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Need helo with valve needle settings

Need helo with valve needle settings

Old 03-02-2012, 05:11 PM
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Default Need helo with valve needle settings

I have a new 1/8 OFNA Hyper Sprint car and it was not set correctly from the factory. So I started messing around with them. I can get it to run but it idles way too high. I have to hold it or it will take off. I can get it to crank and then it will idle high and then idle down like it should be but then it cuts off. I am completely lost! Any help is thankful.
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Old 03-02-2012, 05:53 PM
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Default If you drop the idle it stalls?

Originally Posted by Miketuck12
I have a new 1/8 OFNA Hyper Sprint car and it was not set correctly from the factory. So I started messing around with them. I can get it to run but it idles way too high. I have to hold it or it will take off. I can get it to crank and then it will idle high and then idle down like it should be but then it cuts off. I am completely lost! Any help is thankful.
If you cant turn over the engine with your thumb on the flywheel, it isn't run in yet. If you can.. first get it to idle correctly and have a good bottom mixture. If you can't then it's doing what it should be, keep the top rich, don;t throttle it and let it run in. Depending on the carby, reducing idle gap can richen the LSN low speed mix and it cools engine down and seizes becuase it's still too tight. There's heaps of run in document sticky threads to guide you.

Oh, and.. 1mm idle gap is a great place to start.
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Old 03-02-2012, 06:56 PM
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How do you tell if it is set at 1mm? I have tried all kinds of combinations. Yes I can turn the flywheel. If I prime it will run for a few seconds and then die. If I don 't prime it doesn't seem to want to start. it's like its not getting any gas? but earlier today when i could get it to start and run the it was at a really high idle and i could stick my hand at the end of the exhaust for about 2 seconds and i had what seemed to me to be fuel like it was getting way too much. I am really new to this, this is my first nitro car.
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Old 03-02-2012, 06:57 PM
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the motor is the Mach28 that comes with the OFNA RTR. All i had to get was batteries and Fuel.
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Old 03-02-2012, 07:59 PM
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I am learning very quickly on needle adjustments for High and Low End. I didn't know a lot of what you were talking about in that thread but a little research did great! I still can't find the baseline setup for the OFNA Hyper Sprint Car Mach.28 Engine that comes with it. I did find this:
http://www.ofna.com/guide-tune-basics.php
But the one that looks like mine is the Hyper Engines - 21. Guess I'll have to call Tech Support cause I think I adjusted the Mid-Range Needle
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Old 03-04-2012, 04:22 PM
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Originally Posted by Miketuck12
I am learning very quickly on needle adjustments for High and Low End. I didn't know a lot of what you were talking about in that thread but a little research did great! I still can't find the baseline setup for the OFNA Hyper Sprint Car Mach.28 Engine that comes with it. I did find this:
But the one that looks like mine is the Hyper Engines - 21. Guess I'll have to call Tech Support cause I think I adjusted the Mid-Range Needle
I found out that the factory setting is HSN=3.5 turns out from closed and the LSN=2 turns out from closed.So turn the needle clockwise until you feel it stop...do not force it you WILL damage the needles.One turn is a 360degree turn.Set your carb at 1mm=about 1/16 of an inch.This should set you straight.Now for tuning, start making long runs so you can tune the HSN, keep leaning this 1hour increments until you get no more gain and then richen it back up 2 hours roughly.Make sure you are still getting smoke out of your pipe.Now lets do your LSN,in 1 hour increments again start leaning it out until you get no more gain. then check your temp while it sits...if the temp keeps going down while you sit you are pretty close.The more you use the engine and listen to it you'll catch right on.
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Old 03-05-2012, 07:52 AM
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Originally Posted by are yew mad yet
I found out that the factory setting is HSN=3.5 turns out from closed and the LSN=2 turns out from closed.So turn the needle clockwise until you feel it stop...do not force it you WILL damage the needles.One turn is a 360degree turn.Set your carb at 1mm=about 1/16 of an inch.This should set you straight.Now for tuning, start making long runs so you can tune the HSN, keep leaning this 1hour increments until you get no more gain and then richen it back up 2 hours roughly.Make sure you are still getting smoke out of your pipe.Now lets do your LSN,in 1 hour increments again start leaning it out until you get no more gain. then check your temp while it sits...if the temp keeps going down while you sit you are pretty close.The more you use the engine and listen to it you'll catch right on.
Thanks!! I really appreciate all the help
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Old 03-13-2012, 06:30 PM
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okay. i had it idling right and was making sure everything was working properly and then the radio went out. So after battling back and forth with customer support (Dave) they sent me the wrong radio with the brand new RTR version. So i get the new radio today and it works just fine. Now it will not start again. i just wanna throw this thing in the dumpster. The glow plug and igniter and everything seems to be working like it is supposed to. As long as I am holding the throttle all the way down when i pull the pull starter it will stay running but as soon as I let go of the throttle on the radio it dies. I am lost yet again with this car
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Old 03-13-2012, 06:31 PM
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and how do you get a 1MM idle gap? I'm not understanding that
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Old 03-13-2012, 10:47 PM
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Originally Posted by Miketuck12
and how do you get a 1MM idle gap? I'm not understanding that
Remove the air filter, remove the choke and get a metric ruler. Set idle screw until 1mm gap in carby. Might need a little bigger for a larger engine but for the most part it's going to start when lean more so when rich

