I've flown a few big S.T.s over the years and have never been happy with the carbs on them. Having heard so often that switching to the pricey O.S. 7D carb is a surefire fix, I've always been tempted to give that a try. Recently, I was looking at my Irvine 1.20 (nice engine!) and thought to check if its carb would fit my 2300 - it does - exact same diameter mounting flange (17mm). IMO, having run a few Irvines, I think that their carbs are every bit as good as O.S. I e-mailed Paul at Just Engines in the UK about availability and price. Paul responded offering a great price for the Irvine carb and even better price on Moki carbs, which in his opinion are an even better carb. Having a 2300, 3000 and another 3250, I ordered an Irvine and 2 Moki carbs to try. Reading a few reviews, apparently the Moki carb is a very, very good carb. I'm looking forward to trying this out this next summer. For those of you looking for a cheaper alternative to the O.S. 7D carb, give Paul a call. You might be able to turn your big tigger from an attractive paperweight into a powerful and reliable runner. I've run my ST2300 about 5 times on the test bench with my Irvine 1.20 carb. I like what I'm seeing. I can hardly wait to try the Moki carb!

Years ago when I flew a lot of Super Tigre engines-2500, several 3000s and a 3250-I found the carbs after the initial small throat carb just wouldn't work very well. At first we tried an OS 7D, but they, as you mentioned, are expensive. Next, we tried an ASP 1.08 carb. Worked like a charm. Our local dealer got them for us for $26! My 3000s would 1-flip start and never missed a beat with the ASP carb.

You did need the spacer ring that the STs used to have. In a pinch I have used aluminum flashing tape and trimmed it to a snug fit, then sealed with hi-temp silicone.

Is that a Sirex Wasp in your avatar?

The Magnum carb works great on the big Tiger's. This one is on my 3000.
This same carb was used on the .61 thru the old 1.20 magnum 2 strokes,
and is less than half the price of the OS 7D.

Don't get me wrong, I have a few of the 7D engine/carbs, they are tops !

FBD.

I can take the carb off of any healthy two-stroke glow engine and get it to start on one or two flips with only a few drops of prime. If the fuel tank height is proper, the carb has nothing to do with starting the engine. The carb only works when the engine is running and flowing air through the crankcase/cylinder. This is not happening when starting the engine by hand.

My G2300 throttled just fine with the stock carb. Later, some G2300 engines got out of the Italian factory with the wrong barrels in the carbs. This is a matter of record. Blame it on one of the sons that was running the business into the ground.

Apparently, the new G2300s from China have the proper groove in the barrel, so there is nothing wrong with those carbs that a decent engine tuner can't adjust properly.

The big Tigres are not set up for nitromethane. More than 2.5 to 5% at sea level is asking for a very cantankerous engine. Ditto fuel containing too much oil. I really got tired of seeing the big Tigres overheating and deadsticking because those flying them insisted upon using too much nitro in the fuel. Ditto the ASP 1.08 Redhead. Mine ran great on 5% nitro fuel with some castor oil in the mix. I used to watch several others at the field curse, stomp and declare how the big ASP was junk. Their fuel was 15% nitro Cool Power. Go figure. That fuel is good for the right engine. It just wasn't good for an engine with very high compression.

Why some people don't look at others that are succeeding and then emulate their behavior is something that puzzles me to this day. I don't look to see who is flying the largest or most expensive airplane. I don't look to see who is strutting around in their fancy clothes and telling others what to do. When I have a question about a product, I look for the guy that is flying it successfully. That'll work every time.

To this day, I don't understand why some folks are so enamoured with fuel using more than 5% in a two-stroke engine.

