mobr86

OK guys I just bought a brand new savage xl rtr. Ive been trying to get the first tank of fuel through it. I put the truck on a box and everytime i start it i have to put my finger over the exhaust to prime it. It dont matter if its hot or cold but it will not start without being primed. As it idles the engine is very jumpy. It idles fine for a couple seconds then starts jumping. Ive also noticed that there is always some air bubbles in the fuel line. Ive only got it to stay running for about 30 seconds at the most then it dies. What do you guys think is the problem

BudBud

Carburetor issue maybe, I would guess a pinhole in an air line or fuel tank. Make sure the fuel lid is seating and sealing. I have had some tanks you had to shut the lid with your thumb to get to seal. What happens when you have an air leak is that pressure from the exhaust line flows through the fuel system and out the leak. You may not be leaking fuel, but you are blowing a lot of excess air into the fuel. The bubbles go into the carburetor charge line and the results are what you are describing. Look for splits in the line at the connections between the tank and the carburetor. Glen

Shenanigans

My Feedback: (12)

agree with above...take fuel line off, plug one end with thumb and blow into it...should tell you if it has a hole.

nitrotec

increase your idle 1/4 clockwise turn and turn your lsn 1/4 turn counterclockwise. the jumping should stop. that tells me you are running lean on low speed and increasing the idle a little should help the stalling issue. your settings could be tempered with from the manufacturer (you can always reset them to initial setup). make sure you elevate the truck when breaking it in, such that the tires run freely and you dont ruin your clutch. g/l keep us posted

mobr86

Well I changed the fuel line with new fuel line and it idles for a few seconds then leans out and revs really high and i have to shut it down. I called HPI and they seem to think its a fuel tank issue. So they sending a new fuel tank. I sealed the motor to make sure it didnt have any air leaks. If its not the fuel tank then i dunno whatelse it would be.

nitrotec

did you try to increase your lsn? what do you mean by sealing the motor? did you take the back plate off? and did you take the carb off and sealed everything? did you use permatex sealant? i wish you didn't do this!! i think it is your low speed needle. can you post a video?i dont think is your gas tank. i had a cen truck that acted the same way, and eventually i swaped the carb!!keep us posted

BudBud

I have fought lots of carburetor gremlins in this engine. The orings Kingstar uses for both the low needle and the mid screw are too small and frequently they come torn from the factory. If you ever try to replace a set, you will quickly figure that out. Look for torn or flat spots on the low and high needle orings. Also, some of these carburetors had sleeve to carb body leaking issues. They bored the old Axial 32 carburetor out to a larger intake bore. Some guys actually had them split.

You posted that you are drawing air bubbles through the fuel line. That normally indicates an air leak before the carburetor. Did you try forcing the lid shut with your thumb? Checking the tank for leaks is pretty easy, put hoses on both fuel nipples, blow in the cap line and seal the carb line with a screw or small rod. Use some water and dish soap mixture, coat the tank and give it some air. These things operate on minimal pressures, much less than it takes to inflate a balloon, so be gentle. Glen

BudBud

Just adding that the original Hpi fuel line used on the XL is absolute junk. It is obviously from the cheapest source.

mobr86

Ok guys I checked for leaks in the fuel tank with soapy water and found nothing. I sealed the back plate and put a new o-ring on the carb and reinstalled it. Ill go ahead and check all the adjustment screw o-rings and see if any are broken. Ill also try my mgt fuel tank in the morning just to see if that helps. Also too i observed the air bubbles in the fuel line would float away from the carb. If that matters any. I asked HPI if it could be a defective carb but they wanted me to pay my LHS to look at it. If thats the case then i might as well fix it myself. When i first pulled the truck out the box i noticed the rear wheel would wobble when i spun it. Come to find out where the wheel nut screws on was bent. At this point HPI has yet to impress me. Hopefully that changes. BUDBUD, NITROTEC, and SHENANIGANS I appreciate you guys help so far. Thank you. Oh and if i comes to it can someone help me post a video. Thanks

Spdfrk

Depending on where you got it from, you might wnt to consider exchanging it for another one. Sounds like you may have just gotten a lemon or it was from a previous exchange.... The bubbles in the fuel line will cause the motor to run lean and increse the rpm. As mentioned, open up the low speed needle about a half turn and check the results. The bent wheel hub is definately a red flag.

