Senior moments also occur!

Well...I'm a little frustrated and maybe someone can chime in with some advice. Mine is turning out to be a bit of a turkey. The carb is what I call "tippy". In other words, it runs like a watch on the ground, but does not do well with attitude changes. If the engine is idling and I tip the nose down (typical landing senario) it loads up and dies. If I lean the low end to the point where it doesn't die when I tip the nose down then it leans out when I tip the nose up. If I richen it up to where it doesn't lean out when I tip the nose up, then it loads up and quits when I tip the nose down. It seems like no matter what I do I can't find a happy medium with the LS carb setting.

I simply couldn't fly level enough to keep from having to practice my dead sticks. Finally, I resorted to on-board glow heat. This has helped, however the engine still doesn't run all that well IMO. Before the onboard glow heat it was about a 2 on a scale of 1 to 10. Now, it's about a 4...acceptable but definitely not great. It almost seems like maybe they sent me the wrong carb?!? Any words of wit?

....and it makes one hell of a MESS!

I would expect that this engine would benefit from a proper regulated fuel supply, such as is provided by a Walbro.

The engine shouldn't need anything to run right.

Do you have to correct plug in it? Could the plug be bad? What about the fuel mix? Is the thank 100% correct internally and in relation the the carb? Did you use the correct fuel tubing and stopper for gas? Is it broken in enough?

Pumping out a lot of mess sounds to me anyway like its still breaking in.

Bill S.

Note: Edited for spelling...

Subs

Yes, first check the tank and lines. Also I second checking the fuel mix. Sounds sloppy rich or too much oil if the tank checks out fine. How did it run on the bench? They have more than enough fuel delivery available when set up correctly. Mine runs within 200 rpm from vertical, to downline, and runs the same level or inverted. Also check to make sure you haven't flooded it and popped a head gasket. That would also affect the suction.

Hi , with mine I have the LS still very rich and it doesn't die . So rich that I've had more than 1 person come up and say it needs leaning out . I have left it where it is because its still relatively new and it doesn't die on me so its not doing any harm . I now have enough flights on it to start leaning it out some but I'm surprised how good it runs being that rich . It also has a different sound to it and the HS needle I found is somewhat sensitive and I also have that slightly richer than normal but it leans out enough in flight to run ok. I'm assuming that u don't have a blown head gasket which gave me a lot of trouble until I've put the metal and graphite gasket in . Maybe you have the early version like me that only came with the 1 gasket . If everything is ok mechanically with the engine I would try running it richer than u would normally would with a glow engine . No crud in the carb ? Cheers the pope

It sounds like you were not running muffler pressure with the engine. Are you using muffler pressure?
What type of fuel filter are you using? Some filters are more restrictive and also tend to leak.
What about the fuel tubing and how it fits on the fittings and tubes. If they are loose it then means they leak.
I typically use little zip ties on all the tubing where it mates up with tubes and fittings, even inside of the fuel tank.
Tygon tubing and the clear plastic tubing tends to get more soft and has a tendency to slip off of the fittings.

Thanks guys for the info. All the obvious stuff is good...fuel lines...tank...plug...fuel...etc. The motor's definitely broken in and the compression's tight as a drum (the "mess" I referred to is due to the fuel having so much castor oil in it and a far higher oil content than what you'd burn in a regular gas engine like my DLE 20) The motor is plenty strong at the top end so that pretty much rules out any possibility of a head gasket issue and it's never been flooded either. The issue is clearly low speed fuel regulation, or more accurately, lack thereof.

Now for an update: I flew Sunday night and it redeemed itself a bit. Three flights, no deadsticks, ran better than it ever has. Here's what I did: I richened the LS just barely enough so that it wouldn't die of fuel starvation when the nose is tipped up. Then, I sped the idle up to where it was just fast enough to where the engine wouldn't die when the nose is tipped down. This resulted in a workable compromise with the only downside being a 3700 rpm idle. However, I'm using an APC 12-5 prop (which both the motor and the plane really seem to like) and with a 5-pitch prop 3700 rpm is actually plenty slow enough to land the plane. I see guys all the time fiddling with their engines trying to get that slooooooowwwww idle and I've been guilty of that myself. The reality is the idle doesn't need to be 1500rpm. It just needs to be slow enough to land the plane.

If it continues to run like it did on Sunday I think I can upgrade it to about a "6", BUT, that's only when running onboard glow heat. I like the concept of this motor, but IMO the carb needs a little work and they need to find a way to fit needle bearings at the bottom of the rod to get the needed oil content down. Thanks again for the info...gotta go earn a living now!

You know, it might be something with the gasoline you are using up there in Illinois.
Down here in Texas the plain regular pump gasoline at the gas station works fine. But in my case it is unknown as to how much ethanol they put in it though. They say on the gas pump that it may contain up to 10% ethanol. But it could be less by quite a bit too. Thus the OS P3 Ultra Hot glow plug works fine for me, I do not need a on board glow ignitor to be kept on with it.

Just because the subject of checking gas tanks came up, W8YE passed on to me that he thought he had checked everything about a year ago and still had engine problems. Finally, he disassembled everything in his tank and found the copper tubing running thru the stopper had a small crack in it right where it couldn't be seen. He now advises everyone to change their fuel tanks about every year, and to literally check every part when you are chasing problems.

One other thing we both found out together on one of my engines... Fuel line inside material degrades, softens, and begins to collapse after a period of time. In my case, the vent line from the muffler was collapsing after a few minutes of hot air and causing a loss of fuel tank pressure. BTW, his hand operated fuel pump stopped working a few weeks later for the same reason.

