azalner

My Feedback: (8)

I have a DLE-30 that I took apart and cleaned after a crash last year.

After assembly, the engine ran but only at 1/2 to full throttle. The low needle had no effect so we assumed the low speed jets were clogged. Took the carb apart, cleaned it (the jets were clogged with residue), replaced all the gaskets and diaphragms.

Now the darn thing wont run at all. Watching the line from the tank to the carb, it appears there is no fuel movement when I flip the prop.

Anybody run into this before?

Al

av8tor1977

My Feedback: (6)

Sometimes when the carbs are completely dry, they don't want to pump fuel. When I rebuild a carb, I flood the interior areas with a shot of WD-40. If it was a good while ago that you were working on it, the diaphragm could be bad. A stiff diaphragm can make them not want to admit fuel. You can try priming the engine with a shot of gas and starting it. Sometimes they will then start pumping if it is just a "dry" carb. Of course all this is assuming the cleaning and re-assembly was done correctly.

AV8TOR

MetallicaJunkie

membranes and diaphragms dont last as long as they used to... ive seen it personally, and also spoke with a lawn mower repair shop tech and now its confirmed... it's the damn ethanol in the gas

captinjohn

You cannot blame the gas with ethanol completely. I sold my son-in law my 20 year old 4.2 cubic inch pro chainsaw. It has never had any rubber part changed in the carb. It runs like new and I can post a photoofa pile of wood he cut in 3 days...One heck of a lot of wood. The problem is the new rubber parts are junk compared to what they could be. This is planned that way so you buy the saw or watever cheap...and then pay for parts that they make a killing on. Junk 5 cent rubber diaphram. Shoot all dealers are that way...look how they skin the average joe just on car parts....or whatever parts. Darn crooks should be tarred and feathered !

Capt,n

RTK

My Feedback: (1)

Did you reassemble the carb correctly?? Also check the reeds and the pulse line holes to make sure they are lined up, they do run an internal pulse line right??

azalner

My Feedback: (8)

There is not much to these things. That is what makes this so frustrating. I've cleaned and re-assembled these before without issues, but you're right the first thing I did was remove it to see if I made an error in assembly. It's correct.

I used all new gaskets and membranes from a Walbro repair kit. I used the tan pump diaphragm not the blue one.

The engine has excellent compression so I can assume it is pulling a good vacuum on the upstroke.

I sanded the reed block flat and the reeds are laying dead on with no gaps.

Puzzled!

Al

RTK

My Feedback: (1)

Pulse line?? Dry carb??

azalner

My Feedback: (8)

Pulse line is internal to the reed block and is unobstructed.

I pulled the cover off the upper chamber & flooded it with gas.

Al

raydar

I had this with my dle 30, tried everything including removing the cover plate and priming with fuel to no avail then descovered somehow my throttle was fully shutuntill the tx was half throttle?. To this day im sure I set the tx up right but somehow I must have went wrong. Ran great after a bit sub trim.

azalner

My Feedback: (8)

I have mine set up on a throttle curve and it's working correctly.

Al

3136

Is it possible something else was damaged in the crash? Crack somewhere?

captinjohn

So tell us how you are trying to start it in great detail. Does the engine pop...fart...smoke out exhaust a little...plug get wet....or any other thing you have not told us?????? It was crashed right....maybe air leak in manifold?? Ignition messed up or ignition timing. OK, your turn, whts happening? Thanks Capt,n

azalner

My Feedback: (8)

Good point!

A cracked crankcase will result in poor vacuum. I'll have a closer look.

Thanks

Al

RTK

My Feedback: (1)

Thing is you have fuel in the carb as stated before so it is pumping. Time to start looking on the ignition side if you can't get it to pop. As captain mentioned a little more info would help

azalner

My Feedback: (8)

I tried two different ignition modules. They both tested good. Also used a new plug.

One thing I did not mention. When I shoot a squirt of ether into the venturi, it fires right off. If it were pumping wouldn't the pulses from the crankcase keep the fuel flowing? Just asking.

