MartyH

My Feedback: (16)

I just received my new in the box Aviastar 46 engine from Sig Mfg. For those that don;t know, this engine is being sold for $49.99 I assume until they're gone. It was $58 delivered. Anyway, I thought I'd start a new thread for discussing this particular engine. PLEASE keep the thread on topic to the AVIASTAR 46 only.

MartyH

My Feedback: (16)

I received my new engine, assembled the carb and muffler to the engine. I can see where some people were having trouble. One complaint I have read about is the fit of the carb to the engine crankcase. I will tell you that it is PERFECT! Yes it is snug and it will not tolerate being inserted at any angle other than straight in! I loosened the carb retaining bolt and made sure it was slid to the open position. I inserted the carb which would only go in about 1/2 way. Then, on a wood table I turned the engine over so that the carb was sitting flat against the table and gently pushed. It slid right in. Snug the carb retaining bolt and thats one potential problem averted. I chose to use a used OS#8 glowplug I had laying around.
A number of people have commented, myself included that the fit of piston to cylinder when brand new is very tight. Well, once I installed a prop I found the pinch to be about what I would normally expect from a brand new ABC engine so yes it is tight but again, I'd call it about perfect. The instructions call for always using an electric starter to start this engine-they say to do this for safety reasons. I think that's just plain nuts and probably how some people are getting into trouble with the crank pins and connecting rods. I insist on hand starting all of my glow engines. I feel that an electric starter just allows one to bully an engine into submission and masks poor tuning technique. In my case, the engine at first was so tight that it wouldn't run. All the more reason not to take an electric starter to it. It probably took 100 flips by hand for the pinch to loosen up just a touch as it kept trying to start but couldnt make it through the pinch. Then, it started. After just 3 very short heat cycles the big pinch is gone and the compression feels wonderful. The engine starts on the first flip now and is beginning to take throttle well. As for the carb, it is silky smooth. I think this engine is going to be a winner short of discovering a brittle crankshaft.

So, what have other people's experiences been so far with this engine? I did read the post about a broken connecting rod. Sorry to hear about that.

bigedmustafa

My Feedback: (2)

I ordered three Aviastar .46s for myself and two flying buddies a few months ago. I brought them out to our club field when I received them to give out to the guys; one of my other flying buddies said he wanted one, too, and I ended up selling him mine.

I did get a chance to break in and tune one of the three engines. One of the guys put his on a Buhor SPAD that he'd built. We had a little bit of glow plug trouble at first, and I found out he'd put an old plug in his Aviastar .46 to break it in. We changed it out to an O.S. #8 and ran the initial break-in tank, alternating the needle from about 1/4 rich of peak to 3/4 rich of peak (typical of most ABC break-in instructions).

After the first tank, I recommended that we go back over the engine and double check the bolts. One of the big differences I've found between expensive engines and inexpensive engines is that the expensive engines seem to stay bolted together better. Sure enough, we found a little bit of play in some of the cylinder head bolts and one of the backplate bolts had started working itself loose. We tightened them back up quickly enough; it was also encouraging to see that the carburetor hadn't started coming loose.

After letting it cool down, we went to restart the engine and discovered that the new O.S. #8 plug had failed. I grabbed a new Fox RC Long plug from my field box (w/ idle bar) and we restarted the engine. The pinch was good after one tank, but no longer too tight to idle reliably. In fact, the idle was solid at around 3,000 rpm. We did a pinch test to get the low-speed needle fine tuned a bit and checked the transition. It was very, very good for a new ABC engine with one tank through it. I told my buddy to go fly his plane.

The Buhor SPAD flew around well enough for about 6 or 7 minutes, and the new Aviastar .46 performed admirably. It was turning an APC 11x6 prop around 12,000 rpms, and it ran beautifully all the way down into the ground. My buddy forgot to put the servo arm screw back into the elevator servo after adjusting his linkage, and the elevator servo arm popped off round mid-flight of his maiden voyage.

The trip into the dirt cracked the carburetor housing, which was a shame because his carburetor had worked great right out of the box. By reputation, that isn't always the case with the Aviastar .46.

My overall impression of the Aviastar .46 was that it was a very solid performing sport engine and a good value for the price. It broke in and tuned easily enough, and the Fox RC Long plug seemed like a really good match for it. Double checking the cylinder head and back plate bolts, especially after the first few runs, would be my only caution. I'd suggest that with any new glow engine, however.

