30.5cc engine. Maxing out fuel flow on a 1107 carb on my heli. Need more fuel and suggestions

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sm1nts2escape said:
Thank you for that and I think we can agree to disagree partly on the governor tuning part. Also, I want to apologize for coming back a little stronger than was needed. I had a bad day and should have let most of it go and that is on me. Please accept my apology. Now for some news. I took the heli out yesterday primed the carb first then couldn't get it started. After richening up the low speed I got it started and got massive backpressure through my clunk which created a foaming tank and then my primer bulb filled with air. After I got the air out of the primer bulb the engine died from going rich. I leaned it back out and it seemed fine on the ground and fourstroking slightly with a touch of smoke at idle like I like. After take off as soon as I put it under load the engine was leaning out much more drastically than before to the point my governor wouldn't hold it anymore (overshooting rpms after coming off load) and I was hitting throttle hold to land it and let the engine smooth out/cool off. No matter what I couldn't tune it out so I completely redid my vent line at the field and it had no change at all to the tune so I took the heli home and inspected my carb. I found an airleak on both of my 1107 carbs in the exact same spot plus a couple specks of dirt but nothing more. I am wondering if when the engine is pulling a hard vacuum air is rushing through here and messing with my tune when doing those maneuvers that put heavy load on the engine/vacuum on the carb. I have a 990 that is being delivered today along with some new gaskets so I can see if the 990 has the same leak and if it behaves the same although I doubt it will as I said before I have some friends running them without issue and my friends that are running the 1107 had the same issue in flight as I am having. Also in regards to the comment about large scale flight I figured you guys would have done more testing on this carb then them so came here first. Sorry again.






I've had many and have built over 40 cars now. From modified imports like FD rx7s to souped up hotrods. My favorite out of all of them was my 85 Chevy shortbed with a built 406/th400 running a Holley Truck Avenger 770 Steel bodied carb. The new ones are aluminum to save weight/money.

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You know what, it takes a big man to admit when he's been wrong.

I know for myself and I can probably speak others here that your change in attiutude is appreciated. (y) :)

I still wish you luck.
 
1Coopgt said:
Dude I found a carb for you. You said you have a lot of experience tuning engines/carbs so I know you got this. :unsure: :ROFLMAO::ROFLMAO::ROFLMAO:
View attachment 73598

Now that I've got that out of my system . You really should be listening to Sean . He is one of the most knowledgeable people I know on this forum. You came to this forum asking for help and then you are nice enough to totally ignore the folks that are trying to help you. Either take the flight stick out of your ass and start listening or take a freaking hike . This is going no where and you're just being arrogant. Good luck . Cool helo.
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sm1nts2escape said:
've had many and have built over 40 cars now. From modified imports like FD rx7s to souped up hotrods. My favorite out of all of them was my 85 Chevy shortbed with a built 406/th400 running a Holley Truck Avenger 770 Steel bodied carb. The new ones are aluminum to save weight/money.
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Dannng coop, he showed u :ROFLMAO:
 
Drunk Made It GIF by Mammoth Screen

Oh my glad I haven’t been following this thread. Seems to be a bit of a dumpster fire👀
 
So first, thank you. I appreciate your sentiment.
I have thoroughly tested my 1107, 990, 668 carbs for rc use.. The throttle shaft leak would be minimal and although I haven't gone testing them, they are not sealed, so it's no surprise that you could get a bit of air forced through them. When I get some free time, I'll pull the carb off one of my rigs and test it.
I have been doing a bit of research into gasser helis. I have yet to come across anything about carb settings, other then referring to engine manufacturers manual. I have contacted trm about their tuning procedures for static rpm, vs governed rpm. Unfortunately I can't speak with the utmost accuracy on throttle curves in gasses as I only had e machines. I will respond more in depth once I've concluded my research, and have a better understanding of this particular governor system, and how it interacts with the throttle maps (v or u curve) within a cp heli.
I do suspect from your most recent post I'd be looking more to an engine air leak. A simple pressure/ vacuum test can confirm or deny this. I believe with the conversion kit you've used, it's not terrible to remove the engine in the event this becomes nessisary, how ever it can be preformed in chassis and will allow you to at least confirm the intake and gaskets are sealing properly.
Have you recieved your tools for working on the carb yet? I have put together a reasonably decent thread on setting up carbs. I haven't touch on pop off pressures as I haven't had the dedicated time to do it properly and photograph the process. How ever it's not a difficult process and I would be happy to explain how to do it.
 
