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Old 03-09-2003, 01:31 PM   #1
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Default HELP! Break-in/Engine Problems with HPI MT 4x4 Kit!

Hi,

I just finished building my HPI Nitro MT 4x4 kit yesterday, and I was ready to start the break in. When I started the engine, however, the wheels began rotating on idle at high speeds, and it just continued to go up. So I stopped the engine, and I readjusted the idle screw... I tried to pull it almost all the way out, and then I tried to tighten it almost all the way in, stopping it at various points to see if it affected it in any way.... That didn't work, though. So I checked the carb opening and it was at around 1-1.5mm at idle.. The servos seemed to work fine as well..

I got to the clutch again, and saw that they were put on the wrong way, so I fixed them according to the manual's instructions.. I thought this would solve the problem.

I tried running it again today... It was a bit slower, but the wheels still rotate at high speeds; as far as I know, this shouldnt happen..

Any tips/help greatly appriciated,

Thx.
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Old 03-09-2003, 04:04 PM   #2
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Check your throttle trim. It could be a problem when they manufactured the Transmitter. They couldve set the initial trim too high. Contact HPI, im sure they will help or even replace the broken parts for free.
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Old 03-09-2003, 04:07 PM   #3
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i might be set to lean

it could be the idle

or it could be the clutch
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Old 03-09-2003, 04:13 PM   #4
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i think the idle opening is too large

the carb is only like 4 or 5mm right

if the carb is 4.5 and idle is 1.5 your at 1/3 throttle

would the car drive away at idle?

a little drag brake could help

the idle screw should be though of as a stopper

if the servo isnt pushing on the spring on the linkage some it will not fully close the throttle
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Old 03-09-2003, 04:13 PM   #5
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Quote:
Originally posted by jason102276
i might be set to lean

it could be the idle

or it could be the clutch
Okay--

I set the needle valve to three turns like it says to, and I tried to fool around with the idle... What settings do you suggest? How far out should the idle be? (Btw, do you turn it clockwise to increase RPM or to decrease RPM?). As far as the clutch, I just double checked it today and it looks right (just like in HPI's picture)... Hopefully, there's nothing wrong with that.

Thanks a lot for your help!
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Old 03-09-2003, 05:47 PM   #6
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well going fast at break in isn't good but when i first started mine the (RTR version since it was my first RC vehicle) the engine reved way up also and the wheels spun like mad. but after some fiddleing and a few days it ran near idle. At least on mine to make it really idle and with the air/fuel needle set to the books suggestion, the throttle opening has to be under 1mm. if it stalls under then get as close as you can to 1mm
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Old 03-10-2003, 09:03 AM   #7
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i would start it and turn idle screw counter-clockwise untill it slowed down to normal idle

make sure the radio pushes the throttle closed when your are adjusting or what will happen is it wont slow idle and then if you set needle to low and use brakes it will kill the engine

i would turn radio trim negative some start car put the wheels on the ground and hold it in place while you adjust the idle needle untill the clutch bell stops spinning and car isnt trying to drive away then it should be easy for you to fine tune
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Old 03-10-2003, 02:20 PM   #8
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On the stock 15fe the idle should be at 1mm open. The factory settings (3 turns open) should be used as a guide, but you may have to go a little richer, or leaner depending on weather, and even the fuel you use to break in the engine. The wheels will turn occationally during breakin, this is because there is no load on the wheels. Try turning down your idle to 1 mm and see what happens.
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Old 03-10-2003, 02:37 PM   #9
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Quote:
Originally posted by jason102276
i think the idle opening is too large

the carb is only like 4 or 5mm right

if the carb is 4.5 and idle is 1.5 your at 1/3 throttle

would the car drive away at idle?

a little drag brake could help

the idle screw should be though of as a stopper

if the servo isnt pushing on the spring on the linkage some it will not fully close the throttle
Hmmm. I wouldnt run it with drag brakes during break in.
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