I'd definitely consider ordering more Aviastar engines in the future, especially for projects like combat planes or float planes where I wouldn't want to put a more expensive engine at risk. Also, the larger Aviastar 2-strokes have a good reputation (Sig currently stocks the 1.50 and 2.00 2-strokes), and I think it would be fun to try one of those out on the right project as well.

jeffie8696

Ihave been testing the Aviastars .46 and .53 for a couple of years and Ihave come to the conclusion that being a startup company it has experience the prerequisite teething pains and hopefully has now taken precautions to make the quality product I feel it can be.
I have experienced the carb issues and yes it does happen but Sig is awesome about customer service so dont let that deter you from getting one.
Ihave to agree about the broken con rod issues, an electric starter really overpowers a tight engine. I like to see the engine soaked in fuel and hand turned to get it used to itself. And never would touch it with a starter until it had several tanks run through and loosened up a bit. That and pre heating the cylinder is a plus.

Conclusion: The engines are a good value and if there is a problem Sig is terrific about making it right.

MartyH

My Feedback: (16)

My 46 Aviastar has turned out to be a sweetheart so far. It broke in nicely today with a half dozen or so complete heat cycles. Only about 10ozs total fuel. It starts with just a flip and idles perfectly. Transition is clean and it screams on the top end. This one is going on a Nitroplanes Bobcat pusher. I can't wait to fly it. As soon as the engine has proven itself with a couple gallons in flight, I'm grabbing another one from Sig Mfg. before they're gone.

wcmorrison

My Feedback: (2)

I too have an Aviastar .46, used 15% nitro and all Castor for break in. Turned 12,500 to 12,750 with a MA 11 X 6 prop. Used the recommended idle bar plug and got an idle below 3,000 RPM. I used a heat gun to warn it up for start, it was too tight to hand turn. Ambient temperature was around 75 degrees outside, so it was not like I was in a cold climate. I had put after run oil in through the glow plug prior to turning the engine at all. It was so tight it squeaked. After heating it up, using a Sullivan starter she fired up. After the first run she was nice a lose with a pinch at the top. Ran six tanks of fuel through her on the ground. Always using a starter to start the engine.

BTW, Henry Ford added a starter to his Model T's and nobody is using hand cranks to start their cars anymore. Hand starting can be dangerous. I do not recommend it.

Cheers,

Chip

jeffie8696

I dont recommend hand starting without proper safety gear. I personally use a very heavy welding glove.
Ithink the manufactuer wanted to impress us with his tight "pinchy" engines so he went a little overboard.
Marty, great to hear it is working out. Seems you can always find a bad comment about something because the people with good things to say are mostly silent (maybe cause they are outsideflying a good engine).

ProBroJoe

What's there to say about the Aviastars that hasn't been discussed here before?

They're a $49 engine, keep your expectations low and one of two things will happen,

1. You'll get a "runner" and will be tickled pink that you got such a great bargain.

- or -

2. You'll get a lemon and won't be out much.

Read through the other Aviastar threads and count the number of Yays to Nays - that ratio is directly proportionate to one's odds of getting a good one.

jeffie8696

OR

3. Be like Joe and replace the carb with a cheap one from another engine and enjoy.

MartyH

My Feedback: (16)

Well, the reason to have this thread is to hopefully bring all the Aviastar 46 info into one thread. The other threads got lost or hijacked any number of times. My hope is that we can get to the bottom of the concerns with this engine because for some of us, it;s working out well. I'm hoping that maybe we can help those that have had issues or at least can explain why they have had trouble.
From all the other threads the overwhelming problem has been tuning the carburator. I can tell you that this is likely no longer an issue as my Aviastar is fresh from SIG and the carb functions perfectly. The only mechanical issue I have read about on this engine was one person losing a connecting rod.

ProBroJoe

I have to admit, I was surprised by the con rod issue, but you have admit how that must have been a kick in the teeth for that particular user (after replacing the carb in order to get a runner).

Sure Sig has been fantastic about correcting the carb issues, without a doubt, but think about the amount of grief these bargain engines have created for everybody involved - Sig included. There's probably what, a 25% dealer markup on these things? So Sig is potentially making about $12 for each one they sell, and probably losing 4X that for every one they have to fix (because of salaries, administrative fees, postage, correspondence, correspondence to other countries, etc...). I bet they can't wait to get that albatross from around their neck!