Seandonato73 said:
So first, thank you. I appreciate your sentiment.
I have thoroughly tested my 1107, 990, 668 carbs for rc use.. The throttle shaft leak would be minimal and although I haven't gone testing them, they are not sealed, so it's no surprise that you could get a bit of air forced through them. When I get some free time, I'll pull the carb off one of my rigs and test it.
I have been doing a bit of research into gasser helis. I have yet to come across anything about carb settings, other then referring to engine manufacturers manual. I have contacted trm about their tuning procedures for static rpm, vs governed rpm. Unfortunately I can't speak with the utmost accuracy on throttle curves in gasses as I only had e machines. I will respond more in depth once I've concluded my research, and have a better understanding of this particular governor system, and how it interacts with the throttle maps (v or u curve) within a cp heli.
I do suspect from your most recent post I'd be looking more to an engine air leak. A simple pressure/ vacuum test can confirm or deny this. I believe with the conversion kit you've used, it's not terrible to remove the engine in the event this becomes nessisary, how ever it can be preformed in chassis and will allow you to at least confirm the intake and gaskets are sealing properly.
Have you recieved your tools for working on the carb yet? I have put together a reasonably decent thread on setting up carbs. I haven't touch on pop off pressures as I haven't had the dedicated time to do it properly and photograph the process. How ever it's not a difficult process and I would be happy to explain how to do it.
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I appreciate you taking the time to reach out to them although I am in contact with Al and a few of the other guys weekly and sometimes daily. I now have a new 990 bolted on along with new gaskets that I port matched and even port matched the vacuum hole through them. I have the heli in the car and ready to test again quickly this afternoon. It should only take me a couple minutes to have it tuned in pretty good but I don't have enough time to throw a few 100% smackdown flights on it to make sure the engine temps stay decent so I will only be about 95% tuned in for this headspeed. If it works I can get a real flight on her Friday for some good action and will take a video if possible. Might do a quick video today just of my tuning although it will be boring. I received some of the parts/tools. I got the lever gauge along with the spiral diaphragm but haven't ordered the pressure test kit yet. Still waiting on a spring kit to come in as well.
 
If you all don't mind me switching subjects for a minute?.. Since I got into gas helis I realized the rc gas cars/trucks have come a long way as well. I remember when they first came out with the hpi Baja gasser but it was pretty slow. Now I see the gassers are crazy powerful. I have watched a few videos like this. Man that is freaking awesome! Do they make 2 speed transmissions for them? I think I need one. Sorry, just had to say that.
 
sm1nts2escape said:
If you all don't mind me switching subjects for a minute?.. Since I got into gas helis I realized the rc gas cars/trucks have come a long way as well. I remember when they first came out with the hpi Baja gasser but it was pretty slow. Now I see the gassers are crazy powerful. I have watched a few videos like this. Man that is freaking awesome! Do they make 2 speed transmissions for them? I think I need one. Sorry, just had to say that.
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Yes, they do. Most are utterly garbage. There are a few decent ones for mcd and the baja platform.
The pressure test kit doesn't have to be a walbro item. I use a mity vac. It does pressure and vaccum as well as having a Guage attached. There are several other brands that can be had off amazon and ebay for varying amounts of money.. Block off plates are easy to make. The carb is pressure tested "wet" needs fuel in it to check pop pressure accurately.
 
Ok. I guess Ill have to do some more digging because everything I found showed them being tested without plates and dry.
 
Update* The 990 worked perfectly. Low was at 1 1/8, high was 1 5/8 - 3/4. I could keep the engine at 100% output without letting it take a break for a quarter of a tank without it going lean. With the 1107 I could only beat on it for 5 seconds last time before it started going lean. I am assuming it is the pop off spring in the 1107 but will not be able to test that out till a few weeks from now. Either way I am happy as I can now safely raise my rpm without fear of running out of fuel. Next time out Ill raise my rpm and see what she can really do. I had a blast yesterday for those two tanks and wish I could have gotten a video but it was 90* outside and my phone was overheating when recording. All I got was a short video showing my plumbing etc. This weekend Ill get a good video of it getting a thorough beat down. Also I could tell the 1107 made about 5% more power than the 990 but it doesn't matter if I cant get fuel for aggressive flying.
 
