Problems tuning a savage xl

[Howhigh69]

I just purchased a savage xl. First rc truck. It sounds great on a bench and sometimes I can even get it up to full out throttle. I have ran 5 tanks of fuel through it. I did mange to run 1 tank on a cement parking lot with about 15-20 starts. The problem is as soon as I start it if I don't pull the throttle it will barely start. If I udjust the throttle trip up it will start but at a high rpm. When I go to put it on the ground it wants to take off right of way. I let it go about 30 feet and then I can use the brakes to stop it. if I apply the brake right of way it stalls. If I stay on the gas it will run for a while. It is fast but a few guys that had a 4.6 tell me it should be much faster. I can live without the speed? I just to be able to drive it for more then 3- 45 seconds.

Any ides. I am suspecting timeing or tuning on the engine. I have ried all the info. that is in the brochure. It doesn't seem to want to work for me.


Frustrated.....

 

[JessF]

sounds like 3 things are going on here.

1.You may have the high speed needle set too rich causing fuel to build up in the carb and once you pull the throttle all that fuel dumps causing the engine to bog down and stall.

2.The second thing you should check is your throttle trim. You can do this with the engine off. Pull the trigger for wide open throttle. See if you can pull the throttle open even more by hand, if so you need to adjust the throttle trim so that the servo pulls the throttle all the way, not 90%. If you adjust the trim too far you'll hear a persistant buzzing noise from the servo, this means you need to back the trim off until the buzzing stops.

3.The third item could be the idle screw. You need to pull the rubber air filter thing off so you can see down into the carb. There should be a 1mm gap(check your manual, could be 2mm, it's been a while since I've tuned a nitro). If you apply the brakes and the gap closes slightly this is causing the engine to stall when the brakes are applied. You need to adjust the brake linkage at this point, NOT THE TRIM, as you've already adjusted your trim for throttle response in step 1. Loosen the brake linkage so that it no longer holds the carb open, then loosen the linkage a bid more just to make sure. Do a test by applying the brakes with the radio, the carb should not muve when the brakes are applied. If you've done this correctly you can now adjust your idle screw to get the required gap, 1mm or 2mm what ever your manual says. It only needs to be by eye, no need to stick something down there to get exactly 1mm. Close is good enough. Once this is done you may need to tighten the brake linkage for response.

Do these steps in order and at the end of step 3 check your throttle trim to see if it still opens the carb all the way, not just 90%. Adjust your brakes by loosening the linkage. Until you get a radio with end point adjustments (EPA) you'll need to adjust your throttle by trim and brakes by linkage.


if you're still having trouble, I'm starting up my HPI RS4 for the first time sometime this week and I can go through these 3 steps and make a youtube video.
hope that helps.

 

[Howhigh69]

Wow,

#2 helped alot I am still working on #1 So far so good. Thanks a bunch
I will work on # 3 on a nicer day. It's good to know that there are people out there who can help.




QUOTE=JessF;786495]sounds like 3 things are going on here.

1.You may have the high speed needle set too rich causing fuel to build up in the carb and once you pull the throttle all that fuel dumps causing the engine to bog down and stall.

2.The second thing you should check is your throttle trim. You can do this with the engine off. Pull the trigger for wide open throttle. See if you can pull the throttle open even more by hand, if so you need to adjust the throttle trim so that the servo pulls the throttle all the way, not 90%. If you adjust the trim too far you'll hear a persistant buzzing noise from the servo, this means you need to back the trim off until the buzzing stops.

3.The third item could be the idle screw. You need to pull the rubber air filter thing off so you can see down into the carb. There should be a 1mm gap(check your manual, could be 2mm, it's been a while since I've tuned a nitro). If you apply the brakes and the gap closes slightly this is causing the engine to stall when the brakes are applied. You need to adjust the brake linkage at this point, NOT THE TRIM, as you've already adjusted your trim for throttle response in step 1. Loosen the brake linkage so that it no longer holds the carb open, then loosen the linkage a bid more just to make sure. Do a test by applying the brakes with the radio, the carb should not muve when the brakes are applied. If you've done this correctly you can now adjust your idle screw to get the required gap, 1mm or 2mm what ever your manual says. It only needs to be by eye, no need to stick something down there to get exactly 1mm. Close is good enough. Once this is done you may need to tighten the brake linkage for response.

Do these steps in order and at the end of step 3 check your throttle trim to see if it still opens the carb all the way, not just 90%. Adjust your brakes by loosening the linkage. Until you get a radio with end point adjustments (EPA) you'll need to adjust your throttle by trim and brakes by linkage.


if you're still having trouble, I'm starting up my HPI RS4 for the first time sometime this week and I can go through these 3 steps and make a youtube video.
hope that helps.[/QUOTE]

 

[JessF]

good to hear. step 1 may take quite a few turns before you notice anything. WHen I started my XL for the first time I think I had to lean it out at least 4 turns before I noticed anything. After that the tuning was all done within 1/2 a turn. As the engine breaks in, you'll need to richen the mixture.

Best thing to do maybe is lean it out to the point where the engine stalls, then back it off. Gives you and idea where the range is. Just don't run the engine up and down the street in a lean condition. If it's too lean it'll sound like a purring cat with torrets. If that happens, stop driving and turn the engine off imediately. Let it cool then richen the HSN 1/4 and start it back up.

one other thing I should have mentioned before. The k5.9 is notorious for leaking straight from the factory. If an engine is leaking you'll never get it tuned properly, nor will it keep a tune. Check around the engine for oil build up. Signs of a leak.

if you find a leak, seal if before doing anything really.