While it is true all the gas in a given region comes from one refinery, I have seen the local jobbers dump their milk can of stuff in their gas before it is distributed to the gas stations. So yes there is a slight difference from branded gasoline to unbranded (or low cost) gasoline. All gasoline has to meet certain standards and the Octane is so posted on the pumps. Also posted is the max amount of alcohol added. Until recently, here in Texas out lying areas had no alcohol mixed in the gasoline. But alas, that has changed, all the gasoline seems to be blended now with alcohol. You could tell the difference because gasoline without alcohol you got better gas mileage. The alcohol does not have as much energy per gasoline and degrades the overall performance of the engines.

I am curious as to the use of 93 Octane versus 87 Octane gasoline. I suppose the 93 burns a little slower. Most modern automobiles have computer chips and sensors that allow the use of lower Octane fuels without any performance problems.

This is very interesting and could trigger a fuel shift. I would imagine you would need about 10% or so lubricant in the fuel. Gasoline does have some lubricity so you would not need as much oil in the mix as alcohol fuels.

Why would you need so much oil in gasoline? Gas is already a bit oily comapared to methanol.

Lately, in several ARF planes I looked at the included fuel tubing for the fuel tank had debris inside the tubing. What looked like tiny white bits of styrofoam or something. Now then someone else wound up with a length of fuel tubing that had a solid section inside and it wasn't hollow there at all. It drove them crazy until they figured it out. Plus yes I have seen brass tubing that was cracked before too. Plus tubing that is loose and doesn't fit on the brass or copper or aluminum tubes well or the fittings for that matter and tends to slip off easily. I like to use clamps or small Zip Ties on everything to help keep the tubing from coming off. Also some fuel filters could leak too. We used to have trouble with the two piece aluminum filters years ago leaking at the joint. The longer see through plastic filters can also leak after a while as the tubing can get soft and not fit on the fittings snugly anyumore, they need clamping too. I use a fuel filter on my engine and I noticed the other day that the filter had captured some little bits of black plastic in the screens.

I do know that with my engine only using like 3 ounces of fuel per flight, I can sure can get in a lot of flying off of a gallon of gasoline. That is something like 43 to 45 flights a gallon of fuel at 10 to 15 minutes a flight. I am still working on that first full gallon through my engine, but the gallon jug is getting close to being used up now. Depending on how much flying you do in a year, you might have to refresh the fuel jug from time to time if the fuel gets too old.

He might have meant that having more alcohol content would require more oil added due to reduced lubricity. But I imagine NV Engines have factored that into their oil ratio requirement already.

This brings up another question: Some ARFs come with plastic fuel tank tubes instead of brass or aluminum. Would those plastic tubes be OK with gas?

I have to admit that pressurised fuel tanks with the tubing, clunks, and filters are a real pain for me. I wish there were an easier way. I know with the bigger gassers the carbs are pumped and the tanks are not pressurized, making it a lot easier, IMO.

I do not use those plastic tubes that come with the ARF's fuel tanks with gasoline engines. But I honestly never tried it. Heck I don't even use the plastic tubes with glow fuel either. On some ARF's I do not even bother using the included the fuel tank as it looked too flimsy to start with too.

I know what you mean regarding the questionable fuel tanks included in some ARFs. The first plane I had my Norvel AX-40 in had one of those bad tanks and I fought it for 2 years thinking it was the engine. As far as I could tell, there were no leaks in the fuel system. I changed all the tubing, but still had trouble. In the end, I replaced the tank and the engine ran perfect. I never figured out how that bad tank malfunctioned, but was glad to finally get my engine to work properly. Since then, I am very choosy about the fuel tanks.

On most cars they have a ping sensor that retards ignition. So on my Jeep which is supposed to use 93 you will get slightly lowere acceleration and worse gas millage on regular. On the interstate this is about 21 MPG on high test and just below 19 on regular.

Geeter, the normal amount of oil for a alcohol engine is anywhere from 10% (large engines like 1.0 cubic inches) to 25% (small engines like an 0.049 cubic inches). Saito and YS recommend 20% oil. A 6.5 CC engine is a basically a .40 cubic inch engine. Typical .4, or as we say a 40 sized engine, uses 17 to 18% oil in the fuel. The engine does not have roller bearings like a gasoline engine does as found in a weed eater or DLE engines as an example. Those gasoline engines use anywhere from 4 to 6% oil in the fuel.

Can you use less? Of course you can but you run the chance of losing a connecting rod since it sometimes has a bushing but most times does not even have a bushing on the crankpin. It is as we say, your engine do what you want with it. But if you want it to last for a long time, then use a lot of oil in the fuel.

You will quickly seize a piston at 6% as the motor runs much higher compression, rpm, and temperature than a DLE.

Also, a 12x5 is too large to get good performance from the motor. A 12x4 is ok but most planes would like the 11x6 better

It is also smaller and without roller or ball bearings in the connecting rod. But the higher lubricity of gas over alcohol should bring the oil requirement down, not to 6% though. I suspect you could get away with 10 to 12%. What was the manufacture recommending?

As I learned only last Sunday, up here in Canada-land I can buy regular gas from one Shell station and it has ethanol. But at another it could be ethanol free (which is what I wanted for an antique engine). I asked the owner of the place with ethanol free regular how that works, and he said that they can get whatever he wants at the blending station, but because he has so many agricultural customers in his area (i.e. farmers) that have machines with carbs, he gets and sells ethanol-free regular blend only. Live and learn.

MJD, I ran into a similar scenario last winter in the Michigan Upper Peninsula. Some gas stations sell ethanol-free premium gas for use on snowmobiles.