I made the comment because if the engine is properly tuned, 5300 rpms seems low, but it seems that you are happy with it. The statement in the manual that it will handle a 26x10 is impressive. I haven't seen any engines this size turn a 26x10, so it must be very powerful.

Good luck solving your problem.

-Ed B.


The manual says I will take up to a 26x10 2 blade so I dont think it's over propped. 24x10 should be the sweet spot for that motor based on what others have ''posted'' I have not yet confirmed this for my self.
[/quote]

Guys,
Along with my list of to do's a couple of people mentioned that I should just rebuild the carb as it doesn't take very long and if the carb has been sitting for a couple of years chances are either the diaphragm has gotten a little stiff or one of the gaskets may have gone bad. Unfortunately I'm not having a whole lot of luck in tracking down a rebuild kit for the Walbro carb. I've take a couple of pics maybe you can help track this down for me.

First picture looks like 21-249 9-4 no hits on this at all. Second picture looks like HDA 18?? maybe 98 it's not very legible, then under it says 411. There are several HDA carbs. But the manual I tracked down didn't look anything like this one.

Anyone that knows this engine and has rebuilt this carb could chime in I would greatly appreciate the help.

You can see the number plane as day

HDA189 B

16.66 mm

Gasket/Diaphragm kit D20-HDA $6.83

http://wem.walbro.com/walbro/product...amp;Series=HDA

Why ,this was just getting fun.
BCCHI

I know Bill.

Why don't you start another thread on this subject of voltage vrs current draw and you guys can have it out as long as you act nice.

Back to the Original Posters question. First of all if the battery requirement is 4.8 to 6 volts, His battery is fine.

Look, the engine sat up for a year. Be real about this and buy new gas and run your engine at 32:1 ratio or whatever you are comfortable with. The engine you have likes to overheat if it is not vented properly and not set up on the needles correctly. This is aconverted glow togas motor and since the last time it was run I am sure the conditions have changed.

Take a tachometerr and readjust the low and high end settings to make sure you are not running too lean. Double check youor timing as well (28-32 degreesBTDC).

If you decide to rebuild your carb make sure the reeds are put back on exactly the way they came off. They do not like to work backwards.

E-mail me if I can help you out further.

Glenn

Thanks for everyone's help. I've ordered most of the stuff. I'm just trying to find someone that carries the D20-HDA gasket kit. One thing I noticed when I took the carb off is it wasnt on very tight at all. The bolts were not on very tight. When I took the one screw off and looked under the askets I noticed that there was a lot of debri on the bottom of the little screen. So I'm assuming I had multiple problems lots of crap in the screen and possibly the engine stopped due to air leakage from the carb. The gaskets look good to me but then again better safe than sorry. Should I use blue loctite on the tips of the bolts to keep them in? One other question does anyone know what the gap is on the spark plug. I droped my accidently and think I might have messed iup the gap, glad I have another on order.

Not sure on the gap. i bet you could call Horizon and they can give you the answer on that one. I was going to suggest you clean your screens. If I am not mistaken that particular carb has 3 screens. 2 of them you can see and the other one is hidden (very small). The carb overhaul kit comes with the screens I believe. However if you take some clean fuel and some compressed air when you have the carb apart you can blow on the backside of the screens to remove the debris. The small one you must back-flush with fresh gas. It is a chore to remove and re-install the screens so if you can clean them and blow them out from the backside it might be better for you.

Also on a side note. If you are running in-line filters on your fuel hoses they need to be cleaned as well.

I was thinking as well, If your fuel tank has a clunk/filter make sure it did not come off as this will allow the fuel line to "float". The fuel tubing has a tendacy to work harden on the neck of the clunk and can break off leaving the line free to float above the fuel level.

Looking at the picture of your spark plug the engine appears to be in good health. I would, after cleaning your carb make sure the needles are set properly using a good tach.

Glenn

My Evolution 35cc instructions detail 7.2 volts as a minimum. Check the manual or call Horizon. They have an excellent customer service department.

Fresh gas is cheap. Dump the old stuff in the mower!