The 2300s are different critters compared to the 3000/3250s. The 3000/3250s don't like high nitro while many report good results with the 2300s using 10 or 15% nitro. Same goes for oil content - the 2300 needs high oil content, while the 3000/3250 needs low. Personally, I brew my own fuel for the 3000/3250 - 5% nitro/12% oil. Starting and power has never been an issue and I'm not saying that the stock carbs are outright terrible, they just don't modulate as well as (for example) an O.S. That rich midrange problem is not fun to deal with! Twice with the 2300 I'd had the engine load up on final and not respond when a go around was attempted. Both times the engine continued to idle and just wouldn't throttle up. For the record, this is the original carb that was first introduced without the dog leg groove - appears to be the same carb as in my 3250. The first time it cost me the plane, the second time I got away with repairable damage. Yes, you can get the stock carbs to run, but there are simply better carbs out there. The fact that so many (experienced) people have felt the need to change out their stock carbs really says something - you don't get that with O.S.! Anyone that really figures there's nothing wrong with the stock carbs - have I got a deal for you!

Oops, forgot to add, Yes Ed, that's a Sirex Wasp in my avatar. I flew that for 3 or 4 years but it died due to battery failure. Still have the Cad files and building instructions. Great little flyer. I've scratch built two other profile planes - here's a pix of my 3D wall...

the new chinese 2300 carb is an excellent carb. i would never change it- i had an old OS 61sf, which had a superb carb, and the 2300 carb is as good as or better than the carb on the 61sf. but if you have one of the older 2300s with a less than ideal carb then maybe these carbs from other engines would help. i run my 2300 on 10% omega and it is flawless.

ed

Thing is many don't think its right or there is something wrong with having to replace a carb ona perfectly good engine. So I ask this. How many of us replaced the old Rochester carbs on a perfectly good muscle car back in the 70's with a nice Holley????

i posted my comments to show my personal experience with the chinese 2300 engine and carb. i wonder about some of the problems some describe - i also have heard that the big tigers had carb problems so i decided to try the 2300. i am sure that the comments made are from modleres who are also describing their own experiences. but as mine is different from those i believe the readers here should know mine as well.

i think some of the problems described are due to carbs, some are due to tuning, some are due to fuel issues, fuel tanks, etc. some are also probably due to break-in - that is, the big ringed engines need fairly long break-in, and i question whether a gallon of fuel is enough for break-in on these bigger tigers. for my g90s it seems like they need between a gallon and a gallon and a half before they settle in to run well. so maybe a 2300 would need 2-3 gallons to get to the same point. i know mine needed close to 2 gallons before ir ran its best. and i have heard that the mokis need a fairly long break-in also. so maybe the 3250 would take over 3 gallons. i have now bought a second chinese 2300 and a chinese 3250 and this spring i will find out more about these engines. i am too wimpy to do break-in when it is 20-35 degrees out here in ohio, so i will wait until it's 55 or above .

ed

Daryl, did you make that tuned pipe setup in the photo?

thanks!

Ernie

I used to run big cats. Sold them all and went to gas for larger engines.

All my cats had the OS7D carb.

I picked up 300 RPM on the 3000 swinging a 20-6 Zinger on 5% Omega and a Tower plug at 6000' elevation. RPM on the bench was 7200.

One thing I quickly figured out about the OS carb was not to adjust it too rich on the high side. You had to adjust for max lean and then only back down about 2 or 3 clicks. Anything richer on the high side and it would die if you chopped the throttle quickly back to idle.

I couldn't say how the other engines ran after the OS carb was added, I bought them all used and they already had the carb. No way to compare it to stock carb.

Ernie - the header is a pattern setup. Can't remember the name of the fellow that made it, but when the 2300 first came out, a bunch of people used them for pattern running them inverted... which is what the header is for. This guy made a bunch of these beautiful wrap around headers and I managed to snag one new off the Marketplace. The pipe is a Macs quiet pipe I bough cheap off the Marketplace too. It had a big dent on one side, so I cut it open and straightened the dent out best I could and had it rewelded. That's why you see the heavy weld. I'm not looking for world class power - I don't fly competitively. I just want a nice strong & reliable sport engine. On that note, anyone thinking the stock setup is OK, the S.T. 2300 was much anticipated as a reasonable cost alternative to the O.S. 1.40, but after extensive service, many felt it just didn't measure up and was abandoned by most as a pattern choice. This says something too. Pattern flyers tend to be very experienced and extremely discriminating.

