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Hobao hyper 21 3-port

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Jarreth_22

Jarreth_22

RC Newbie
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Hi all I have a Hobao hyper 7 tq with the 3-port 21 turbo engine and I’m having some trouble with excessive fuel spitting from the exhaust at idle along with when I open the throttle up from idle it bogs down and stumbles and sometimes stalls (it has a brand new glow plug and new fuel lines, fresh nitro fuel)? Any idea on what could be the problem would be greatly appreciated
 
Jarreth_22 said:
I’m using glo-max cb 20% nitro and the car is second hand
Click to expand...
What oil percentage? I shoot for 8-10% oil. 20% nitro is good. I was concerned you were running Traxxas fuel, it is known to be high in oil content and hit n miss depending on the batch.
Watch that video in its entirety, do not skip over anything. It may be necessary to watch some parts a few times. Use your gift of hearing to tune that engine. Set the idle gap like the video shows, which gives you only 2 needles to be tuning on.
If it idles on its own but chokes out when you give it throttle it could be lean, or it could be super rich. It is hard for me to troubleshoot because I can't see or hear it.
 
Jarreth_22 said:
I’m using glo-max cb 20% nitro and the car is second hand
Click to expand...
Is the fuel second hand too?
Fuel can go bad so whenever someone struggles, new fuel from a sealed bottle is #1. Save the old stuff for after its running correctly if you want to.

Your tune... it sounds like you are stuck on keeping your motor at 'factory settings' and then it doesn't run correctly.
If so, do not he afraid to tune away from those settings in order to make your engine run right.
Your tune can change from hour to hour or day to day.
Factory tune is a base line and is very helpful for when you've gone so far out of adjust, theres no way your engine could start.... factory settings are like a reset button.

Make sure your fuel lines are soft, not cracked. (They are cheap and take 5 mins to replace. I'd just replace them)
Is your aircleaner new, clean and oiled?
Fresh, CORRECT, brand name glowplug?
Is your fuel tank sealed? No air leaks if you blow into the fuel line WHEN THE TANK IS EMPTY!!!😉

Where its second hand, its best to start right at the begining and check ALL the free basics.

I would buy orings (and AE green slime) for the carb and replace those just so you know its done too.

Make sure the sringer in your exhaust is facing down so the pipe will drain.
Make sure you drain all the oil thats in there and be sure you haven't got a blockage in the pipe.
 
TeknoJ said:
What oil percentage? I shoot for 8-10% oil. 20% nitro is good. I was concerned you were running Traxxas fuel, it is known to be high in oil content and hit n miss depending on the batch.
Watch that video in its entirety, do not skip over anything. It may be necessary to watch some parts a few times. Use your gift of hearing to tune that engine. Set the idle gap like the video shows, which gives you only 2 needles to be tuning on.
If it idles on its own but chokes out when you give it throttle it could be lean, or it could be super rich. It is hard for me to troubleshoot because I can't see or hear it.
Click to expand...
No worries thankyou for you’re help
 
CertifiedMike said:
Is the fuel second hand too?
Fuel can go bad so whenever someone struggles, new fuel from a sealed bottle is #1. Save the old stuff for after its running correctly if you want to.

Your tune... it sounds like you are stuck on keeping your motor at 'factory settings' and then it doesn't run correctly.
If so, do not he afraid to tune away from those settings in order to make your engine run right.
Your tune can change from hour to hour or day to day.
Factory tune is a base line and is very helpful for when you've gone so far out of adjust, theres no way your engine could start.... factory settings are like a reset button.

Make sure your fuel lines are soft, not cracked. (They are cheap and take 5 mins to replace. I'd just replace them)
Is your aircleaner new, clean and oiled?
Fresh, CORRECT, brand name glowplug?
Is your fuel tank sealed? No air leaks if you blow into the fuel line WHEN THE TANK IS EMPTY!!!😉

Where its second hand, its best to start right at the begining and check ALL the free basics.

I would buy orings (and AE green slime) for the carb and replace those just so you know its done too.

Make sure the sringer in your exhaust is facing down so the pipe will drain.
Make sure you drain all the oil thats in there and be sure you haven't got a blockage in the pipe.
Click to expand...
Thanks the fuel is brand new. When it sits at idle it spits out a fair bit of fuel from the exhaust
 
It is supposed to be spitting some oil. I can't say what is 'too much' sitting on my phone... the oil spitting out is the oil that is keeping your engine running and lubed. There is no oil pan, no reservoir to lube the rotating parts in nitro so it ALL comes from the fuel.

Have you watched the tuning videos to help you get a visual idea of what is 'ok' and what is not?

This 'problem' that you're having sounds like a tuning problem to me if at all.

You might need to dial in your carb settings if its bogging down. Otherwise, I would be running the car and monitoring the engine temps closely with a heat temp gun.

If the enging is getting hot, stop and give it a bit more fuel. Otherwise, lean the carb out until its tunning right and doesn't bog when you whack the throttle.

You want to have a steady stream of white smoke when you're running. Not to fog out the parking lot you're in, just a stream that lets you know there is oil lubing your engine as its being run.

If there is no smoke (oil), something is wrong.

Tuning is a regular part of nitro. Learning how to get your engine running correctly will get you better performance and longer life out of your nitro engine.

Use a temp gun, write things diwn until you know what you're doing.

As far as adjysting the carb...
Adjust in 'turns' so you can 'undo' what you did easily if you don't like it.
Turn the head of the screw in 90° intevals....
1/4 turn, 1/2 turn...
If that adjust made it worse, its easy to remember 1/4 turns....
(Its not rocket science. You don't need to record each turn of the screw. )

Nitro is pretty easy and fun once you 'get it'. 😎
 
Thanks I think I’ve got the tune just about right but for some reason it idles very up and down and when I pulled the brake on it seemed to rev out?
 
Have you adjusted the endpoints on your radio?
I would start there.
Verify your linkages are adjusted correctly and that everything is tight. No slack in rod ends, no binding? The carb isn't wiggling or twisting at all?
Make sure the motor itself is still tight too.
Vibration on nitro means you need to recheck your hardware and ALWAYS use blue locktite!

I'm not sure of other reasons why you'd have rpm issues on braking. 🤔
 

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