ahicks

My Feedback: (2)

As far as starting, if the pick up is centered on the mounting screws, you can save yourself a LOT of trouble by just assuming the timing is "close enough". If you want to be a purest about it, and mess around making it perfect, go for it, but it's not going to change the way it starts. -Al

Cub Flyer Fresno

Got it running today! Since everything was out of the plane, I could see air bubbles in the line. I figure it must be pulling air from the pick up tube attachment to the cap. I filled the tank above that point so it couldn't draw air, and got it running. I let it set awhile, came back to it and tried to start it again. First flip! So I went and took care of other chores for the rest of today. Just got back to it... Won't start. Almost! But it would seem I'm right back where I started. I'll keep messing with it.

Cub Flyer Fresno

Ha! Yeah, that's right! Right after I post that it won't start again, I gave it another try. It runs! Again! 🤪

Cub Flyer Fresno

Well guys, I don't mean to beat a dead horse, but here I go anyway! Saturday afternoon I reinstalled the engine back into the plane. I tried to eliminate the air leak in the tank, if that was indeed where it was (I'm pretty sure it was). I made sure also that the pick up line connection on the cap was at the bottom to minimize the chances of an air leak inside the tank. After doing all that, then fueling in preparation to start it up, guess what! It was being a real bear to get started again!! What gives? Is it just the needle settings that need to be tweaked in order to get it to start easily? There was at least a lot of "trying to run" going on.

Along with that, let me make certain I've got the needle setting correct. This is a Walbro carb. I purchased from Tower. Would the initial needle settings be the same as the DLE carb.?

Truckracer

My Feedback: (19)

I've used four different Walbro carbs on 20 size engines and they all set pretty much the same. I have a spare here that came off a running engine and it is set at 1 1/2 on the High and 1 1/8 on the Low. I would think 1 1/2 or so would be a good starting point for both needles. Obviously, your settings may be different.

While an engine will usually start easier with the needles set, I have never found any great problem getting an engine to run with the needles too far open. Too far closed (lean) is another matter as gasoline will still ignite with a rich fuel / air mixture but might not ignite at all if lean. One thing many people try to do is start the engine with the throttle at full idle. There is when mixtures become critical and the engine might not get enough air and it will flood w/o the operator even knowing so. So, I always start with the throttle maybe 1 or 2 clicks above idle .... thats the stick position, not trim! This lets the engine breath and any fuel entering from the carb will be better atomized than if the throttle is at full idle. No this doesn't pose a safety problem and the engine just starts at a high idle speed .... it doesn't roar to life!

Keep up the good fight!

Cub Flyer Fresno

Thanks Truckracer! Yeah, I was trying to start it at a high idle to about half throttle the last time. I'll try the lower settings/stick position. I have just never had such trouble with DLE 20's, ever! I'll give it a try later tonight if I get a chance and it's not raining.

Never going to give up! At least not yet. 😉

Cub Flyer Fresno

Did you think I gave up? Nope, just took a break to let my thumb heal a little. Yep, after you've flipped the prop so many times with no good results, sometimes you get a little careless. Man that prop can slap the crap out of your digits!

Anyway, I pulled the engine back of the plane so I could take the carb of and look for any possible leaks. Think I might have found something. Look at the pics and give me your opinion.

Wet when bolt head seats.


Gasket is wet at top.

Truckracer

My Feedback: (19)

Right now I seem to need a crystal ball to see the photos.

Cub Flyer Fresno

Wow! They did come out rather large, but if you click on them they shrink up to size...? Just doesn't seem right. Posted them with my phone, so...

Truckracer

My Feedback: (19)

When I made my less than tasteful comment, the photos hadn't shown up on your post. They didn't show up until some time after you posted them. I actually like the large photos.

Anyway, If the gaskets on the reed housing are ok and the carb mounting bolts were tight, I wouldn't be too concerned about a bit of oil there or on the mounting bolt on an engine that had been in service for some time. Those bolts are exposed to the inside of the back of the engine so some oil seeping down the threads might be considered normal. If any doubt, replace the gaskets.

Cub Flyer Fresno

For what's it's worth, I didn't take your comment as "less than tasteful". 😉
Okay, so I put it back together, haven't mounted it on the airplane yet though. To tell you the truth, I'm just grasping at straws now. Guess I might be disassembling my Ultimate.

kmeyers

Cub Flyer
How do you tune your engines?

Do you have the carb gasket lined up for crankcase pressure for the fuel pump?

So many posts with now a couple pics, more pics please. The reed block and insulator block and gaskets would have been nice.

What are your needle settings @. L? H?

When the engine is out of plane and you are running it. How are you controlling the throttle?

Show a close up of the spark plug cap on all the way.

What prop are you using?

How much run time on this engine?

Are you the original owner?

I like people who don't give up, lets beat this *****.

daveopam

My Feedback: (9)

Not sure if you have looked at this. The first DLE i had was a 30. It was a PITA to start. When I pulled it down the reed block looked like it was smoothed out with 80 grit paper. I removed the reeds sanded it smooth with 400 grit and it has been happy ever since. May not be your issue but it can't hurt.

