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Fitz Fuel, does it work? Empty

Fitz Fuel, does it work?

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Wanted Fitz Fuel, does it work?

Post  smcmanus Thu Nov 11, 2021 9:45 am

I'm a newby to this forum. I searched the forum, and read all the won't run topics. I have some 50 y/o cox toys from my misspent youth that I'm trying to revive.
Everything is clean, I have good glow and fuel flow. There are no nearby sources so I ordered a couple of quarts of Fitz Furl 24% nitro 1/2a fuel. I'm wondering after many attempts if this is a potential problem. The only other fuel I have on hand is 30 y/o cox super which I find suspect.
Any advice appreciated.
Thanks
Steve
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Wanted Re: Fitz Fuel, does it work?

Post  EXModelEngines Thu Nov 11, 2021 12:10 pm

Hi Steve,

Fitz does a great job with his fuel and you will find it is one of the best on the market today for 1/2A flying. He makes a bunch of different mixes, all of which will work well, including the 24% you mentioned you purchased.

What seems to be the issue with the engine? If they have been sitting all of this time, even if put away in good shape, gaskets can deteriorate over time and congealed oils can become an issue with fuel draw.

Best Regards, Matt
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Wanted Re: Fitz Fuel, does it work?

Post  smcmanus Thu Nov 11, 2021 1:15 pm

Other than a pop or 2, I get nothing. Mostly nothing. This viscosity of this fuel seems thicker than I remember, almost like motor oil.
I disassembled and cleaned everything including the reed valve and the mixer body. I'm trying to start a PT-19 and Dune Buggy.
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Wanted Re: Fitz Fuel, does it work?

Post  Yabby Thu Nov 11, 2021 3:43 pm

As Matt suggested the Fitz fuel is not likely the problem. When you disassembled the engines did you put new gaskets in the engine? What sort of engine is it? If you know you have good fuel flow and being a reed engine to get good fuel flow you need air flow. Do you know the reed is good and not leaking? I would replace the reed also and the crankcase gasket. Empty the tank, close the needle and prime the engine through the exhaust ports. The engine should run for a bit on the prime. If it doesnt do that, then I would go a new glow plug and definitely a new head gasket(s) with it. Also check its not leaking between the glow head and the cylinder. with fuel in the engine cylinder, if you turn the engine over very slowly, if it is leaking between the cylinder and the glow plug, you will see very small bubbles appear and grow down where the cylinder top is and the glow plug bottom part.

No fuel in tank, needle closed. good plug fitted and sealing with good gaskets including crank case gasket, good supply to the plug, good fuel primed into the ports, the engine should run. If it doesnt its a mechanical problem and you will need to look at piston, conrod, crank pin, cylinder bore, piston cylinder fit, piston fit to the conrod. Is the piston travelling all the way to the top of the bore? past it, below it? Are there scratches/grooves/damage to piston/bore? really badly leaking crank case gasket will cause problems as no crankcase pressure means fuel doesnt get pushed up the ports to the top to be burnt.

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Wanted Re: Fitz Fuel, does it work?

Post  layback209 Thu Nov 11, 2021 4:55 pm

Welcome, glad to hear your trying to get some of these little rippers going again. Could I inquire on your glow igniter set up? Personally I've experienced much starting pains when element was not being fed enough current.

If your getting pops you almost there,. Keep at it. The only other item I can think of is maybe a stuck Reed Valve or a major air leak.
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Wanted Re: Fitz Fuel, does it work?

Post  EXModelEngines Fri Nov 12, 2021 8:24 am

@smcmanus wrote:Other than a pop or 2, I get nothing.  Mostly nothing.  This viscosity of this fuel seems thicker than I remember, almost like motor oil.  
I disassembled and cleaned everything including the reed valve and the mixer body.  I'm trying to start a PT-19 and Dune Buggy.

Sounds like an issue with fuel draw or a rather large leak. What type of engines are these (i.e. do they have integrated fuel tanks with metal backplates)? The Dune Buggy typically does and the early PT-19 airplanes do as well until they switched to a "Product" style engine with the horseshoe backplate and external fuel tank which was essentially part of the PT-19 fuselage. I'd probably point to the spraybar as the next item to look at. If they sit for a long time congealed fuel has a tendency to clog up the small hole.

