ttomcat50

My Feedback: (2)

Little help. I have a tt pro 46 bb that's about one year old and has had about a galon of fuel through it since break in. I spent plenty of time doing a thorough break in and the engine ran great for the first year. Then, during a flight, I lost power. The engine didn't quit, but would bogg down when applying full throttle. I have it on a bench now and it does the same thing. It starts right up, runs up fine, then after a minute or less, I have to back off the throttle to keep it from dying. I can sort of gun it, intermittently to get it back up to speed but it will still only run wide open for several seconds. I haven't taken anything apart, but the crank shaft turns very smoothly and the glow plug has been replaced. Mixture seems to be right. Any ideas?

Thanks,
Tommy

XJet

We need some more information:

1. what prop are you using?

2. what fuel are you using?

3. what glowplug are you using?

4. when it starts to bog -- can you richen it to a 4-stroke setting on the main needlevalve?

5. have you tried flushing the carby to blow out any possible muck in the needle?

Flyboy Dave

My Feedback: (21)

....remove the head and see what shape the engine is in. Is there a mechanical problem
with the top end ?

FBD.

theradioflyer

I have 3 of these motors and all run flawlessly.... except for one time. I switched my fuel and it ran perfectly again. How old is your fuel and where do you store it? Do you keep a cap on it or do you have it hooked to a fuel pump system on a field box. I found that moister had crept in and junked my fuel, my engines reacted much like you described.

I hope this helps, one of my very tired 6 yr old 46 pro still runs strong!

God Bless,

Jay

ttomcat50

My Feedback: (2)

Ok, here's some more info on this:

Prop: APC 11x7

Fuel: Cool Power synthetic 15% nitro

Plug: was using OS (don't remember which one), but now using a Tower Power (medium length/medium heat). This plug is brand new and I pulled after a couple of attempts to get it running right (probably 15 min total run time) and one side of it is beginning to show some residue. I've never pulled a plug after such short use, so I don't know what they are supposed to look like that soon.

I have adjusted the mixture to see if I could get it to run correctly, but didn't try to get it to "4-stroke". What might that do for me?

I've filled the carb with Mrvl Mstry oil and hand cycled it through, but that's it. Did this about 3 or four carbs full.

I do keep the fuel in the garage and sealed with the little red insert, in the bottle and out of the sun while at the field. I Don't let it get hot and have never seen the droplets form in my own bottle like I have others at the field. I'm on a brand new bottle right now.

I've never had engine problems. I've been at this for about 10 years and my engines have been the Super Tigre 40, OS 46AX, 2 each Evolution 46NT, and the latest is my Thunder Tiger we're discussing. All have/do perform well and this is my first issue with any of them. I've maintained them pretty much the same, using care and keeping them clean, not running too rich/lean, etc. I have not taken anything off, but I'll remove the head and take a look. I'm mechanically inclined, but never had to do it work on any of the model engines, so was sort of hesitant.

If anyone thinks of anything else to check/try, let me know. I appreciate the responses and I'll let you know what I see when I pull the head.

Thanks,
Tommy

MrMotor

Check the rear cover bolts to see if they are loose.

YUKONFLYR

ttomcat50 - Does your engine still have compression when it is hot? What is the residue on the glow plug?

I would be taking it apart for an inspection, check the liner and bearings. If the bearing is throwing metal it can kill the plug in short order.

Also on your Cool power fuel[:@] I believe that your TT pro 46 is ABN constriction and that fuel, If its the green stuff, is not recommended for your engine by the fuel manufacturer Morgans and it should be printed on the fuel jug.

If it is green.......do a search for "Cruel power" and read some of the threads...........

Something is going on with that engine and heat when it warms up. As a kid I had a Yamaha 100 enduro that did just that, ran great when cold and when it warmed up, would not maintain full throttle and bogged down. It ended up being worn out! I replaced the top end and it was like a new.

Hope this helps

Let us know how you make out.

Richard

theradioflyer

Another thought. While revving it up on the ground with a full tank, check if you can see air bubbles in the line. The slightest slit in fuel line can create problems. Also a little thing I've done sense I stated flying ( Dad's tip ) I put a 3/16 piece of fuel tubing on the needle valve and then install it sealing the needle and carb.

Good-Luck[]

ttomcat50

My Feedback: (2)

Thanks for all the help! I'm going to go over everything and see what I find. I'm going to be out of town through the weekend, so I'll post again early next week.

Take care,
Tommy

wcmorrison

My Feedback: (2)

Also check the low speed adjustment. Sometimes the 0-Ring gives up the ghost and lets the adjustment move about. Put a new 0-ring on it and fixed mine.

Cheers,

Chip

Cyclic Hardover

My Feedback: (3)

This description alone is classic of an overheated engine. What caused it? Tuning? Airleak?

DarZeelon

Tommy,


Don't use CruelPower in any tapered-bore engine. The Morgan Fuels Omega™ page says this [link=http://www.morganfuel.com/omega_main.htm]right here[/link].

Also, please read all the way through [link=http://www.rcuniverse.com/forum/m_7334104/tm.htm]this thread[/link] and also [link=http://www.rcuniverse.com/forum/m_7319973/tm.htm]this one[/link], to see why CP should not be run in engines with ball bearings either.

No knowledgeable person here (or anywhere...) would recommend it for bronze-bushed, plain-bearing engines, or for lapped meehanite-steel engines either...

I am not sure CP is at all worthy of the title 'glow fuel', since its only apparent job is to keep your plane cleaner.


Omega™ is another story and a pretty good fuel from Morgan.

speedster 1919

My Feedback: (3)

The 11x7 prop is alittle too much for a 46. The 11x7 is a 61 size prop. A 10x6 or 11x5 is a good choice. Put a little castor oil in your cruel power fuel. the tower glow plug should be fine.