short run times

[miketrav69]

Hey guys i have a exceed forza nitro buggy. Been using off and on for about a year. I have all the needles set right with perfect performance and power. Problem is I only get like 3 minutes per tank. I do not see any leaks. I thought it was to rich cause gas was comming out the pipe. I readusted and that does not happen anymore. Yet i still get like 3 min per tank... any ideas guys

Thanks in advance...

 

[MotoGod]

You sure your High Speed Needle isn't set VERY rich? I had this problem with my buggy at first. I was just pouring raw fuel out at full throttle and not burning it. Also how big is your tank and your motor? Not familiar with the Forza, but Even my RC10GT had a 75cc tank with a .12 motor and ran for damn near 15 min on a single tank. My Revo runs a good 12-15 and my buggy at least 12.

3 min sounds like a problem to me. Either you have a hole in your tank, or your too rich. That's all I can think of here...

 

[miketrav69]

thanks for the reply... If i set the needle any less rich the motor will stall out when throttle is given. The fuel tank is solid. I am at a loss here. It has been running like this since day one. The car runs amazing, but this weird fuel problems costing to much money. Any other advice would be great

link to the buggy http://www.raidentech.com/bgrxt21scnif.html

thanks

 

[MotoGod]

It will stall? That seems odd, unless your WAY lean already. You can pretty much lean it out to the point it blows itself up pretty quickly...which is VERY VERY lean. Are you seeing a nice trail of smoke come out the exhaust when at full throttle? What temps are you running?

 

[miketrav69]

yea nice trail of smoke. I was pretty lean. Actully it would not stall. It would just kind of lose power at high throttle. Like if it was trying to get out of grass or something it would lose power. I fixed that by turnining the needle a bit and making it more rich. I no very little about nitro cars. My main hobby is electric helis. I wonder if my carb leaks or something? Could the engine leak? Where is a good place to start to figure it out.

Thanks

 

[MotoGod]

Well you could test for air leaks....but that won't explain why you have 3 min run time....unless you have fuel puddling under your motor or something. How big is the tank? Looks like the motor is a .18 so you should see decent run times from that motor...even if it's a 75 or 100cc tank!

Is the car covered in Nitro after a run or anything? Is your exhaust gasket tight?

 

[RC Addict]

Definitely test for air leaks. The reason you are only getting a limited run time is because you are ultra rich. The reason you are ultra rich is because your tune is set to compensate for your lean condition. The fact that you said that leaning your rig out causes it to stall and or loose power proves it.

 

[MotoGod]

I knew someone would chime in! Air Leak definitely would make it run lean....well at least I was on the right track. hehehe

 

[traxxas t-maxx]

Well if its getting about 3 minutes into run time the engine is just getting warm it could be a bad engine.

 

[miketrav69]

Hey guys thanks for the help. I noticed some fuel comming out where the tube goes into the carb, but only a bit. I also tightened the thing that hooks into the carb where the tube conects too. I get about 5 min run times now. So How do i check for air leaks? I asm at the point with the needle, if i turn it at all to make it any less rich the engine willperform poorly. There must be a leak or air leak. Where are some common other leak places to check. Can the engine leak?

thanks

 

[crk]

Go to your LHS and buy some new fuel line. Replace all of your old line with the new line. See if your run time improves. Also make sure that the filler cap o-ring is sealing on the fuel tank.

 

[RC Addict]

An air leak check is easy to do. First get a bowl of water and add some dish soap. Then get a brush. Remove your air cleaner. Lightly brush some soapy water solution around your carb base, needles, exhaust outlet, fuel tank, etc. Remove the pressure line from the exhaust. Blow into the pressure line while plugging the carb opening and the exhaust. If you see little bubbles you have an air leak.

This is the easiest way to test the whole system without having to take everything apart.

I knew someone would chime in! Air Leak definitely would make it run lean....well at least I was on the right track. hehehe

It is the only thing I can come up with that fits his description...

 

[alpinehyperlite]

If you have a fuel filter, also check there. They are notorious for leaking.

and that does look like a TINY fuel tank.....

 

[RC Addict]

75cc still outta give him more that five minutes, no?

 

[alpinehyperlite]

its been a while since I've run nitro..... also depends on throttle. How do you drive. Wide open all the time, or just easing into it...... But it should. 75cc with a .18 with a bad tune will give very short runtimes.



Are there bubbles in your fuel line?