Pete S-RCU

I have a Simjet 1200 with what appears to be a few clogged fuel nozzles.
When it starts, I get flames on one side of the tail pipe only.
Accelerating it sounds rough and sometimes quits.
I tried pumping Seafoam through it and letting it sit.
I think it did make a difference, but it still flames out.
I have filters on my fuel can, a festo filter before the pump and one before the turbine.

Does the fuel and oil form carbon on the nozzles?
What can be used to remove the carbon if that's the cause?
The engine is five years old, but it had new bearings last year.

jetmodeller

Hi never had a problem like this in 15 years of flying turbines,has the turbine sat unused for a while?i always blow the fuel inlet on the turbine through with compressed air when laying one up for a while as the oil can block the injecter tubes,try compressed air it may help if not it may need a service,there should be no carbon on injecter tubes as they do not run that hot with cool fuel running through.

Pete S-RCU

After shut down, the residual heat could bake some residual oil on the nozzles?
Just guessing here, I blew them out with compressed air, still the same.
After the cleaning it does seem to run better, but it's not there yet.
The rough acceleration noises are gone, but it still flames out with a big puff of raw fuel, so I know it's not a commanded shut down.

Nothing to loose by trying a few things, my repair guy doesn't answer his phone.
What I'd like to do is pump some carb cleaner through it, that will remove anything.
Not sure how many other problems I'd create though?

TimD.

My Feedback: (207)

OK, here goes . If your brave enough remove the engine from the can be careful not to tear the large oring on the seperation . Take the fuel rail off of the engine . Be sure to mark where it was for replacement. Take the fuel delivery ring manifold and injectors and hook a can of propane to it. Light the injectors and see which of the flames are not burning. All of the injectors should have the same flame height. Once you have figured out which ones are not burning mark them with tape or something. Get some carb and injector cleaner for a local auto parts store. Get a can that has a spray tube. Take the can and hook up "brake line" tubing to the spray tube and the other side to the clogged injector. Spray in to the injector and keep the manifold upside down to let any debris fall out .

This will take time but they will clear out . After blowing the tubes out backwards a few times , hook it back up to the propane can and check to see if all injectors burn evenly. If not repeat a few times.

I have done this on several engines for myself and friends and saves a few dollars. Make sure when reattaching the injectors to use either stainless or inconel tie wire.

Tim

sidgates

My Feedback: (2)

There are others precautions and procedures to follow when dissassembling a turbine engine. I think if you do a search on RCU you will find the details to follow.

rcjetsaok

My Feedback: (7)

On the AMT's we just use compressed air through the fuel line to the engine. Hit it with 130-150 psi, cleans them right out !!!! It's rare that the clog, but I've done it at the field ( I had air.. air start engine ) got me all cleared out and flying..... You don't need no stink'in UPS truck !!!!!


Danno

basimpsn

My Feedback: (5)

I'M having the same problem too [&o] My engine was sitting for two year, Just re install the engine and after the fifth flight my idle and mid sound rough. The engine almost hangup on me during go around attempt. I never try the compress air before, I always remove the fuel ring and used a torch to heat the injectors until its clears up.

gunradd

My Feedback: (9)

This is the stuff I use in full scale aviation for fuel nozzels. I could not be any happier with it. It will make a fuel nozzle look brand new after using this stuff.

http://brulin.com/productdetails.aspx?pid=118&cid=48

TimD.

My Feedback: (207)

I have had to do the torch also it works on the stubborn clogs quite well.

Xairflyer

My Feedback: (1)

Need to watch with the torch you dont soften the silver solder and make it run into the fuel ring

Pete S-RCU

Thanks for the good information guys.
I talked to the Simjet repair guy last night.
He said to increase the acceleration delay, the problem is caused by the hot, humid air.
Will give that a try first.