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| Nitro RC Car and Truck Discussion Discuss nitro RC vehicles |
Topic Review (Newest First)
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| 07-06-2016 07:03 AM | ||
| Cougar429 |
Re: Issues with priming the engine!!?? If the flooding is happening at low throttle you likely have the Low Speed needle, (LS) too rich. Without knowing your throttle position at the time, the running up to full or acceleration could be caused by a lean condition. Look at it this way: The LS controls minimum fuel flow, while the HS controls max. That may sound confusing, but to simplify, the LS needle, normally buried in the center of the rotating throttle bore and accessed through the center of the throttle arm. Also, the normal setting to get you in range would have the end of the adjustable needle even with the end of the barrel itself, NOT the end of a cap or plate that would be part of the throttle arm assembly. That and setting the HS needle to the 1 3/4 out may get you going at least. NOTE: These are what I would start on a larger engine for aircraft or helis. If someone else has more accurate settings or there are instructions with different specs go with them. These needles mostly work by the following rules: The LS needle controls mixture all the way up to approx 3/4 throttle, the ratio physically set by the needle tape and the contour of the groove cut into the barrel that moves it in and out with rotation. The High Speed needle, (HS) only takes over above 3/4 throttle all the way to full and sets mixture for full throttle/full load conditions. Believe it or not, that setting is usually the easiest as any changes you make are immediately noticeable. That is why I try to work with that first if I can at least start. Once I have slightly rich of peak RPM I slowly back the throttle down and make adjustments to the LS to tweak the mixture as I drop the RPM. The aim is for a stable idle and good transition. If you can maintain a sustained idle, but it stumbles before picking up on throttle advance you are slightly too rich. If it dies you are too lean. All this is if you have an engine in good condition and a healthy glow plug. If you cannot keep it running with heat removed regardless, replace the plug and try again. Note that dying with heat removed is also an indication of a rich condition so you may have to keep at it if this still occurs with the new plug. For starting you should only require a small amount of open throttle bore showing. If that floods the engine screw the LS needle in rather than try with any other change or setting. |
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| 07-05-2016 07:41 PM | ||
| davidmc36 |
Re: Issues with priming the engine!!?? If it is flooded, take the fuel line off the carb and then pull it over, don't suck more fuel in. |
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| 07-05-2016 07:25 PM | ||
| Sago |
The problem was that even with the factory setting for HS and LS she had no airflow. I took her apart cleaned her up and re adjusted the throttle linkage and made sure there was flow throw fuel inlet. And then I had her start with one pull and run, but for about 3 seconds. The carb was running way too rich and she went almost full throttle for about 3 seconds. Stopped her and re adjusted the carb and the throttle linkage and I couldn't get her to start, kept hydrolocking her. Tested the glow plug re adjusted fuel flow, still couldnt get it to start and then I broke the pull start. When she was flooded I pulled the glow plug out and pulled the pullstart and she was pulling in fuel. Any ideas? Cheers |
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| 07-05-2016 11:39 AM | ||
| davidmc36 |
Re: Issues with priming the engine!!?? Quote:
Soak in fuel or IPA for a while to loosen it up. Warming with a heat gun sometimes softens it up a bit too that you might be able to pull the carb. |
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| 07-05-2016 08:51 AM | ||
| Sago | Haven't had much time to work on the truck, but I quickly put a new spare line in the carb and blew in. And no flow what so ever. I'm thinking of taking the carb out and fixing it that way or throw in another carb (I have 2 spares) but I'm having difficulty removing it as well. She won't budge... | |
| 07-04-2016 08:44 PM | ||
| Cougar429 |
Re: Issues with priming the engine!!?? With the age I would think it highly likely the carb inlet and/or needle is plugged with congealed lube. Pull the line as Floyd recommended, put a spare piece of fuel line on and blow. Even at low throttle you should get some indication of flow, increasing as the throttle is opened. If nothing unscrew the needle and try and flush with fresh fuel. With the throttle full open place your finger over the now open end where the needle unscrewed and repeat the process till you see fuel enter the carb bore through the distribution tube. Once done thread the HS needle back in and try again. Not sure if that would follow the standard, but I find a good place to start is with the HS needle backed out 1 3/4 turns from lightly bottomed. |
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| 07-04-2016 08:32 PM | ||
| floyd |
Re: Issues with priming the engine!!?? Take the fuel line off the carb and you should be able to blow fuel through the line then. That will tell you if the carb is the place to look. If you open the high speed needle and the throttle you should be able to blow fuel through it or air through it. Cheers Floyd |
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| 07-04-2016 08:09 PM | ||
| Sago | Well that didn't work now did it. | |
| 07-04-2016 08:07 PM | ||
| Sago | Sorry. Here are the pics | |
| 07-04-2016 08:06 PM | ||
| Sago |
Issues with priming the engine!!?? Im new to nitros. So this is a 2009 Traxxas Revo 3.3 but she has a random 2.5 pull start engine in her. Brand new glow plug in. But I can't prime the engine. So I've tried priming the fuel line to the carb by blowing air in from the exhaust line leading to the top of the gas tank, no fuel travels down the line to the carb but instead the pressure in he tank causes fuel to come up the exhaust line. Any suggestions? |
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