MOJO65-9or10

Here is one aspect that no one has mentioned yet and that is that the tower series of engines are all set up in "deals" to get the new, first timer in the air. With that in mind there are more newbies trying to get their FIRST engine running right and really are chasing there tails since they have no experience. I fell into that catagory and the tower 46 was my first RC engine and I did not have good luck with it at all. With that said and now with my greater experience I am thinking about adding one to my fleet of OS 40 sized stuff since I keep reading that they are strong once running right and parts are pretty cheap. I do feel that they are not tops in quality control but you usually get what ya pay for. I think a majority of issues come from the carbs as with most engines.

I had an Magnum 52 2-stroke that I couldn't get to run consistently when stock. Well it ended up under my bench for about a year and I ran and LOVED a 46ax til it was wore out. I then came across the magnum under the bench and tried to run it with the 46ax carb and now it IS my strongest running "40 sized" engine. It was pretty cool to take it out for the first time with the new carb since it ran just like my ax did only a good bit stronger. I am not suggesting anything to anyone but if you have problems with one engine and you have a carb from an older or worn out 46 go ahead and give it a try, I am glad I did.

As a side note my magnum 52 with ax carb out spins my new OS 55 by about 200 RPM's on a 12 x 4 APC. (same prop, muffler, fuel, day) I have also had my OS55 quite twice on me for no apparent reason, although there is diffently one. Twice while hovering and a tad on the rich side. I think it may viberate more and be drawing air into the pick-up but don't really know. What I do know is that I have an airplane to fix now.

To often people what to know what is the best engine to get and they get an answer of XX brand is better than XX, but the best engine on the market is one that is reliable over all else. You will see that OS, TT, Mangnum 4-strokes, saito, YS for experienced tuners, irving, tower 75 not 46, all have great reps and that makes them great choices for the first time flyer. If an engine just needs this or that to run great don't get one as a first time RC engine or you will be unhappy. Happiness come from flying NOT tuning.

I am sure I missed plenty of engines in my short list,
Dave

opjose

As Flyboy Dave said...

I used a rubberized clamp to push the carb against the engine body before I tighten them down.

This has worked very well for me.

opjose

MOJO65-9or10:

Tighten down the carb well and DO NOT adjust the needles and I've found that the TH .75's and .46's shipped out nowadays will start up right out of the box. After that standard break-in and small adjustments are all that is needed.... remembering that the engines need about a gallon of fuel to come into their own.

Whereas the first TH .46 one I received a couple of years ago was horrific at first.

Some thing has changed...

misterpanda

Another good feature of the TH 75 is the second "O" ring embedded insde the hole that receives the carburettor, providing a total seal.

Misterpanda

prepressguy

It's unlikely that I will ever buy another one. I have had a few good flights with the Tower but mostly it just doesn't run for more than a couple of minutes then dies suddenly.

The engine is well broken in and I have had several perfect flights. I'm running an 11/5 prop on it.

It seems to run better if I leave the glow starter on. I haven't had a chance to really go through and check for leaks.

We have checked for debris in the line, fuel foaming, needle settings both low and high, muffler leaks. muffler extension, running a hotter plug and two gaskets on the plug with little results.

It doesn't do any better with an outboard tank and doesn't really idle slow very well

Things I haven't tried yet: smaller prop, RTVing the carb and back plate, higher nitro fuel (I'm using 10%)

The engine starts easily but is very slow to change from idle to hi speed. It takes about 15-30 seconds with drops in the rpm and coughing if I throw the throttle to high. Slowly moving the throttle does work better. When it gets up to speed it's just as likely to instantly cut out.

Any possible solutions?

opjose

If it "dies suddenly" then it is either not tuned properly or there is a problem with your fuel system.

The latter is most likely.

A sure indication of an overly rich condition or the use of an improper heat plug.

When the engine is properly tuned there should be NO change what-so-ever in the RPM's no matter the attitude, when the glow plug ignitor is removed.

The ignitor helps the engine deal with too much fuel.

That should be done with ANY engine especially after it's first run or two. The heat causes things to loosen up, etc.


The T.H. Engines do not need a hotter plug nor two gaskets ( which LOWERS compression a bit ). They DO use "longer" plugs however. I use the Fox "Miracle" plugs with great results.

Poor idling tends to indicate inproper tuning or a fuel system problem.... assuming you haven't at any point tightened down the low speed needle to the point of damaging the needle itself.

Yup not tuned or fuel system problems and pressurization...

Re: "Starts easily"

You may have the low end opened a bit too far to compensate for lack of fuel pressurization or poor flow from the tank.

Do this...

Start the engine, and set it to a low idle.

Let it run for 2+ minutes. Does it slow down over time or stay the same.

If it slows down it is too rich. Adjust. Once it stops slowing down, perform a pinch test at idle. HOLD the line pinched. How long does the engine continue to run? 2+ seconds is OK ( provided it does not slow down ). If it cuts out immediately or in under 2 seconds it's too lean.

Once you get this fixed... advance the throttle to the point that the engine starts sounding a bit rough. Now adjust the high speed needle for MAX RPM's and back off a bit. Can you now advance beyond the point it cut off?

If so, now adjust the high speed, and perform the pinch test.

A quick pinch SHOULD result in an immediate increase in speed, but the engine should continue to function.

If you find that you've had to adjust the high end quite a bit, go back and adjust the low end.


If none of the above seems to work, check your fuel system.

It is likely that there is too much resitriction to fuel flow, or lack of proper pressure.

The muffler produces quite a bit of pressure.

One thing that can happen, is that the pressure nipple on the muffler can clog with the debris that is ejected from a new engine.

Most newbies fail to check the pressure nipple to see if it is clear.

Put a clean hose on it and blow through the hole. You should get almost no resistance.


Do the same test with the carb, with the throttle wide open. You should have no problem blowing air into the carb via the tubing.

Test the remote needle too. It SHOULD produce some resistance.

Flyboy Dave

My Feedback: (21)

....the carb must be down tight.

....if you have an air leak under the carb, it wil never, never, never run right. It will
be impossible to tune (even if you can tune a carburator) and will die and run
erratically in flight.

FBD.