David

Joystick TX

There are two things you may try.

One is easy, and is probably not the problem, but it is quick. Check to see where your gasket is in relation to the carb pump, it's under the cover that is held on with one screw. On some carbs the gasket goes near the engine and one some it goes near the cover. If you aren't sure which way it goes, just reverse the order to see if it fixes the problem.

The second one is harder, but since you've checked and double checked everything else, I'm 90% sure the problem is with the front bearing seal. If it's leaking air, the engine will not run well. Since the engine was running okay and the problem just appeared, that is my best guess. The DLE 20 is NOT tolerant of a leaking seal. It is a relatively easy fix, just replace the bearing. Make sure you get one that has the right type of seal for the front. Replace the front and rear once you have the engine apart.

Truckracer

My Feedback: (19)

I agree the bearing seals could be a problem but both crank bearings have double seals so one is as important as the other. Replace both bearings when replacement is necessary.

Joystick TX

Good idea.

ZENGSM62

Read the thread, may want to check the pivot arm that works the needle and seat, there is a correct setting for it to work correctly.
I adjusted my DLE35 to help it not die when inverted.
May be worth looking at.
GSM

Joystick TX

I don't think that is the problem. He's had the engine a long time and it was working okay, then it quit. He replaced the carb. It would be a rare event if both carbs had a bad pivot arm.

The symptoms are more related to an air leak.

Cub Flyer Fresno

Sorry guys, had to take a break from it for a while. So, to start out, and per kmeyer's request, I took a few photos of my setup. My not be exactly what you want, but it's a start.

Now, to see if I can catch up on some of your suggestions/posts: Needle settings have been all over the place, from 1 turn to 2.5, maybe even 3! An easy one, seals... the cylinder head, piston, ring, and crank case have all been replaced. A seal at the bearing now is highly unlikely. Let's see, what else... I'll move on to what guys out at the field have seen,

So, knowing it was probably futile to try to get it to run at the field, a couple guys wanted to take a look. Here's what we did and noticed: A thought I had was that the tank was slightly elevated when on the test stand. So we took the tank out and one of the guys held it while I tried to start it. With a bubble in the fuel line we could see it moving when the choke was on. After the engine popped, the choke was turned off and the engine popped two or three times more, BUT... the bubble wouldn't advance! I would have to start the process again by choking until the engine pops, and then unchoke and get the same results. There doesn't seem to be fuel flow. That makes sense to me as I was getting those same results before. So now the question in my mind is why does the fuel not flow when the carb is not choked? One suggestion was made that the "float spring" may be to stiff. We disassembled the carb to check the diaphragm and replaced it anyway with a new one the guy had, but the spring seemed okay to him. After trying some more, we gave up.

So that's where I am. It just does NOT make any sense to me! Does any of this info trigger anything?

Really appreciate the help!!!!

Truckracer

My Feedback: (19)

What kind of fuel line are you using? I'm not familiar with a common clear line other than Versilon. Does the ceramic clunk flow fuel freely? 2 line system, are you filtering the fuel going into the tank?

I sometimes question changes some people make when they involve a component that has worked all along, such as the needle fork spring. If it has worked OK to date, it didn't get stronger sitting in the carb and is probably not a problem.

Cub Flyer Fresno

The gas line is PU. I've been using it for a while now. It lasts longer and is tougher than Tygon. The clunk is a Poulan ceramic filter. I also have one in my gas can. Again, I've been using those with all my DLE 20's and they have worked well. But just in case I did change the clunk in the tank to a new one. No difference. As for the spring, the guy that looked at it didn't think it was too stiff. And this is a brand new carb! The reason he suggested the spring was he had a problem with a Walbro on a, I believe it was, 30cc engine. He found the lightest acting spring he could at a Stihl dealer and hasn't had a problem since.

Truckracer

My Feedback: (19)

The PU line is good. The Versilon line I mentioned is PU. Few people use it.

I questioned fuel line because some cheap lines can leach out plasticizer into the fuel and it can coat the inside of the carb even blocking the screen in extreme cases. Not the case here.

DGrant

My Feedback: (4)

I still have some suspicions about one particular area. I'll look at it soon. There's a few things I want to see first hand. We'll hopefully have some time later in the week and get together.

Joystick TX

It seems like if you've replaced the carb, cylinder head, piston, ring, crankcase, spark plug, ignition, hall sensor, and reed valve, that you are not even working on the same engine that you started with.

One thing that should have been noticed when you replaced the crankcase and the bearings and the only thing left that I can think of that is left from the original engine is the crankshaft key.

The woodruff key may be sheared. You can check the timing with a good piston stop and degree wheel. Since you get a pop, that means you have fuel and spark, but maybe not at the right time.

If that is not the problem, it would be a good idea to pressure test the engine and looks for leaks.

Cub Flyer Fresno

Yep Joystick, you've pretty much said it, it isn't the same engine anymore! 🤣 But when I replaced the crank case, the bearings and all came with it. I have a feeling that once DGrant is able to take a look at it, he'll slap me in the back of the head and "well there's your problem!" 😅😂🤣 I hope you get that chance DGrant!