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And I am not saying that some ST engines cannot benefit from a different carb. I think the main issue is that some of the ST carbs flow too much air and lack proper atomization of the fuel. But I can point to several OS and Chinese engines that suffer similar problems.

Yes, you are correct, as you already know, that the G2300 is a different kind of critter than the larger ST engines. I'm not a fan of the larger ST engines. They were a fine first effort, but they lack the finesse of an OS 1.60, Moki or large MVVS. Still, I wouldn't put them in a bad category.

What I object to is someone dismissing the ST carbs off hand as not being any good. This is simply not true. Are there better carbs? Most certainly. And sometimes the better carb for a particular application may be of inferior average quality, but possess a small enough venturi tract to enable good atomization of the fuel.

Some of the kids are reading this stuff and are immediately trashing the ST carb on any ST engine without even trying it. I wish they would at least try the original. They might find an advantage in them (adjustable midrange). Or, for them, they might not. But trashing them out of hand prevents them from any possible advantage that that particular carb might offer for a particular installation. The ST carb shines with resonant exhaust systems because of the available midrange adjustment.

I broke the high speed needle on my 2300 tonight.[:@] It was bent and I tried to straighten it. Do any of you guys who replaced the stock carb want to get rid of your old HS needle and/or complete carb? I have the Italian made 2300 with the spacer in the hole the carb sits in. The HS needle is just a wire that is threaded and has a 90 degree bend at the other end. It is NOT this one http://www2.towerhobbies.com/cgi-bin...?&I=LXFY19&P=Z

I normally replace the stock ST 60-90 carbs immediately. The 2300s' carb is good, although sometimes too large to draw fuel well. The low needle is sensitive when you get it close to perfect. I agree with using low nitro with this engine, 5% Coolpower is all I will ever burn in a 2300. The Japanese engines are nitro hogs, they suffer with low nitro.

Engine tuning is some science and a lot of art. Someone knowledgeable with ST to apply the art will save lots of time and money.

Bill

Bills,
That maybe? is true but the very low price tag often only interests the newbies with low knowledge about the ST carb.
I havent had one single deadstick on my Supertigers since two years back and I can make any supertiger engine run very reliable but I can not make them run good[] unless the carburetor is changed.

The sad thing is that ST really makes good engines but doesnt seem too care much about the carb. issues[&o] and most sell out their engines for half the price of other brand engines with the good or better carburetors.

They havent heard the saying "customer is the KING" and should visit the sorry!!! I meant the OS fabric in Japan to learn something about customer requirements.

Kweasel,
OS runs good on 0-5% nitro and so does the Saito on 5-10%, but they can also handle a lot more nitro for the best operation and performance.

Does anyone have a needle or carb they want to part with? See post #13. You can send me a PM or reply here.

Anthony The needle you showed from tower will fit. You just take off the packing nut your wire needle screwed into. and use new style.

The new needle does not look like it has threads on the wire part. How will it screw in and stay sealed?
Here is a picture of my carb taken apart.

The broken needle you pictured is the same needle that almost every S.T.
ever produced has....even the c/l engines use the same needle. Maybe some
of the new stuff from China is different, I don't know. Any of the old needles
will work, from any S.T. engine.

There may of course, be an exception to this, which I'm sure someone
will be quick to point out.

In fact, here's exception #1....an oversize S.T. style needle. Same threaded end,
longer shaft.

Thanks Dave. I called Roger Armstrong and found out that same info. He is shipping me one Monday. He is a great person to deal with and knows engines inside and out.

FWIW. I ran the 2300 today and was able to tune it with the broken needle. I was running 10% Wildcat with 18% oil at an 80/20 mix. It was swinging an 18x6 MAS Classic. I got it idleing at 900 and wide open at 8200. This thing runs like a Swiss watch! I have never seen anything idle at 900. I could advance it from idle to wide open and it was smooth as silk. I guess the new carbs are the junk ones because this is the best carb I have ever had in anything! Roger told me the way to smooth out the midrange was to rotate the spraybar about 10 degrees either way from straight through the venturi.