The CM-6 gap is supposed to be .7mm to .8mm

About .025" would be fine.

Guys even though your engine may be the same name brand (Evolution) it does not mean it runs on the same voltage requirement. The carbs are more than likely different as well. As are the internal workings of theengine.The original post clearly says it is the older design. More than likely the manual is readily available online from Horizon or if you search the web, if I was a betting man you could find the original manual somewhere on-line.

Dont mean to berude just take the time to read an original poster's post then comment if you have first hand knowledge.There is nothing more confusing thanwhen a guy responds to a question andthe advice givenmay be completely off track to the original question. (kinda like this post now.)

Dont mean to flame or berate any of you. I know I would appreciate the help too. But that said I would want my question answered directly and not with a lot of theory.

Anyway Just saying.

Glenn</p>

Glenn,
I posted the original link to the manual back on post 20 I'll post it again here below. http://www.horizonhobby.com/ProdInfo..._58_manual.pdf unfortunately it's not very detailed it's only 6 pages.

Look at page 8. A 600 Mah Battery will last 1.5 hours. Nothing wrong withthat. I have to ask you now how do you tune your engine?

A few things that I've noticed that could have cuased the engine to stop mid flight.

So I took the carb apart I noticed two things. 1) Both bolts were pretty loose. I could have used my fingers to loosen one of the bolts. I noticed that no loctice is used. Should I use a small drop of blue loctice to tighten the bolts?? 2) Once I had the carb apart ('im giving up on finding a rebuild kit for now) I noticed that the small screen that sits down inside one of the openings had a TON of what looked like little tiny rocks but very very small. I took a can of compressed air cleand as much as I could. I didnt want to brush it with anything but I would say I got 99% of it cleaned. I also used the compressed air to blow out the other openings. I used some brake cleaner to clean everything while it was apart. I did have all the rubber diaphram and gaskets off when I used the brake cleaner.

I also found the following. I took the gas tank apart. 1) I noticed that whom ever built the tank before me used nitro fuel line instead of gasoline compatible line and used it it on the fuel line that feeds the carb. NOT GOOD the nitro fuel line had completley started to break down. The clunker had fallen off so I'm assuming that the fuel line might have been floating at top of the tank sucking in air instead instead of fuel at the time the engine stopped. I would have thought that I would have seen air bubbles in the fuel line when I was doing my preliminary test runs but don't remember seeing them. Anyway along with new fuel lines, spark plug, and new battery I think I will have resolved all of my issues.

Anyone recommend a good inline fuel filter for my gas can that fits medium size tubing that can be found at a local automotive store?

Just buy the inline filter at your local hobby store. While there buy some Tygon tubing and replace all of your fuel lines and if it was me I would also replace the fuel tank. When you go to re-install the carb just make sure the bolts/screws that hold it on are not overtorqued. If you use loctite use the blue loctite not the red. Put only 1 drop on the bolt AFTER you have ran it through the spacer block. DO not let loctite touch anything that is plastic.

1 drop is enough dont overdo, the more loctite you use the harder it is to remove the carb in the future. Snug the attachment screws up snug but dont overtorque. Wish I had a torque value for you ,but if you have turned wrenches you know what I mean. Just snug it and monitor it. The loctite will do it's job.

You did what I would have done as far as cleaning the screens. As long as the diaphragm is not ruptured / torn you should be ok.

I believe that your engine may be running incorrectly due to the RPM figures you quoted earlier. Do not be afraid to adjust the needles. You will hear many ways to do this but here is my way. It may not be the way everyone else does it, but it works and works well. As an example I am on another thread and I dont believe anyone is turning the RPM that I am. And I am still running on the rich side.

So all that said here is a good way to tune for best performance. If someone here knows a better way speak up.

Start the engine (I use a test stand) you can do this on the plane but more difficult to do. Let it warm up for a few minutes.

Go to full throttle and adjust the high end needle until you achieve max RPM with the prop you are gonna fly on. Then back off the top RPM about 100 to 150 RPM. (More on this later.)