RcJunkie13 said:
cool, so there was something wrong with your carb, just go over the 1107 and you could mabe fix it
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I personally tried two 1107s. Everyone I have talked to that has tried an 1107 or is trying one now is having/had the same issue. Some are having slightly less of an issue as me but aren't pushing the heli as hard. I have one friend that burnt his engine up and two others I know of have their needles at 3 1/4 currently. Hopefully a popoff spring will fix it.
 
KevTrem said:
Wonder if its something about the Heli that means the 1107 doesn't work well with it? Anyways at least you have your problem fixed before it cost you an engine.
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Probably a constant rpm at 12 or 13k with the only change being the load applied if I had to guess.
 
KevTrem said:
Wonder if its something about the Heli that means the 1107 doesn't work well with it? Anyways at least you have your problem fixed before it cost you an engine.
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Theres no difference between the two, besides the larger venturi in the 1107. Both take the same kits, same metering spring, diaphragms etc. Something is wrong with the carb. Which is what we've been pointing to for most of this thread.
I have heard back from obr on basic carb settings, they supply their engines with the 990 from the factory. The instruction sheets to tune and break in the engine do not mention the governor, however I was advised that I should be disabled until the second tank of fuel at minimum.

I've also conducted enough research to say, the governor works how I said it does. You set your target rpm and it maintains it. Period. The govenor via the throttle servo maintains the set rpm. You can take target rpm from either the engine or rotor. It seems gassers tend to use engine rpm and do the gearing math for rotor speed. Either way the govenor doesn't care. Your throttle curve dictates when the govenor kicks in, and seems you can have multiple curves depending on the radio.
Any way glad you got it sorted.
 
sm1nts2escape said:
Thank you for that and I think we can agree to disagree partly on the governor tuning part. Also, I want to apologize for coming back a little stronger than was needed. I had a bad day and should have let most of it go and that is on me. Please accept my apology. Now for some news. I took the heli out yesterday primed the carb first then couldn't get it started. After richening up the low speed I got it started and got massive backpressure through my clunk which created a foaming tank and then my primer bulb filled with air. After I got the air out of the primer bulb the engine died from going rich. I leaned it back out and it seemed fine on the ground and fourstroking slightly with a touch of smoke at idle like I like. After take off as soon as I put it under load the engine was leaning out much more drastically than before to the point my governor wouldn't hold it anymore (overshooting rpms after coming off load) and I was hitting throttle hold to land it and let the engine smooth out/cool off. No matter what I couldn't tune it out so I completely redid my vent line at the field and it had no change at all to the tune so I took the heli home and inspected my carb. I found an airleak on both of my 1107 carbs in the exact same spot plus a couple specks of dirt but nothing more. I am wondering if when the engine is pulling a hard vacuum air is rushing through here and messing with my tune when doing those maneuvers that put heavy load on the engine/vacuum on the carb. I have a 990 that is being delivered today along with some new gaskets so I can see if the 990 has the same leak and if it behaves the same although I doubt it will as I said before I have some friends running them without issue and my friends that are running the 1107 had the same issue in flight as I am having. Also in regards to the comment about large scale flight I figured you guys would have done more testing on this carb then them so came here first. Sorry again.






I've had many and have built over 40 cars now. From modified imports like FD rx7s to souped up hotrods. My favorite out of all of them was my 85 Chevy shortbed with a built 406/th400 running a Holley Truck Avenger 770 Steel bodied carb. The new ones are aluminum to save weight/money.

Click to expand...

So looks like we did not need 15% more fuel we actually needed a lot less unwanted air ?



5atcms.webp
 
Polar_Bus said:
So looks like we did not need 15% more fuel we actually needed a lot less unwanted air ?
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Ha! No everyone else that didn't listen about the 1107 are finally going to the 990 now after having the same issue (going lean). Btw I am getting ready to see what this thing is really capable of. I hear this pipe adds 36% more power.

 
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