Author Topic: fuel draw problems (Read 3591 times)

DanielGelinas · « **on:** July 09, 2012, 10:52:20 AM »

Hi Guys,

I'm having problems with my B40s in a ARF oriental.

I am having trouble starting two well seasoned B40 in my oriental.

the first engine started on prime and quit after a few seconds, over and over again until it finally started. This was a few weeks ago. It ran great once it started.

This weekend, I never managed to get it fully started. It seems to run on the prime only.

So, I pulled the engine out and changed for another B40 I have. Also checked and cleaned the fuel filter.

Same problem... engine seems to start on the prime only. I did manage to get it running for approximately 15-20 seconds on a very very rich setting. Tried to change the needle setting while it was running. No change. Engine finally quits.

These two engines ran very well on the bench. So, I think the engines are fine.

The tank was pressure checked before installing in plane a few months ago. This plane has a total of 3 flights!

Is there something I may have overlooked? Tank is a 4 oz. uniflow, all plumbing forward from Brodaks.

Also noticed fuel running out of venturi when tank is full. I'm assuming this is normal for an inverted engine?

Very frustrating...

Thanks for any suggestion's!

-Daniel

kenneth cook · « **Reply #1 on:** July 09, 2012, 11:51:10 AM »

Hi Daniel, I'm sitting here with my same exact setup like yours in front of me with the tank hatch removed. Looking down on the plane the pointy wedge side of the tank is on the left. The fuel pickup is also the far left pipe. My middle pipe is the overflow pipe which is capped during flight and the cap is only removed during filling . My far right pipe is where I've hooked my muffler pressure tubing onto. I fill through the muffler pressure line or uniflow line with the overflow cap removed. This must be removed or you will instantaneously send fuel into the venturi. I fill with the nose at a slight attitude and fill slowly but continuously. I don't remove my syringe until I cap the overflow. If you want to force feed a tad bit of fuel up to the venturi you can now pressurize the uniflow pipe which will put the fuel up to the venturi. I start my Oriental upside down and not on it's gear. I generally don't have a problem with starting. Ken

DanielGelinas · « **Reply #2 on:** July 09, 2012, 12:37:10 PM »

Hi Ken,
The only difference with my setup is I'm not on muffler pressure.
I will check the tank tubing tonight, but I doubt its an issue since I already have 3 good flights on the plane with no issues (apart from starting the engine)!
I tried starting upside down also and thats when I got a 20 second very rich run.
Thanks for the tips Ken!!
-dan

DanielGelinas · « **Reply #3 on:** July 09, 2012, 03:26:08 PM »

Thanks Ty,
I'll have a few more things to check!
Regards,
-Daniel

Balsa Butcher · « **Reply #4 on:** July 09, 2012, 06:23:10 PM »

Another suggestion: Brodak 40's flood real easy. Try less prime. The fuel can get in the case and the engine will run rough and not respond to NV inputs. It's not only B-40's, I have had the same thing happen to a piped engine. The fact that it runs fine on the bench makes me think that may be the cause.

Paul Smith · « **Reply #5 on:** July 09, 2012, 06:54:30 PM »

OS 40. Worked for me.

DanielGelinas · « **Reply #6 on:** July 09, 2012, 07:48:44 PM »

Thanks Paul, I have an OS .40...runs very sweet but REAL HEAVY

Nope, I really like the B40s... light, nice run, powerful. Perfect for the oriental.
I'll certainly let you guys know when I can figure this one out.
Regards,
-Daniel

Geoff Goodworth · « **Reply #7 on:** July 10, 2012, 02:58:00 AM »

I've had the same problem with the same model but with a Fox 35. I used the recommended tank and eventually changed the vent tube connected to the tank.

I had two pieces of copper tube fixed to the fuselage side with standard silicon tubing between the fuselage side and the tank tubes. There was a slight kink in the vent tubing but I thought it was open enough to allow air through—Wrong!

I eliminated the kink and went flying.

Two engines misbehaving tells me that the problem is with the tank or the plumbing.

DanielGelinas · « **Reply #8 on:** July 10, 2012, 10:46:55 AM »

Heres some pictures of my setup, in case some of you see something obvious which I cannot.
Thanks

-Daniel

DanielGelinas · « **Reply #9 on:** July 10, 2012, 10:49:16 AM »

more pixs

Balsa Butcher · « **Reply #10 on:** July 10, 2012, 10:54:40 AM »

That set-up looks good however I recommend pressure checking the tank for pin hole leaks. I have found some on both Brodak and RSM tanks. My money is still on the over-primed/flooded theory though.