Go to idle and adjust your low end needle as follows:

lean and watch the tach. You want to see the engine just start to drop in RPM when you are leaning. Now richen until you see it drop off on the rich side. The position of the screw in-between the rich and lean settings is your sweet spot.

When you are adjusting the needles only turn the needles about 1/16 at a time. Gas engines are very sensitive and dont need the 1/4 turns you might do on a nitro motor.

Now when you have the engine set as above When you put your cowl back on, the High end adjustment that you backed off 100 to 150 RPM you will get back, as when you fly, the air will pass over the velocity stack inside the cowl and give you back that RPM. With the cowl on, the engine tends to want to go to the Rich side.

Now all of this is a little overwhelming I know. Bear in mind that I am assuming that your engine is set up on timing correctly.

Man I hope you get it going again and find some more RPM in that great engine. The Evolution series is awesome. By the way a little off subject but I think Evolution has a copy cat. Can you say OS-gt55?

Good luck. Keep us informed.

Glenn

Sorry.
BCCHI

I am always nice,too old and dumb to be any other way.
Now Grumpy,thats a different story.
BCCHI

Don't be sorry, you are 100 percent correct...You sound like Daffy, been talking to him lately ?

I think this explains alot if I can get it posted, if your ignition was designed for 6volts and not 4.8v, 25% would not be wasted going through the heat sink of the regulator on the ignition. I will send you what I found to your e-mail address because I can't get it to upload and post since it is from flying giants not rcu. this proves my point in a round about way. I enjoy all your feedback it is a learning experiance.

Delete my post, when it doesn't support your old boys logic, RCU you are a sorry lot, I will not come to your site again and will visit flyinggiants from now on. w8ye you SUCK as a moderator, plain and simple!

Kurt 2022:
Listen dont get all butt hurt. But when you start throwing out battery voltage and Ohms law the original poster had an engine problem not a battery problem I am sure you are very knowledgeable howeverr the manual the guy posted clearly says on page 8 it is a 4.8 - 6 volt ignition system. They guy had 5+ volts left in his battery. As well the manual states that a 6 Mah battery will give 1.5 hours + of flight time.

I am sure if you had a question you would want it answered in a direct way, am I right? I know Ohms law and V-I/R as well. I just dont see what it had to do with the original question.

My 2 cents worth.

Glenn

Ok guys next question: I may or may not have previously stated that I'm fairly new to RC. I'm sure you might have guessed that by now. I've got a 3 line fuel system for the fuel tank. One line for fuel-dot. 2nd fuel line for the vent and 3rd fuel line goes to the carb. Very simple setup. My Question is regarding the fuel dot line. Do I add a clunker and a small piece of fuel tube to that line inside the tank so it's easier to fuel and empty the tank with out having to flip it over? Is there any kind of issue using two clunkers in one tank? Or should I be doing something else? What are your thoughts.

On a positive note. I've replaced all the fuel lines, inside and out, replaced spark plug, cleand out carb, got a new batch of gas. Got a new battery now I have to figure out where to put the stupid thing since it weighs twice as much as the original. I'll have to redo CG. I'm strongly considering using my 1400mAp battery for now. Too bad it's 10:00pm and I have no lights outside I would be trying to get her started right now.

Use the two clunks

Hi!
If Horizon only could use the same name for their engines the rest of the world use, MVVS!

I assume you have the older ignition that looks like this, new to the left.
The older Vlach ignition system runs on 4,8V-6V.
The new one 6-8,4V.

Of course you must use a clunk in the tank! How could the engine/carb otherwise get fuel???

Jaka,
It doesnt look like either of those. But it does say 4.8v, the 4 is covered up by the zip tie. Also my post clearly said use a clunker on the Fuel DOT line. I decided to just use a longer brass tube and bend it 65 degrees facing the bottom of the tank instead of the clunker.

Good news is I got her started this afternoon. I just need somoene to hold the plane while I do the fine tune adjustments. Hopefully will have her in the air by Saturday. Thanks again for all those that helped out.