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Old 11-06-2008, 08:51 AM   #1
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Default Newbee Engine help!!

To start out -I have a Losi eight buggy, running a radical 621t engine with a JP-4 pipe.
I have a couple of issues. I finally got the engine to start up after a new state box that can turn the motor, now once the engine is running - the wheels are moving and setting it down it slowly moves. then when I apply the brake the engine shuts down. I have the low and high speed needles set according to the distributer.
Like the thread title states - I am new to nitro and do not want to ruin the engine before I get to race it.

Thanks in advance.
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Old 11-06-2008, 09:07 AM   #2
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new engines require break in. As you stated.. the motor is very tight when new.. you needed another box in order to get it to crank..

First the first tank.. you may want to let the motor just heat up and such on the box.. dont worry bout puttin it on the ground.. then after that first tank.. let the engine cool down.. be sure to turn the flywheel, so the piston is at the bottom of the stroke.. you will know this, as, when the piston is at top.. its very hard to turn..

Let the engine cool down completly.. next.. get you a hair dryer, heat the motor up, crank it, and just put around for a little.. understand, the engine is in a very rich state.. and will be hard to run in this state.. so.. be ready to be restarting alot.. just drive the car in circles.. go left circle, right circle.. just blippin the throttle.. after this 2nd tank.. same apply.. bottom out the motor.. and let cool completly..

3rd tank is when you can start leaning a little bit..

if you would like.. pm me with any questijons, or concerns, we may even be able to chat on the phone, might be easier..

Take care, and just follow those instructions..

Daniel Grobe
Team Kyosho
Daniel Grobe
Proline Racing / RC America / Xray
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Old 11-06-2008, 09:07 AM   #3
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Your idle speed is too high and there may be something wrong with your linkage. Make sure when setting the linkage, you set it under full breaking so that it doesn't close the carb all the way. That's likely what is happening.

Try closing your idle to the point that it stalls, then open it just a bit.
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Old 11-06-2008, 10:36 AM   #4
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If you're running the stock Losi shoes and springs that came with the kit your car shouldn't creep at all at idle. Inclined to agree with what Semple said, your idle is probably too high. If not, you may need to look at the clutch. Make sure there's a small amount of play b/w the clutch bell and the screw on the end, the bell should spin freely. Every engine is different. One of mine shims jut like the manual show, one of them won't work unless I take all the shims out.

Disconnect the linkage. When the carb is in the closed position, the throttle gap should be b/w 0.5 to 1 mm (about the thickness of a credit card). Check your engine manual, it might tell you where to set it for that engine. Set and then leave it alone during break in.

After you do that, readjust the linkage so that when your radio is at neutral the carb is all the way back to closed. You might have to loosen some of the linkage collars to get it there, just slide them where they need to be and re-tighten. If you don't have it already, download the throttle linkage addendum from the Losi site. On the 8ight you DO NOT WANT TO HAVE IT PULL FULL THROTTLE! At full throttle there should be a little of the slide still showing, so that you can grab the linkage and pull it out about 1 mm. If you don't, the 8ight will eat your servo. The addendum will show you.

One other thing on the 8ight. You rotate the carb to get the linkage as straight as possible, but be sure you have a 1mm or more gap b/w the linkage and the center diff mount. If you don't, the chassis will flex and the diff mount can hit the carb slide. Happened to me and a couple other people I know, lesson learned. Most of us grind the center diff mount back some so we can straighten the carb but still get the clearance we need. If you go to the 8ight thread there's a pic of my linkage and you can see the mount. I'll bump the thread to the top so it's easy to find.

Grobe gave you one of the many ways to break in an engine, LOL. It will work fine. You want the engine to be rich, but you also need to be able to run it around like he described. If you need to you can lean it a little, but just to where you can keep it running.

A lot to digest, so go slow, and if you have any questions just ask.
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