Loswave

For some reason that I have yet to figure out my truck will die while I'm drivng, although this usualyy only happens when it goes into low idle. I'm not sure why, but when I first start the truck it idles fine, but after getting up to temp, it wants to idle lower, and if I let it for more than a second or two it dies. I have a feeling that it is caused by the same thing that makes it really hard to prime. Whether using the primer button, or doing it the old fasioned way the gas wants to backtrack right down the line when I stop priming. I checked all my lines and none have holes in them, although I plan on replacing them soon anyways, and the tank seems to hold pressure as well as I would expect. Any ideas? I'm out. I thought maybe it was dieing because the LSN was a little rich, although I'm not sure anymore, that still doesn't explain why this thing wont prime well. Thanks.

claudacio

My Feedback: (9)

The primer on the tank is garbage, your best bet would be to rip it out and put a large screw in and seal it up with some goop. Mine worked for a whole day before it started causing me headaches and not working. Another thing is that it sounds like you may be a little rich on the LSN, usually an indicator is a low idle and loading up quick.

You may want to rip the tank off (empty the fuel out) and fill a sink or tub with water, with both fuel line and pressure line attached submerge it in the water while keeping the tops of both lines above the water. Now pinch one side so its sealed and blow in the other. If you see any bubbles, you have an air leak and need to tend to where ever the bubbles are coming out. But like I said above, you sound rich, so an airleak may not be the first thing to look at, but its a possibility if you cant get the engine to hold a tune and you've changed the glow plug and all that.

Loswave

Alright, next time I run I'll lean out a little, if that doesn't work, I'll recheck my lines and tank. Thanks.

kmatlock

Great tip; thanks. I just joined this site after googling to find help with the LST2 that my son and I recently purchased. After spending a great deal of time thus far including replacing a defective transmission server, I think I have the whole tuning thing down fairly well. I have been trying to be careful with regards to temp issues after high speed runs, so I think we're good on that. Also, I followed the mfr's recommendation in testing the low speed needle using the pinch method of the fule line that they recommended. Trouble now is that the darned thing kills every time we brake or turn sharply with any speed. I do notice that we were getting air bubbles in the line between the fuel filter and the carb. Took the filter off and tightened it, but ran out of time that day to go much further. I'll try you're suggestion with the fule tank. Any other ideas?

Loswave

If you have air bubbles in your fuel line then you have a leak in there somwhere, I'd test your tank the way claudacio reccomended, or you can take it out and put soapy water on it, plug one tube and blow in the other, then look for bubbles, same idea, although I like his method better. I take it that your new to nitro R/C's so one golden rule to remeber is to always check the glo plug. If it's fouled it won't work as well anymore and can cause the same problem, and if it's the same plug that came with the truck it could probably use replacing. Most of the time it's a good idea to change out your first plug after you break in and start the tuning process. Hope that helps, and I hope you guys enjoy your truck.

kmatlock

Thanks Loswave for the encouragement. I did change the plug a while back after the first one crapped out. I'm beginning to see the need for some extra ones!!

Loswave

I try to keep 5 or so at hand, but always seem to have 1 at most... I have yet to get the chance to play with my settings again because it's been raining since I posted thie thread, jeez I hate CNY sometimes, mainly when it's rain or it's winter, which is most of the time...

kmatlock

Yeah, well my son and I just got in yesterday from a beautiful weekend of fishing on my foreman's boat at a local island about 20 lies off the coast of SoCal, but sorry about that!! I am going to work on it some more this coming weekend, so I'll let you know what developed. Good luck with the rain....

Loswave

It's still raining... well, it was alright today, but the ground is so wet from the rain I didn't want to risk my electronics... Perhaps tomorrow, I think my bro and I are going to have a tuning run in a parking lot... his savage is really rich all of the sudden, so we'll fix that too. Hope you had a good time fishing, I may be doing some myself this weekend, it's finally time to get the boat going! Hope you get it working, they can be a real pain when you first start, after a few years most problems are a breeze. Not to say it'll take you years to get it working lol.

JSRacer

Loswave, I had the same problem exactly a while back and leaned my LSN quite a bit and had to adjust the idle screw to bring the idle back down a fuzz. Now I have no idle problems and the truck runs great.

Loswave

According to the people I talked to today, it was overheating, so I'm going to just retune it instead of mess with it anymore. Somewhere along the line my tuning must have gone awry...

kmatlock

Hey Loswave, I did the sink testing of our fuel tank the other night. The tank, lines, and filter are tighter than a drum. Any other recommendations from anyone concerning our original problem with this fairly-new truck? The main problem has to do with a constant shut down when hard braking or turning sharply. Is this an idle speed problem? It just seems a little weird that idle RPM would need to be so high. We'll give it a go again tomorrow and see what happens. I know that I was seeing air bubbles in the line between the filter and carb, but now that I tested the tank, lines, and filter, I'm stumped...... []

bauerbach

your sure its trimmed correctly? IE. when you brake does the carb close any?

kmatlock

How do I know whether the carb closes? Do you mean do the engine RPM drop?

JSRacer

Take your air filter off and look down inside the carb and you'll see it's not suppose to close completely. Turn your Tx and Rx on and apply the brake and if your throttle moves and closes the carb at all, your adjustment is out. You'll have to adjust either physically on your throttle linkage or your EPA on your Tx. If this is your problem, let me know and I'll try to guide ya through it.

Loswave

It's come to my attention that this will also happen if the engine overheats, I've found that my engine is fine when I'm on road, but if I'm driving through tall grass, at about half tank, it startes to overheat. When it starts to overheat you get vaporlock in the carborator, which causes not enough fuel to get to the engine, and it will die like you discussed. If you have an infared temp gun check the temp when it starts to want to die, and if it's high, just richen it up a little. You generally want to keep it below 260. If you don't have a temp gun I would highly recommend getting one because they're only about 25 bucks. I tuned my engine on-road, where it stayed cool, but grass and rough terrain put stress on the engine which causes it to heat up more than it would on a smooth surface, so in short, even if it seems good, always check your temperature. I've been at nitros for about 5 years, I should have known better but sometimes we all make stupid mistakes. I just figured I'd point that out, because I thought my temps were spot on, I just never thought to check them again when I was done tuning. I hope it works out for you!

kmatlock

Thanks for the tip. My daughter's boyfriend who is pretty mechanical came by over the long weekend with his new Savage X. We played around with ours. I did take the air filter and look into the carb and adjusted the idle that way as a starting point. We ultimately set everything back to factory settings and fired it up. After adjusting the low end needel much leaner and bringing the idle to an ideal spot, we were able to drive the truck like never before!! I purchased this a couple of months back and my son and I have never been able to have fun with it. Boy, did that change!! We ran the heck out of it off and on over the weekend and this past Tuesday night. Temp is fine: between 205-215. I guess I could lean it out, but I figure it will be better on our motor in the long run to leave it as is. We lso adjusted our brake tension. The brakes on this thing are killer!!! My daughter's boyfriend put an aftermarket replacement steering servo (about $100!) on his Savage X. That is awesome. I guess it is much more powerful and is able to turn the truck on a dime. Anyway, I'll footnote your tip and take a look at it.

kmatlock

Thanks for the advice Loswave. While purchasing the new truck, I did use my better judgement after watching and talking with a couple of guys at a local nitro racetrack, and purchased a heat temp! Read my reply to Vroddog1130 re the outstanding time that we had last weekend!

fourwheels0

My Feedback: (7)

yup these thing's take a little tinkering but once you get it set they are a blast. glad to hear you got your's going the way it should. just be careful these thing's can be VERY addictive.