DanielGelinas · « **Reply #11 on:** July 10, 2012, 10:59:01 AM »

Thanks Pete. Looks like the setup I have is different from Ken's. In MY setup:

-Far left is the pickup tube
-Middle is the fill tube.
-Far right is the overflow tube.

This is as the brodak instructions in the ARF instruction booklet.

Does that sond right?

Thanks,

-Daniel

Balsa Butcher · « **Reply #12 on:** July 10, 2012, 11:19:12 AM »

That looks like it should work. Again, check for leaks which can be done by sealing off 2 of the tubes, attaching fuel tubing to the third, submerging the tank underwater in the kitchen sink after first removing the dishes, and blowing until your face turns red. I'm not sure this is the problem but it doesn't hurt to check.

DanielGelinas · « **Reply #13 on:** July 10, 2012, 04:27:20 PM »

Actually checked the tank before installing a month ago. All was well at the time and I only have 3 flights since.

I'll try starting upright next time.

Paul Wood · « **Reply #14 on:** July 10, 2012, 06:23:51 PM »

Daniel,

Am I confused? It looks like the NVA has been flipped. If so, the first thing I would suspect is a slight misalignment of the spray bar. Or a small leak around the spray bar. I'm sure you have checked this, but I'm going through the same issue right now trying to get the spray bar correctly aligned on an Evo .36 that I have put a ST NVA in.

Paul

DanielGelinas · « **Reply #15 on:** July 11, 2012, 08:29:09 AM »

Hi Paul,

I believe the NV is in the correct position. Maybe whats confusing in the picture is that the plane is upside down.

Thanks,

-Daniel

Steve Helmick · « **Reply #16 on:** July 11, 2012, 12:28:30 PM »

Ty might have something there. Reduced pumping efficiency, at the very least. I'd expect needling inconsistency, reduced power, etc.

Steve

kenneth cook · « **Reply #17 on:** July 11, 2012, 01:26:34 PM »

Since your on the leak check, I highly suggest using a 5oz syringe to test your tank and inflate it like your going to blow it up. The solder in the tank your using is quite inferior and I've had several tubes fall out. I would also submerge the engine into water just covering the backplate and check for leaks there as well. Ken

Paul Wood · « **Reply #18 on:** July 11, 2012, 03:38:45 PM »

Hi Daniel,

Not to press my point, but I mentioned above that it appeared your NVA was reversed. Did you buy the engine from someone else? I have a attached a photo of my B40 that I bought new and my NVA is definitely reversed from yours. If someone swapped it before you got it, they may have either misaligned the spray bar, or as Ty mentioned, not tightened/sealed the NVA. This may have allowed a few good runs before the spray bar moved or leaked. Good luck. It is very aggravating!

Paul

RandySmith · « **Reply #19 on:** July 11, 2012, 03:52:30 PM »

Daniels is in correctly
However it will not hurt to make sure it is tight and the hole is in the right position, it is not clogged, or the orifice hole in the bar has not been broken out, or the needle damaged, and that the fuel line has no nicks or holes or splits, and that the filter is tight and has a perfect seal on the sides..gasket

Randy

RandySmith · « **Reply #20 on:** July 11, 2012, 03:55:15 PM »

Quote from: Paul Wood on July 11, 2012, 03:38:45 PM

Hi Daniel,

Not to press my point, but I mentioned above that it appeared your NVA was reversed. Did you buy the engine from someone else? I have a attached a photo of my B40 that I bought new and my NVA is definitely reversed from yours. If someone swapped it before you got it, they may have either misaligned the spray bar, or as Ty mentioned, not tightened/sealed the NVA. This may have allowed a few good runs before the spray bar moved or leaked. Good luck. It is very aggravating!

Paul

Hi Paul

Which direction do you fly?

Paul Wood · « **Reply #21 on:** July 11, 2012, 08:07:25 PM »

Randy,

I fly CCW, but this is the first inverted engine set up I've flown in about a million years. Should I reverse the NVA? Never thought about it before. Crazy, I've only been doing this for 55 years!

Thanks Randy,
Paul

RandySmith · « **Reply #22 on:** July 11, 2012, 08:40:45 PM »

Quote from: Paul Wood on July 11, 2012, 08:07:25 PM

Randy,

I fly CCW, but this is the first inverted engine set up I've flown in about a million years. Should I reverse the NVA? Never thought about it before. Crazy, I've only been doing this for 55 years!

Thanks Randy,
Paul

Yep you should move yours to the other side
That setup would work on a profile or upright, sometimes not good inverted
Regards
Randy

DanielGelinas · « **Reply #23 on:** July 12, 2012, 10:41:47 AM »

I have some crap trap filters coming in soon so I,ll give that a try.