Being married with children limits the amount of time for my hobbies, so I am not in a position to spend my precious time fiddling with troubleshooting & warranty returns. Don't get me wrong, I love to tinker with engines of all sorts - I've even been known to design and build a few of my own - it's a hobby of mine, but... when I spend hard earned cash for a NEW engine, I expect it to perform as the advertiser claims, without having to send it in for warranty work or replace components. On the other hand, I'm a frugal SOB, so I've been bitten more than once.

-Joe

ScottMcM

My Feedback: (66)

I haven't totally given up on the Aviastar 46 yet. I had 4 of them(bought 2 and got 2 on a trade) before the rod let go on one, so I had a replacement. I have since installed it on the Cessna, and I'm gonna try again this week. I have, however, decided to spend more time running the engines on the ground, before I try them in the air...once bitten, you know. I've got to admit, the engines were sounding great together, and I was thinking to myself that I had still gotten a pretty good deal on some good engines..... and then one broke....oh well, maybe this time is the charm....also, I made sure to pull the back off the other engines and check the con rods. Everything looks good. Cross your fingers....

jeffie8696

After dealing with the carb issues on mine they have earned a permanent home in my hanger.

MartyH

My Feedback: (16)

Just for information sake Scott, do you use an electric starter?

ScottMcM

My Feedback: (66)

Depends on the engine, but yes, on the Aviastar, I did use an electric starter....however, I turned it over by hand to get the fuel to the engine,before I used the starter, and I noticed that it(they) loosened up quite a bit when the fuel got in the cylinder. After I was done breaking them in, I was able to start one of them (can't remember which one) by a simple flip of the spinner in the opposite direction.

ScottMcM

My Feedback: (66)

Tried to sync the Aviastar 46's again today. I had to replace the one that broke, and start over....again. Can't get the rpm's out of the replacement engine. I didn't even bother to use the tach. You could tell a big difference just by listening. I'm gonna check for a kinked fuel line and run it some more to loosen it up a bit. I'm a long way from flying, though.

SpinnerRow

Has anyone tried the .53? If so can you post some prop numbers?

jeffie8696

You will find the numbers in the tach reading section Ibelieve.

Ernie Misner

How many have had this particular carb issue like the fellow at our field: The carb rotor (barrel?) keeps freezing up in the carb body to the point where the throttle servo can no longer turn it. He removes it and polishes it up and it freezes up again in just a few minutes.

Thanks,

Ernie

ProBroJoe

Ernie, I had a very similar thing happen to mine, but the problem was with the spiral groove cut in the carb barrel. The idle stop screw had worn though the anodizing and was galling. I cleaned the burrs off the stop-screw and groove and all is well... well, no it's not because I yanked the carb off and am using a Super Tigre carb so I don't know how much longer my "fix" would have worked.

(An aluminum carb barrel? Why in the world?)

Anyway, hope this helps,

-Joe

MartyH

My Feedback: (16)

SpinnerRow, please start a new thread if you want to talk about any engine other than the Aviastar 46. I'm really hoping we can keep this thread on topic. Speaking of which, I am busy at work on the airframe I'm going to be flying my Aviastar 46 on. Its the Nitroplanes.com Bobcat 50 pusher. It's a twin boom, jet style airplane. Mine will have fixed gear because of the need for larger wheels to accomodate the grass runways at our club. This will be the testbed for my engine. It should be flying in a couple weeks.

ScottMcM

My Feedback: (66)

I ran two more tankfulls in the replacement Aviastar 46, and I still can't get the rpm's anywhere near the other one. I'm talking 1300 rpm difference it the two. I replaced the glow plug. I've checked all the fuel lines, including the ones in the tank. I disassembled the carb (Super Tigre) and cleaned it. I made sure the spray bar was in correctly.......The engine idles and transitions great, it just won't rev as high as the other. I'm running 10% Omega, and 11x7 apc props. One engine is turning 12,300rpm (+-), and the other is barely turning 11,000. Am I missing something?

grasschopper46

My Feedback: (2)

Hi guys just bought a aviastar 46 engine on nov. 10 just before I found this forum so I dodnt know whether to be happy or cry! so could someone please tell me how to break in an abc engine and what fuel to use???? I use cool power 15% HELI FUEL IN MY RAPTOR..

jeffie8696

There is a "break in" sticky thread posted here somewhere Ithink . The one thing Iwould suggest is using fuel with some Castor in the mix, dont need much maybe 3% would do.

MartyH

My Feedback: (16)

11 X 7 props? Shouldn't a 46 be running a 10 X 7? Are you running the same carburator on each engine?