Mayhem RTR not running through full tank..

[Network]

When the fuel tank gets to 1/4 of a tank it will treat it as if it is empty and the only way to get fuel to the motor is to put more in it. Surely this isn't normal with 1/8th scales? Is there any way to fix this?

Travis

 

[jon2]

Is it dieing? Is temp going up? What are you seeing?

 

[Network]

It is dying like it is out of gas, however there is still 1/4 a tank left. It will not start over at all until you put more fuel in it (Like its empty) then it acts normal again.

Travis

 

[jon2]

hmm sounds like it may be too lean. try richening the HSN and try running a full tank. Do you have a temp gauge? Find out what the temp is after you run a few laps with it.

 

[Network]

Ok I will give that a shot thank you.

Travis

 

[Candyman]

It sounds like you are running into that self-leaning problem or else there's a fuel pickup problem. Most likely it's the self-leaning. I'd do as jon says. Richen it a tad and see if you can get through a tank.

 

[Rolex]

Just to check one more thing here, are you trying to restart it while it's still hot? The self leaning will also cause the engine to run hotter. Just to isolate the problem, if it happens again, let the engine cool down completely before restarting it, and see if it will run without refueling.
More than likely, it's too lean, and overheating.

 

[mikeburgin]

if it always does it at the same point in the tank i would be checking the internal pickup in the tank, i have had them with faulty pickups that have had a crack or hole in the pipe and they do exactly that, they run out of fuel
get the tank to were it runs out then blow down the presure hose, if its bubbly or no fuel being pushed down the line then this is your problem, if its getting constant fuel then try one of the above

 

[Sgt Blamo]

Stick with it and be patient,you'll get it figured out and be having a blast in no time. Just listen to Rolex and you'll be squared away (not knocking anyone else!)

 

[Rolex]

Thanks for the vote of confidence, Sgt Blamo, but this is a buggy I'm not familiar with, and it might have issues common to that model.
Network, a normal running temp is what we all need to know here. If it's running a little on the high side, the leaning out towards the end of the tank will cause it to over heat and not restart till it cools down. There's the possibility that it cools enough while you try to start it and then add more fuel.
If you don't have a temp gauge, you need to let it cool down completely, then try to restart it BEFORE you add more fuel. This will help isolate your problem.

 

[Network]

Thank you all for your help, I did not get to work on my car last night like I had planned. I do have a temp guage. Is there a tutorial or article somewhere on the internet that explains the HSN, LSN, and Idle Needle? I am completely lost on these concepts..

Travis

 

[Candyman]

Here's a thread that has a few links to point you in the right direction. Just remember, tuning takes a little time so just do it step by step, one needle at a time...

https://www.rcnitrotalk.com/forum/showthread.php?t=26800&highlight=engine+tuning

 

[AC48]

There has got to be something like that on the net, but I'll give the basic idea on what they do.

HSN - This is the big needle on your carb. It will regualte how much fuel the engine gets in the higher RPM range. You turn it to the right (tighten) and there will be less fuel in the engine. This will give it more performance, however it will get less lubrication and will wear out faster. You turn it to the left (loosen) it will be given more fuel. This will cause lower temps, and more lubrication giving it a longer life. What most people want is a slightly rich mixture of fuel and air to get good performance but still have a long engine life. Tune the HSN until you get good, consistant performance and you always see a trail of smoke at WOT. After you think the engine is tuned THEN check your temp to make sure you are not over 280 degrees or so. Don't tune the engine to run at a certain temp, all engines run better at different temps, use the temp gun just to double check your engine is within a good temp range.

LSN - This needle is located on the slide valve or on the rotary part of the carb. It has the same concept as the HSN, just for lower RPM range and idle.

Idle adjustment - This is just a stop screw stopping the carb from closing completely. This is so that when you hit the brakes your engine will not stall. Turn it in to raise your idle and loosen it to lower your idle.

If you already knew this then oh well, somebody might need it

 

[Network]

Wow that thread is awesome, it has a ton of information.

AC48 -- Thank you, I have a complete understanding now of those needles hehehe.

Travis

 

[Candyman]

Yup. Good place to start. I'm hanging on a few of these threads because I just got my Mayhem RTR in the mail yesterday. So I'm reading up on what everyone else is experiencing.

 

[AC48]

AC48 -- Thank you, I have a complete understanding now of those needles hehehe.

Travis

No problem. Good luck with yout Mayhem

 

[Network]

Yup. Good place to start. I'm hanging on a few of these threads because I just got my Mayhem RTR in the mail yesterday. So I'm reading up on what everyone else is experiencing.

In a previous thread I had noted that the first thing I was going to replace on the Mayhem RTR was the front/rear shock towers..Well mine came with the Pro Shock towers. Huge difference between the Pro ones and the RTR ones. I don't know if they are doing this for all RTR kits or not, but there is a guy at my local track with a RTR that has the skinnier shock towers.

Travis

 

[Sgt Blamo]

Did you ever get it running right?

 

[Network]

Yup. I ran it through probably 10 tanks yesterday at the local track. I am going to be racing tonight (hopefully) if I can get off work early enough.

Travis

I would just like to note that this car is a blast to drive!

 

[Candyman]

So what do you think was the problem? Was it solved just by a simple readjustment of the needles? Or was it a fuel flow problem? Just want to make sure I don't run into it. And did you find that your LSN is a pain to turn? I checked the initial settings on the carb the other night just getting ready to break it in. And turning that low speed needle was really tough. Was yours like that?