Al

3136

If the fuel isn't coming up the line as stated in the 1st post it's not pumping.
Either a fault with the carb not drawing, or an air leak somewhere.
If it was in a crash an air leak is quite likely.

3136

I assume you have checked your plumbing inside the tank after the crash?

RTK

My Feedback: (1)

Apparently it is pumping fuel after rebuild, something not right here.

3136

I think he meant he manually primed the carb

RTK

My Feedback: (1)

Hmmm, you could be right.
All you need to make an engine run is spark, fuel and air. We know air is there so all you have to do is find out which one is missing to diagnose the problem and go from there. Do you have spark (at the plug, no short, at the right time) will it run on a prime but not other wises, etc. Take a systematic approach and he will have his answer.

doswings

May sound stupid and it's exactly the way I felt but I have a DLE 30 that I couldn't start. Put it in the plane and it was a no go regardless of how many times I flipped it. Primed it and it ran fine. Put it on a test stand and two or three flips was all it took. Got a good spark so figured it was the fuel line. Took the tank apart switched the lines same issue. Next step was the carb,- the rubber looked good but rebuilt it anyhow, same problem. The carb is in the rear and the firewalls recessed so every time I tried or check something the engine had to come out. Must have removed it and the tank a dozen times trying to check different things. I was ready to throw it through a window. It would start on a test stand two or three flips but installed nothing. While in the plane I made sure to push the choke leaver over as far as I could and it was closed completely. Because the firewall was recessed and the engine had a rear carb the only way you could see it was through the plane's nose with the fuel tank out and it looked completely closed. The linkage however did look a little off so I moved it over 1/16", I'm not kidding 1/16". Problem solved - apparently even pushing it over manually the chock was was binding due to the misaligned linkage causing  it to stay open ever so slightly that the carb wouldn't draw fuel. Starts up now with two or three flips to pop two more to run.

Scota4570

Check for kinks or blockages in the fuel line. Put your thumb over the carb, turn the engine over, if it does not draw it could be a blocked fuel line. This happened to me recently, turns out I had a kink in the fuel line.

azalner

My Feedback: (8)

OK, I went over the crankcase with a fine tooth comb. Not even the hint of a crack. The crash couldn't have been too violent. The crank was not bent - checked it in a lathe and had about .0001" runout. I changed the bearings anyway - you never know after a crash.

Now with regard to fuel tank plumbing, yes that was one of the first things I checked. I re-plumbed everything and even changed the tank and clunk. I use a Walbro felt clunk. Same result. OK, just to completely eliminate the plumbing, I strapped on a fuel tank to the fuse just aft of the firewall. It was a Fiji water bottle conversion so I could see what was happening. Only 6" of fuel line between tank & carb - same result.

Now to the choke being fully closed - good point! However I checked this to see if there was any free play with the choke in the fully closed position. Nope - no free play. That sucker is closed tight.

I'm just guessing, but what if the needle is not lifting off the seat? That will not allow fuel to reach the idle & high speed jets, right? How critical is the lever arm setting? How flimsy are the lever arms? I know it was a pain in the arse to get back in with the spring properly positioned.

I just ordered a new carb, which should be here sometime next week. Meanwhile, I'm going fishing to relieve the pent up stress.

Thanks to everyone who chimed in on this. I'll report back when I get the new carb.

Al

RTK

My Feedback: (1)

The metering needle could possibly be stuck, even a mal-adjusted fulcrum arm wouldn't stop the fuel from flowing when choked. You did open the needles after rebuilding. right?
When assembling the pump side you did put the diaphragm first (flapper valves) against the carb body then the gasket, and the reverse on the metering side??

azalner

My Feedback: (8)

Low speed needle - 1.5 turns
High speed needle - 1.75 turns

Quadruple checked placement of gaskets. Everything checks.

While on the subject of gaskets - I got two different thickness gaskets for the metering diaphram. One was .030" thick and the other was .019" thick. I tried both with the same result.

Again, I want to thank everyone who chimed in on this issue. Sometimes you have to walk away and come back later.

I'll post again after a new carburetor and a couple of nice rainbow trout.

Al