do you guys think that the plastic throttle rod that goes from the servo to the carb will melt if it touches the muffler? so far that's the only way I figured out how to install it.

change it to music wire, the odds are good that won't melt.

depends what sort of plastic

It's the stock hardware that came with the kit (Mayhem 3D). I don't know what it is.

Yes it will stretch and you'll never be able to get the idle set use a flex cable

If you can space it away even 1/8 inch it should be fine. For a spacer use a small ceramic piece from an old electric heater!

aaaaaaa.....who has an old ceramic heater anymore

I'm no plastics expert, but my experience has been that just about any plastic will melt in contact with a hot muffler. A little airspace will save it, but contact will melt it. If not airspace, find something that can be fit in somehow to provide insulation.

If you go for bare metal, be absolutely sure you have clearance between pushrod and muffler through the entire range of throttle up & down. I had terrible interference once from a metal pushrod inside a plastic guide tube. The plastic would touch up against the muffler, finally melted through, and the metal pushrod would scrape against the muffler. Every time I'd touch the throttle, the plane would throw a fit.

I have learned to be very careful in routing my throttle pushrod. I fit a piece of wire just long enough to run from throttle arm to firewall, clevis it to the arm, move it around with the engine mounted to see just where I want the pushrod to come through the firewall. With some mufflers, plus tank clearance to watch out for, the open spot can be very small.

im curious as to what engine has the cable route so close to the muffler?

can you change the adjustment hole on the throttle arm and get it away just a little?

or move your routing hole in the firewall a little?

good luck

On Moki engines the control rod comes close to the exhaust port. I always use a metal rod, also you can use a ball link clevis on the throttle arm to space the rod away from the muffler. You can also angle it slightly to give you some more space. I would not use plastic in this case. In fact I would try to avoid plastic altogether for control rods. If you need the electrical isolation (gasser) use plastic clevises or ball link clevises.

I have an OS .91 and the carb is at the front of the engine. The rod has to travel from the firewall between the engine and the muffler (which is little space) to get to the front (by the prop)

Here is some pics to show you what I've got. As you can see there is not much to work with. There isn't any straight line between the firewall and carb arm. Any suggestions now that you see the pics?

P.S. What's music wire? Where do I get it?

Get a wire that in diameter it does not bind in the guide tube and then make 2 bends to avoid contact with the muffler. The throttle arm takes very little force to move so the wire normally won't flex. Other wise you need to reposition your throttle guide tube. Music wire is stiff wire/rod normally stocked at a hobby shop.

music wire also called piano wire as it was used in pianos

Strulag, as I look at the photo on the left, I see a small area in the upper right corner between the muffler and the engine mount, which is probably what I would try for re-routing the throttle pushrod. That would run the pushrod along the side of the interior of the fuselage, and should clear the tank. You don't have to have an absolutely straight line from throttle arm to throttle servo; a bowed routing, if not too severe, will work OK.

I've had installations where I ended up plugging one firewall hole and drilling another, sometimes a third or fourth to get the routing right. I've seen installations where the pushrod was routed through the plastic engine mount itself--with a hole drilled through the plastic and continuing through the firewall.

No question, this can be a tricky part of putting a plane together. I have also used delman's trick of putting an offset bend in the pushrod wire so I can come out of the firewall in one line, and with two bends offset the routing to get around one obstacle or another. I had one ARF that was so poorly laid out I needed to put in a pivot arm to drive the pushrod through the only clear spaces available, offsetting the routing by an inch and a half or so. Sometimes you have to do some radical thinking to get these buggers to work right.

Hey majortom...That picture is deceiving because I took the picture a little from the left. If you look at the one on the right you'll see that there's no room between the mount and the muffler to the left either. Even if I go that way the rod will still have to be bent and will still touch the muffler. By the way...how do you plug your holes in the firewall? I might have to do that as well. It's hard for me because I'm very new to this. I don't even understand some of the terms in people's suggestions to me. One way that might be easier is to stick something to the muffler that doesn't carry the heat over to the rod.

OK, I'm looking at the photo on the left. I'm looking at the throttle arm. Behind the throttle arm the photo shows a small area of clear firewall. That is a simple line of sight, clear of everything, clear of muffler, clear of crankcase, clear of engine mount. This little area is "around the corner" of the engine mount from where you currently have the pushrod coming out. That's the spot I would choose, just from looking at the photo.

It may be that if I had the whole thing in front of me, I might find another spot I would like better, but the spot I'm speaking of looks like it should work. Complications which are unseen in the photo, such as what's behind that spot on the other side of the firewall, might need to be dealt with. Perhaps a shifting of the fuel tank. Perhaps another hole drilled through a fuselage former. This might call for a long drill bit from the hardware store, a 12" bit perhaps. If that's what you need, buy it, because you'll use it more than once. They don't cost much.

To plug the unused hole in the firewall, just cut off a short length of 1/8" dowel, or whatever size your hole is, tap it into the hole in the firewall and hit it with a drop of CA to seal it, or cover it with a dab of 5-minute epoxy. (By the way, if your firewall is fuel-proofed with epoxy, you should sand the surface before you try to epoxy over it. Most epoxies have a wax component that comes to the surface during cure. If you try to epoxy over cured epoxy, the wax will impair the bond. So just sand it lightly and the new epoxy will bond to the old.)

I understand your frustration with what seems like it should be a simple matter. I've been there many times. Throttle pushrod routing takes imaginative thinking. Such things are never spoken of in the glowing reviews of ARFs and kits, because they're too darned tedious. Don't be fooled. All those reviewers have on more than one occasion sat helplessly and furiously cursing a model in front of them. I've had firewalls with more holes in them than swiss cheese.