Webra 1.45 problem

[Keith Black]

Webra 1.45 problemFirst thing I would do is to get a higher pitched prop, I don't think the 17x2 has quite enough bite ;-)

Seriously though, have you ever adjusted the pump pressure? I've now had four different Webra or Bully 1.45 engines and all have had to have the pump pressure reduced (turning the pump screw counter-clockwise) to varying degrees to run properly.

Questions:
Does the engine have trouble idling at 1900-2000 rpm? 
Does it profuesly spit fuel out the carb and pipe? 
Is it blowing a LOT of smoke when it runs?
When it dies does it cough a time or two and blow out a few puffs of smoke?

If the answer to three or more of these is yes then I would try the following:

(NOTE: The following assumes you have already bench run the engine through at least 1/2 gallon starting extremely rich then varying the needle settings and throttle speeds.)

1. Reduce the pump pressure 1/2 to 3/4 turn from the factory setting.
2. Use an OS Type-F plug.
3. Run a 17x10N prop (at least until the engine is broken in well, that's what I always use).
4. Adjust the low end needle so it will idle at around 2K for about 30 seconds then accelerate to full throttle without coughing on the run up. 
5. Adjust the high end idle so it will spin up around 8300 rpm (with the 17x10 and greves pipe set per Piedmonts specs) but is still blowing a good amount of smoke. I make sure mine always blows smoke even after break-in, but even more so during the first several gallons of fuel.

When the high end is pretty rich, as you want it for flight break-in, you may find it has trouble going from the mid-range to high throttle without coughing, sputtering and sometimes even dying. Two of my engines have had this problem, two haven't. It's possible that the two that had this problem were left richer during the break-in flights. The two that had this trouble would go from idle to full throttle just fine but would have trouble if run at mid range for a while then pushed to full throttle. I believe this was because I had them so rich, but my goal was to break them in without damaging the engine. If you have this trouble then for your first gallon of flight break-in just avoid the mid-range and fly primarily at idle and full throttle. That may sound screwy but it worked for me. After you've got a couple of gallons of fuel through start slowly leaning out the high end needle so the mid-range transition improves. As the engine breaks in and you get closer to the proper high end setting the mid-range will improve and eventually should be very smooth and reliable. Note, as you adjust the high end you should also re-adjust the low end as described in step #4 above.

Expect the bearings to need replacing by flight 40 or perhaps even earlier. On my most recent engine by the time I got it broken in really well I only had about 15 or so flights until I needed to change the bearings. However, after the bearing change it ran better than ever being broken in and having new bearings .

Best of luck,
Keith Black


  ----- Original Message ----- 
  From: Gordon Anderson 
  To: discussion at nsrca.org 
  Sent: Saturday, July 24, 2004 3:37 PM
  Subject: Webra 1.45 problem


  I'm having a problem with my Webra 1.45 and I hope someone can help me out. I have a new Hydeout (thanks to the guys that gave me the control throw advice!)  with a new Webra 1.45. Below are the details on the motor setup:

  Prop: APC 17x2 
  Fuel: Magnum #1 
  Plug: OS #8 
  Pipe: Greves 
  Mount: Hyde type soft mount and nose ring 
  Tank: Tetra 20oz, on CG of model 
  I have about 2/3 of a gallon of fuel run through the motor, this Webra uses the regular carb with the high speed and low speed needles.

  The problem is the motor dies when I roll from inverted to upright. This happens mostly after I have been at idle for a while. I'm flying the advanced routine and it dies during the roll out on the bunt and the bottom of the double I even the slow roll. I have never made it more than about 3 minutes into a flight.

  It seems to run fine on the down lines at idle, like in the stall turns and the outside square loop. 
  When it dies it sounds like someone pulled the fuel line off the engine, it just un winds. We tried leaning the low speed needle, replaced the tank internal fuel line to the clunk.

  Any advice? 

  --Gordon 
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