BudBud

I was thinking about this while at work today and I have something I want you to try. Pull the fuel line off at the exhaust pipe. If you are one of those guys that fear nitro poisoning, use a new section of fuel line. Apply minimal pressure to the line and start the truck. You can vary how hard you blow into the line and make the truck run richer or leaner, kind of fun to play with..... What I am after though, is to make sure you do not have a faulty pipe. I have seen polished pipes by Hpi and Hot Bodies both that had very little or no fuel pressure. That would explain all of your problems. Also make sure the fuel lines are routed properly. From the pipe to the fuel lid, then from the tank to the carburetor. I have better luck with short fuel lines on the Savage. These Hpi polished pipes are of horrible quality, I gave several away a few years ago with that warning here on the forums. Glen

mobr86

Ok BUDBUD i gave that a try. It helped somewhat. But as i blew a little harder I noticed some fuel leaking from the High speed needle. Well i pulled the needle out and the o-ring was kinda like smashed and stretched. I seem to have trouble  finding this o-ring with out having to buy the whole high speed needle. I must of missed that o-ring last night.

BudBud

There's your problem, normally that ring is pretty good new, but if they tore it trying to install the needle, they will draw air into the engine. That will also make it next to impossible to tune.

The Axial 32 should have the same sized o-rings. http://www3.towerhobbies.com/cgi-bin...?&I=LXPDX4&P=Z

I like to assemble those with Associated Green Slime or dish washing liquid soap. The problem is trying to get the oring and needle in the tube without damaging the oring. After run oil will also work. There are some guys that say green slime is hard on orings. I never noticed that being a problem. Glen

mobr86

Ok BUDBUD. Ill go ahead and order that and take it from there. Hopefully after i change that o-ring it will start running right. I appreciate all the knowledge guys. Ill keep you guys posted. It will be a couple weeks as im offshore.

mobr86

Well guys I got home yesterday and put my new fuel tank on and I put the new high speed needle o-ring and for the heck of it i changed the o-rings on the other needles also. Well that didnt work. I can get it to idle half decent but it'll still start to gradually rev up on its own and jumps. If i kinda blip the throttle the engine will rev up wide open and stay running wide open and i have to pinch the fuel line to shut it down. I called HPI and they decided to send me another carb. Im starting to run out of solutions. I've never had a nitro engine do this. The temp will slowly climb to about 280 to 290 degrees

Yamaha911

I am currently having the same issue with my brand new savage xl. Iwas able to run the 3 tanks of fuel at idle Ijust kept richening the low speed needle an eight at a time until it would quick jumping around. The big problem Iwas having was that the temp was climbing in excess of 316 degrees. So I put a fan on it while it ran and that brought it down to 210 degrees. But now when I'm trying to run it on the ground with half throttle it will just run a for about 2 to 3 minutes and then die. It dies instantly when I hit the brake. So try messing with the low speed needle a little bit. Just keep track of how much you turn it. Now I get to figure out the next problem that Iam having with it. When I figure that out I'll try and let you know.

GRADEE

brings back memories of when i first got my savage XL.

ah the stress. nearly sold it haha.

glad i didnt though
hang in there guys.

BudBud is the man.

wolfie1

yea im the same as gradee, now out of all my models its my absoulute favourite, maybe you should take your engine out and seal it up ie the backplate , carb (where it goes into the crankcase), and the nipple where the fuel goes in on the high speed needle. i did this on 1 of my k5.9 and it sorted the problem out