I thought I would come back and offer a few tips on what I have learned about the Tower .46 while on the subject. Maybe someone can get some good from this. First of all it has been my experience that 80% of the Trouble with the Tower .46 is in the low needle setting. Now I didn't come to this conclusion myself. I came to this conclusion from much research like, a call to Hobby Services, reading hundreds of post, hours and hours of tuning, flying, tuning some more, flying some more, and tuning some more, plus about 10 other people messing with the thing and offering thier advise, and reading articles in RCM Mag, and engine articles in Model Aviation plus others. After sifting through all this info, and seperating the intelligent conclusions from the ones who think maybe the timing chain is bad, I have finally almost become one with my Tower .46 engine. Its like a friend in the Hospital who you want to see get well.

Now most people including myself tend to reach for the High Needle setting when the Tower engine is not running up to snuff, and pay little or no attention to the Low needle. O.K now everyone knows that the Low Needle contols idle to mid range speed. High Needle controls past mid to High Speed, but one also effects the others operation and both must be in perfect sink for the engine to perform right. Now some engines you will get away with being off a little here or there, but with the Tower .46 it must be right on all the time. Not much leeway with this engine. With this said I recommend a Tachometer.

I know there are those who claim to have the perfect ear, but I will admit here that I prefer the Tach over my ear. As I said before the Tower .46 has to be perfectly set all the time which means that I tune it each time before I take it to the field because temp, humidity, etc. effects its opperation. Here is where I start. Set the High end first. Bring the engine to full throttle, and tune the high end needle to maximum RPM on the Tach. Now at highest RPM, richen the high needle till the RPM drops back down 750rpm from max(now write what it says on your tach down on paper). Now some may say 500rpm drop is rich enogh, which it is on most other engines, but on the Tower .46 the engine leans out considerabley as the fuel levels drop in the tank. The engine will seem overly rich on the ground, but it will lean out in the air, but by dropping back the 750 rpm on the high needle you will most likely maintain a slightly rich setting in the air. At a 500 RPM drop down it will more than likely lean out beyond acceptable range, get hot, and quit in flight as Tank levels drop!

Now that you have the High Needle set to 750RPMs below maximum RPM it is time to start on the low needle. Please do these adjustments with engine off to avoid losing a finger. Start by moving the throttle till it is all the way open. Look at the brass idle bar inside the carb and turn the needle either in or out till you have a 2mm gap or about 1/8" gap between the two little brass tubes. Now this is an overly rich setting, but the engine should start. If not turn it in a few clicks until it does start. Now as I said before, the Tower .46 will lean out considerabley in the air so we are going for a slightly rich setting on the ground. On most engines you strive for a good throttle Transition, but here we want it to load up a pinch when going from idle to full throttle. When I say a pinch I do mean a pinch. So now you will turn the low idle in until you have a slightly rich Transition which is usually a slight pause(fuel sputter) when going from idle to full. Once you have done this run the engine up to full throttle again. Is the RPM the same number or within 50 RPMs of what is wrote on your paper? Remember that I said that both needles work together?

Well the goal here is to get both in sink of each other while in flight. If the number is way off then you need to set the High Needle to the setting wrote on the paper after the 750RPM reduction. Now go back to the low needle. Is the low needle slightly rich on the ground? Does it Transition a little rich? If it does then this is great! Now let the engine sit at idle for about 20 seconds. Now see if it will Transition to full without dying. Will it idle for 20 seconds, and then Transition to full without dying? If not then it is just a bit to rich and needs to be turned in till it will maintain a idle for 20 seconds without dying, but by no means run the idle to a lean setting to get it to maintain idle for 20 secs. It may be that you can only get 15 secs. This will have to do because it is better for the Plane to load up and die on the runway then to lean out and die on approach 200 ft in the air.

Now why I say 80% of the tuning is in the low idle is because you have to do alot of this by ear where with the High idle all you need to do is maintain the number you have wrote on that piece of paper. You will do the most fidgeting with the low needle to get the idle right and the Transition. Fiddling with the low may affect the high needle number by 50 RPMs either way, but this is fine because we have allowed for this by dialing back to 750RPMs. Now check you RPM at high. Is it close to the number on your Paper? If it is then this is great. Now drop to idle. Will it maintain idle for 15-20 seconds running slightly rich and Transition to full without dying? If it does then this great. Does it load up and die sometimes on the runway after the 15-20 sec idle time has expired? If it does this is normal(At least normal to me). Can you put your hand on the engine head without burning yourself after a 10-15 minute flight? Then this is great because it means the engine is getting plenty of fuel. You should be good for the day if everything is in sink, but you will find out that those settings have magically changed the next time you fly under different weather conditions. So all this will have to be repeated.

Now everything I have wrote here is just personal experience with my Tower .46 engine, and is what I do to keep it running. These steps may or may not work for your Tower .46, but I have found these steps crucial for successful flights with mine. You may decide that this sounds like a big headache, and just throw the thing in the trash. Just remember though that if you can get it running like it should, that this engine has gobs of power, and even sounds like no other. Even with the Tower Muffler on the TT .46 they don't sound the same. Also remember that I am not a professional engine guy, and it is always smart to get several opinions on something. This is just a post that I wrote to help some poor unfortunate soul who has tried everything else with there Tower engine, but may not have tried to do it the way I suggest. Do I guarentee this to work?..............Absolutely not! But if your frustrated enough you may want to give my suggestions a try, and you may get good results. Give it a try and let me know if it works or does not work for you.

Note: I run my Tower .46 with an APC 11X5 Prop, O.S#8 Plug, and 15% Cool Power fuel. Good Luck!