As an aside, the fuel shouldn't be the viscosity of motor oil.
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Wanted Re: Fitz Fuel, does it work?

Post  smcmanus Fri Nov 12, 2021 2:41 pm

"Could I inquire on your glow igniter set up? Personally I've experienced much starting pains when element was not being fed enough current."

Good point. I was using 2 D cells and original Cox clip. New batteries and the voltage dropped to 0.7 volt when connected to the glow plug. So I took one of the cox clips apart and found tiny wire, maybe 22 ga. which was barely crimped to the clips. I soldered some 14 ga. wire directly to the clips and now I'm getting over 1 volt when connected and a lot more sizzle. Will try to start it again.

The PT-19 has the fuselage mounted tank. The buggy has the integral engine tank.

Thanks
Steve


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Wanted Re: Fitz Fuel, does it work?

Post  layback209 Fri Nov 12, 2021 8:04 pm

@smcmanus wrote:  "Could I inquire on your glow igniter set up?  Personally I've experienced much starting pains when element was not being fed enough current."

Good point.  I was using 2 D cells and original Cox clip.  New batteries and the voltage dropped to 0.7 volt when connected to the glow plug.  So I took one of the cox clips apart and found tiny wire, maybe 22 ga. which was barely crimped to the clips.  I soldered some 14 ga. wire directly to the clips and now I'm getting over 1 volt when connected and a lot more sizzle.  Will try to start it again.

The PT-19 has the fuselage mounted tank.  The buggy has the integral engine tank.

Thanks
Steve



Awesome, that sounds like it's going to do the trick. Good call on swapping out the wires and redoing the crimps. I found the same thing. Here's a few of the igniters I use. Of all of them honestly the old old school nicad or nimh sub-c cells seem to work the best for me.

The top is 4 D 1.5v in series. That typically lasted me a summer. I squashed a chunk of copper pipe flat, filed the edges to make the contact strips. Electric chicken tape to hold it all together.

The right one is a step down voltage regulator I have set at 1.5v out. 24v in ftom a drill battery I have (drill let the smoke but but battery is good). It works good to. I also use the drill battery for nitro heater and starter.

The bottom ones are the standard rc style. The blue has a 3000mah nimhi 1.2v sub c cell. Very good service from it. The red dubro I'd a nicad 1.2v sub c cell. Can start cox with them if you hold it on or use alligator clips.

Fitz Fuel, does it work? 20211110
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Wanted Re: Fitz Fuel, does it work?

Post  smcmanus Sat Nov 13, 2021 5:29 am

Newly energized, I hooked up my rewired glow clip and got immediate fire.  Now I can get it to run on prime for a nice BBBRRRRAAP! and sometimes up to a few seconds.  A couple of tries I got one pop and the spinner spun off.
This is on the PT-19.  The mixer has been cleaned with Gumout.  Not sure what I'm missing.  Don't remember how it worked 50 years ago.
Thanks
Steve
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Wanted Re: Fitz Fuel, does it work?

Post  smcmanus Tue Nov 16, 2021 2:58 pm

I replaced the fuel hose and also put a bit of hose on the needle valve and mixer body as I saw elsewhere in the forum.
Several fits and starts. Finally opened up the needle 5 whole turns and bingo, IT RUNS! I ran 2 tanks of fuel through it. 1st time it ran in 50 years.
Thanks for the help.
Steve
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Wanted Re: Fitz Fuel, does it work?

Post  layback209 Tue Nov 16, 2021 3:06 pm

@smcmanus wrote:I replaced the fuel hose and also put a bit of hose on the needle valve and mixer body as I saw elsewhere in the forum.
Several fits and starts.  Finally opened up the needle 5 whole turns and bingo, IT RUNS!  I ran 2 tanks of fuel through it.  1st time it ran in 50 years.
Thanks for the help.
Steve

Awesome! Nice work.
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