BTW, do you guys plug the overflow on the uniflow setup before starting the engine or after it is started? Or does this make any difference. I always pug it up after adding fuel and before starting the engine.

Thanks,

-Daniel

RandySmith · « **Reply #24 on:** July 12, 2012, 11:47:00 AM »

Quote from: DanielGelinas on July 12, 2012, 10:41:47 AM

I have some crap trap filters coming in soon so I,ll give that a try.

BTW, do you guys plug the overflow on the uniflow setup before starting the engine or after it is started? Or does this make any difference. I always pug it up after adding fuel and before starting the engine.

Thanks,

-Daniel

Cap off the overflow, the uniflow tube stays open

Steve Helmick · « **Reply #25 on:** July 12, 2012, 03:48:43 PM »

I had forgotten that it was a B.40. The Double Star (maker of B.40's) has made lots of spraybars with burrs on the spray hole. Put in a Randy Aero NV Assy. and eliminate that likelyhood.

Steve

Paul Allen · « **Reply #26 on:** July 12, 2012, 03:56:59 PM »

Daniel
When you say prime, is that from an external source ( down the venturi or pulled through from the tank with finger over
the venturi) ?
I seem to remember in the early B40 that the needle valve would give you a false feeling for the needle being fully closed.
Paul

DanielGelinas · « **Reply #27 on:** July 16, 2012, 02:13:17 PM »

Hi Paul,

Sorry for not responding earlier. I was away for a few days without computer access.

Prime meaning a finger over the venturi. I will replace the N/V for a Randy Smith N/V. I hope this will help.

Thanks,

-d

Bill Adair · « **Reply #28 on:** July 18, 2012, 05:08:28 PM »

Dan,

You mentioned that you cleaned the fuel filter, so the first thing I would do is remove it, and run a single length of fuel line in it's place. Those screw jointed filters can leak at the joint, and will suck air instead of fuel.

Bill

DanielGelinas · « **Reply #29 on:** July 22, 2012, 07:58:19 PM »

Bill, thanks for the suggestion. I actually changed the filter for a crap trap. Also checked the lines to see if anything was restricting in the lines. Finally, also added a PA style R. Smith needle valve.

The engine still only ran on the prime but finally got it started. As soon as I turned the nose up, the engine wants to quite. By the time i does quit, the engine is hot enough it won't start again until it is cooled down.

Next step I'm going to try my OS LA .40. If I get the same problems I will know for sure its the plumbing or tank...

Thanks,

-Dan

DanielGelinas · « **Reply #30 on:** August 08, 2012, 07:26:56 PM »

Well, here's a report on my problems with the B40 and the ARF oriental

Changed the B40 for my OS max 35s and everything works great. Just had 3 flights tonight and am amazed at how well these little engines go. Doesn't pull enough for the Oriental, but still was able co confirm the problems were the two B40's i had... or most likely my lack of understanding of how to start one... and keep it running.

I guess the max35s is just way more user friendly.

-Daniel

Chris Wilson · « **Reply #31 on:** August 08, 2012, 09:30:53 PM »

Sounds like a combination of too cold a plug and some flooding when inverted.

What grade plug are you using? And is it in good condition?

Anyway swap it out for a plug that is known to work and go from there.

Dennis Toth · « **Reply #32 on:** August 05, 2013, 09:23:43 AM »

Daniel,
You never said if you solved the problem with the B40's? If you still have the problem I would suggest putting it back on the test stand just the way it is and doing some tests. First, take the plug out and slowly turn the motor through a complete turn. There should be a slight pinch near the top of the stroke, if it sticks really tight you need more break-in time or you need to send it back to Brodak. If all is ok, check the condition of the plug, look for crude or metal specs, plug it into the glow driver and make sure it glows fairly bright.

If ok, hook up the motor and try a test run. Set needle 3/4 turn open from were you had it before. Be careful on how much you pull into the motor to prime, two pulls should do it. Flip several times forward and backward, connect glow driver and flip back against compression. If it runs only off the prime, open the needle 1/2 turn and try again. If it continuous to just run off the prime, remove the NVA, take the needle out and run a thin piece of copper wire through the fuel end then flush out with thinner. Put the NVA back into the engine with the hole positioned to point straight down toward the crankshaft. This is a good starting position that is known to work. Put it back on the block and test again. If after all this it still does not run at least rich 4 cycle send it back to Brodak and let them check it.

Best, DennisT

DanielGelinas · « **Reply #33 on:** August 13, 2013, 07:31:03 PM »

Hi Dennis,
The problem with the B40 was the user. I needed to figure out à starting procedure. Now it starts one or two flips.
Thanks,
Dan