The bottom end tuning is the most critical aspect of tuning. The mixture, at the bottom or idle is key as it's normally a little rich so it's hard to tune and you dont need other contributing variables (fuel pressure/air leaks/bad plugs/no compression/bad servo trim ) complicating things when trying to establish where the best idle mix is.

Why is it so important? it's critical when the engine is coming off FULL RPM where it has lean out the crank of all the residual fuel.

So, when you back off from full throttle and you engine STAYS high idle, that's the TRUE idle. If the Low Speed Needle LSN is rich and the IDLE GAp too large this creates a fake idle.

What are you trying to establish? - You are trying to establish a point on the bottom mixture where there is enough fuel to lubricate and cool but not too much as to require more AIR.

How do I find it... To find this bottm mix sweet spot your engine needs to be warmed up and at idle. NO throttle required and you could even richen up the HSN top needle by a whole turn out to ensure you are getting enough fuel pressure. (Note: It's a slow process waiting for a crank to clear of fuel.. be patient)

With a given known 1mm idle gap as mentioned, it shouldnt be hard to find where the bottom needle sets a good mixture for the gap the IDLE screw made. The engine will increase in revs slightly when you are leaning it out. And it will stall if too rich.

Now what... Once you've found this spot, then it's a matter of chasing the idle screw with the bottom mix any time you change it. So if the idle is too high and you make the gap smaller, you are in effect richening up the engine as well.

So chase your idle gap with the LSN if you have a good bottom mixture but too high an idle. If you come off full throttle and the idle drops nicely then you are in the ball park.

The top needle is still rich... As you lean it, it will effect the bottom tuning to a degree, leaning it up as to reducing overall fuel pressure will cause all sorts of problems. for the most part, do it on track after a good three-four laps and listen well and smell for burning...I am not a fan of temp tuning..
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Old 03-13-2012, 10:58 PM
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Default They will all start cold!

Originally Posted by Miketuck12
okay. i had it idling right and was making sure everything was working properly and then the radio went out. So after battling back and forth with customer support (Dave) they sent me the wrong radio with the brand new RTR version. So i get the new radio today and it works just fine. Now it will not start again. i just wanna throw this thing in the dumpster. The glow plug and igniter and everything seems to be working like it is supposed to. As long as I am holding the throttle all the way down when i pull the pull starter it will stay running but as soon as I let go of the throttle on the radio it dies. I am lost yet again with this car
Hey... I was once like that 30 years ago with a Cox single needle model airplane engine... Ive since realised they "ALL" start.. ok!

I've bored out a liner with a dremel to fit a larger piston, fired her up and she purred like a kitten... for all of 2 minutes. So if your engine is "khapuut" it will never the less start when cold.

So check glow starter and plug. If fuel is pouring out, TOO MUCH IDLE!!!
See other post, pushed an idle screw and carby cylinder into a bottom needle ... ouch. Pull the plug out and turn it over, if it's a shower, you're flooded, if you cant smell fuel... you've closed the taps!
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Old 03-14-2012, 11:58 AM
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Originally Posted by blis
Hey... I was once like that 30 years ago with a Cox single needle model airplane engine... Ive since realised they "ALL" start.. ok!

I've bored out a liner with a dremel to fit a larger piston, fired her up and she purred like a kitten... for all of 2 minutes. So if your engine is "khapuut" it will never the less start when cold.

