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-   -   Pressure loss problem, open to suggestions (http://www.rcuniverse.com/forum/rc-nitro-stadium-trucks-243/10909201-pressure-loss-problem-open-suggestions.html)

Dlolpics 01-14-2012 07:57 PM

Pressure loss problem, open to suggestions
<div>So I'm having a problem, I think it is a pressure loss problem.</div><div></div><div>Basically I notice that sometimes (not always, and not all the time) but fuel is not getting to my carb. I don't know how the pressure is being lost. At first I thought it is a leak of some sort anywhere from the exhaust to the tank. But now that I'm thinking about it, to figure this out I took the fuel line off of the carb and started to try and prime the engine and after a few pulls the fuel started spilling out.</div><div></div><div>So maybe there is a clog of some sort in my carb?</div><div></div><div>Only thing that makes me really confused is once I give a little trim (little bit more then when "nothing is wrong" and I'm starting the engine) and the engine gets going there isn't a problem for a while.</div><div></div><div>Only reason why I think it isn't just a priming problem (like I didn't prime the engine when trying to start) is the problem seems to happen while running. I'll just randomly be bashing around and the engine will die.</div><div></div><div>After walking to my buggy and trying to restart It, I feel that there is no fuel in the engine, so I usually check the tank to see if I'm out and most of the time I still have fuel, usually 1/4 or more of a 75cc tank. So I've come to the conclusion the pressure is lost some where and doesn't push the fuel through. I've also died on a few WOT. I doubt I'm running lean, but I guess this might of been that issues. I really doubt it though.</div><div></div><div>This whole problem has only happened around 3 or 4 times total but even once is enough to be a problem.</div><div></div><div>I've just replaced all my fuel lines and I have no kinks or anything.</div><div></div><div>This whole thing leads up to my main question. Can I take apart my exhaust and clean it out.</div><div>I've only ran about half a gallon through my buggy and I've been running very rich, I'm thinking it might be clogged a little bit, but I'm not sure. I don't see why I couldn't take it apart and clean it logically speaking but everything I see says "TUNED" so I wasn't sure if I could like un-tune it or something?</div><div></div><div></div><div></div><div>Anyone have anything/advice?</div><div></div>Thanks for reading.

quietnas1 01-15-2012 02:05 PM

RE: Pressure loss problem, open to suggestions
Make sure your not running to lean. Try and richen the hsn by turning it counter clock wise. If you see fuel coming out of the exhaust then your running to rich. Try turning the hsn clock wise to lean it out. Make sure you do your turns in 1/8 increments and then test.

joshreynolds777 01-22-2012 05:57 PM

RE: Pressure loss problem, open to suggestions
Keep an eye on your temps. If you dont have a temp gun, get one. ($20) They act up around 280 plus. sometimes get hard to start over 300.
temps are fine then Try a new Glow Plug. but like the guy above, Im leaning toward lean and high temps. Look for plenty of blue smoke at high throttle

JoesGT2 09-05-2012 10:12 PM

RE: Pressure loss problem, open to suggestions
i would be looking for a exhaust leak. if , possibly exhaust manifold gasket. it might be fine at idle but at higher rpms it could cause a problem. either way it would start to run lean n give tunning problems.

1QwkSport2.5r 09-15-2012 07:26 AM

RE: Pressure loss problem, open to suggestions
Exhaust pressure is only going to push fuel at higher RPM. At idle, there is very little, if any, muffler pressure forcing fuel into the carb. If you're having a hard time getting fuel to the carb while trying to start the engine, Either the carb is plugged with something (fuel filter installed? dirty?), the idle gap is too small and/or the idle mixture needle is too lean. I suggest first opening the idle mixture needle some and see if the problem goes away. Too narrow of an idle gap will cause the idle mixture to be lean. Opening the idle needle OR opening the idle gap will richen the mixture and allow fuel to come through.

If you can get fuel to the carb and get it started okay, and later on it just dies with no fuel in the feed line to the carburetor, perhaps the tank is cracked or the lid isnt sealing properly. Most often, unless the leak is severe, any leaks in the exhaust system will not effect the pressure to the tank that much. Ask the airplane guys that have aluminum mufflers that bolt on to the engine metal to metal with no gasket! They all weep a little oil while running, with no ill effects on engine operation.

125cchyperman 11-13-2012 06:07 PM

RE: Pressure loss problem, open to suggestions
I doubt it is an exhaust leak as you do not need to run a pressure line form your gas tank to your exhaust at all. Ive been doing that for year, so did adam drake. Just need to run it a little richer thats all. I doubt it's a temp thing, as if was a temp thing it probably would have locked up on you already. Take the glow plug out and look at it. If the plus a white ash color then your way lean. You want it to be a nice golden brown color almost like honey. As others have said you may be running lean, but DO NOT rely on blue smoke as an indicator. As fuels with more oil content tend to smoke more then fuels with less oil content. Also engine temps arent always the best as some engine like to run hotter then others, they all tend to have there own personality. The glow plug is a much better way to tell if your lean or rich. You can (if your experienced enough) listen to the tone of the engine, you can tune yourself in and hear if the engine's running right or not.


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