ok, before I send this back to Jetcat, I thought I might ask the pro's here. Tonight I wnated to fire up my P-120 and just make sure everything was working good before I head out to the field. I flew it about 4 maybe 5 months ago, long hard winter.


Problem I am having is the propane line inside the can must be 80% blocked. I did a bypass around the propane valve and fed the propane direct into the 120. I can hear it spitting and sputtering, not a clean spray. SO, other then sending it back, is there anything I can do that might free up the blockage? I did try to blow compressed air in the line, but no luck.

Mark

Mark, in all my years I have never heard of or seen a blocked propane nozzle in a jetcat.

Is there a reason you bypassed the valve? Just fill the tank up and do a propane valve test to check the entire start gas system. You should hear a solid pulse of gas entering the chamber. Check this and let us know what it does.

John, after several attempts to start the turbine, I decided to try a few things for process of elimination, I was using the green bottles for the propane. would not start and bottles were low on fuel. I then switched back to powermax, same problem. then I plugged the powermax direct to the turbine this bypassing the propane valve. same problem.

so I know the valve is ok, propane does enter the turbine, but at a low rate, almost like it has a pinched line, kind of what a garden hose dose when pinched in half. it does fire on propane but barely. when I disconnected the propane line from the turbine, there is plenty of back pressure in the line.

nothing was disconnected or removed during the winter months.

if I was to remove the front cover would I be able to see the line?


Mark

Hi Mark,
Waiting for the first nice weekend to head down to the field. Hope you get the problem worked out soon.......

remove the front cover (the purple one)

You can see the line

BRG

Are you sure this isn't a glow plug issue? I would try a new one. <div>
</div><div>Arnaud</div>

A burner test will eliminate that.

it's not a plug issue, the line is 80% blocked....................

gonna pull the front cover off and see. out of 8 years of flying turbines, this is a first...

My suggestion, start from scratch. Make sure the system is full of propane/butane, assuming you are using powermax or a substitute propane/butane source. I'm sure you know that you should see the propane flowing in the fill line and stop filling when the bubbles slow to a near stop. My P-70 will not start reliably if I am low on powermax. Once you are assured that the system is full, then do a start. Could it simply be a low quantity/pressure in the powermax supply can? Another thing I've learned, with the dwindling supply of powermax, is that the other style propane/butane containers have to be turned upside down to get liquid into the onboard tank where with Powermax, the container is held upright.

Nothing you can see with the front cover off. Propane goes straight into the manifold. There are no propane lines under the cover.

So you have not tried a gas valve test using the GSU.

Are you using a 3 - 4mm festo to reduce the line down or the included brass piece that comes with the engine. We changes this years ago, just trying to find out what era engine you have.

Where are you hooking propane up to do a direct feed to the engine?

It could be possible the oring is rolled inside the 3 - 3mm festo at the engine. That is about it.

FIXED...................... doing a Happy dance.

What was the fix?

ok, here is what the problem was and how I fixed it.

The propane line feeding the manifold was blocked. After I removed the P-120 from the Boomer, I removed the front cover, checked the double festo fittings on the propane line and they were clear. I sprayed propane into the kero line, no problem. I sprayed a little, and I mean little cleaner into the propane side, thinking maybe fuel jelled up and blocked the line. I let it sit for a minute then I tried to spray Powermax through it. nothing again. After scratching my head for a minute, I connected some clear tubing to the hard line on the propane feed and my hand held vacuum pump. I began to squeeze the pump and watched the gage climb. About 5 seconds later, the gage dropped right to zero. I then connected my Powermax bottle and the line was clear and the propane flowed like it should.

tomorrow after work, I will put it back into the Boomer and fire it up and see how it starts...............

Mark

So you put vacuum on the line and pulled something out? Amazing.

Were you running a filter on the gas line downstream of the shutoff valve?

great troubleshooting BTW

Matt. NO I do not have a filter on the propane line, But I will very soon. just have to order one. I dont know what made me think of the vacuum pump, but hey, It worked...........



Mark

Yes when we used the green coleman cans we saw significant crud coming out, less I think with Powermax. Of course you can get debri shedding out of the shutoff valve as well.

well, I have used Powermax for years and NEVER a problem, I just started using the green bottles, but I still have 5 cans of Powermax and I think I will stick with that for now.


Mark

well, tonight as planned, I put the Boomer all back together, charged the ecu battery, so, with fuel in the tank, propane connected, fire extinguisher near by, I made my first attempt to start the P-120 after clearing the blocked line.

first start it popped right away. running on propane, spooling up kero kicked in, just waiting for the green light to come on and she quit.............................................. .

I had the GSU plugged in, first glance ecu show low voltage, ECU battery died. I will get a new one tomorrow and I might as well change the two flight packs at the same time.

But all is good and we are ready for the season upon us.

Mark