So check glow starter and plug. If fuel is pouring out, TOO MUCH IDLE!!!
See other post, pushed an idle screw and carby cylinder into a bottom needle ... ouch. Pull the plug out and turn it over, if it's a shower, you're flooded, if you cant smell fuel... you've closed the taps!
Thanks for all the help!! No I am facing yet another issue. I got all the needles set right. When it started earlier it started and Idled right off the bat like it should. However as soon as the prime fuel is done then it stops. I tried taking the Overflow fuel has that goes to the exhaust off and blowing through it to prime it, and I can't blow through it. It is extremely hard. And I took off all of the lines and tank. Made sure the Filter was clean, made sure all the lines were not stopped up, emptied the tank and made sure all the connected were cleared of anything. Even when I am priming it, No fuel is moving anywhere. What should i try next to figure out while the fuel isn't moving? And I have tried blowing in the line and also holding my finger over the exhaust port and pulling the pull start a little bit. Nothing seems to work.
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Old 03-15-2012, 05:50 AM
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Originally Posted by Miketuck12
Thanks for all the help!! No I am facing yet another issue. I got all the needles set right. When it started earlier it started and Idled right off the bat like it should. However as soon as the prime fuel is done then it stops. I tried taking the Overflow fuel has that goes to the exhaust off and blowing through it to prime it, and I can't blow through it. It is extremely hard. And I took off all of the lines and tank. Made sure the Filter was clean, made sure all the lines were not stopped up, emptied the tank and made sure all the connected were cleared of anything. Even when I am priming it, No fuel is moving anywhere. What should i try next to figure out while the fuel isn't moving? And I have tried blowing in the line and also holding my finger over the exhaust port and pulling the pull start a little bit. Nothing seems to work.

With car shut down, unwind the top needle 1 turn, remove the air filter, the fuel pressure fuel line from pipe, open the carby to full throttle and blow some fuel pressure into the tank like you did before. you should see fuel enter the carby.

Seems the carby is blocked, either by the needles or the jets are blocked. It's not too hard to disassemble a carby but the jets are pressed. Just note you need to unwind the idle screw to allow the carby cylinder to come out if pulling apart completely and align the groove when putting it back idle screw back in.


The fuel line to pipe is a pressure line, not an overflow.
However as soon as the prime fuel is done then it stops. After it's started?If flooded remove glow plug, crank it over and clear the engine of fuel.. try again
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Old 03-15-2012, 06:03 AM
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Originally Posted by blis
With car shut down, unwind the top needle 1 turn, remove the air filter, the fuel pressure fuel line from pipe, open the carby to full throttle and blow some fuel pressure into the tank like you did before. you should see fuel enter the carby.

Seems the carby is blocked, either by the needles or the jets are blocked. It's not too hard to disassemble a carby but the jets are pressed. Just note you need to unwind the idle screw to allow the carby cylinder to come out if pulling apart completely and align the groove when putting it back idle screw back in.


PS: The fuel line to pipe is a pressure line, not an overflow.
Okay I will try that here in a little bit when I get the chance. I have taken the motor and everything off of the car. took the clutch shoes and everything else off. I noticed that on the mid range needle there are 4 little holes around the inside part. Do you think that need to be lined up exactly with where the fuel comes in? and yea i knew the fuel line wasn't an overflow, but i didn't know what it was called and everyone knows what an overflow hose is if they are a car person so I knew y'll would know what i was talking about lol. And OFNA wants me to send my motor to them so they can bench test it? He said "Sounds like the low speed needle was set too far in. The needle should not be closed and adjusted. If the needle was at 2 turns from closed chances are it caught the mid range(nozzle) and moved. The best thing to do at this time is it remove the engine and send it in for inspection and "bench Testing"."
He told me that becauase i noticed a couple of time that when i would agjust the LSN that the mid range needle would not be flush anymore.
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Old 03-15-2012, 01:56 PM
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Okay. I have it all back together. Do i need to lube the carb with anything? Any special oil or something? It is getting fuel now. Now I am back to the first problem off not wanting to start. When the glow plug went out that they sent me with it i bought some more. But the ones that they gave me were medium-hot. The one they sent me with the engine was a hot. Does that make any difference? the glow plug and igniter are working like they should. I put the glow plug inside the igniter with it off of the car and it glows.
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