawn's Power Dissolver to clean the threads before wrapping with the teflon tape.

I have tried everything... nothing is working. I ordered a new muffler and header. If it comes loose this time I am sending the whole engine back to hobby services.

I've had 9 of these type engines and the designs that came before them and some for 20 years and have never had a problem with the muffler coming loose.

Let me guess, you have been running the engine on a soft mount - right?


Ed Cregger

I guess I am the born loser, although we have 2 other guys in our club that have had the same problem.

To tighten them when they are hot from running sometimes helps

Teflon tape and really snug it up when it is hot, is the secret that I have used for years. I nolonger ever see problems at our field after I told my buddies about the idea too.