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F4.6 Tuning problem

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Danimal

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I've only got about 2 gallons through my Savage-X so far and I'm working on getting my tune up nailed down. But I'm having a problem with the engine shutting off after short full throttle bursts. My temps are good around 232 to 258 usually. If I do long full throttle runs its not a problem only quick 3, 4 second blips will kill the engine every time. Any ideas what could be causing this?
 
It sounds like a LSN adjustment if you're doing the blips from a standtill. Tough call without seeing or hearing it, but you are either starving for low end fuel, or flooding it. Lean it just a hair on the LSN and see if it changes or gets worse. If it improves, lean it a tad more. If it doesn't help, then do the same to richen it. Your HSN seems ok with long runs.
Watch your temps. You might need to richen the HSN needle afterwards.
 
I did like you suggested and leaned the LSN about a 16th of a turn. As soon as I did the idle started to climb. It wasn't trying to run away on the ground but on the stand it was spinning the tires at a pretty good clip. Something it has never dun before. I can usually set the idle on the stand so that the tires don't move but the clutch is right at the point that it is giving little tugs. Since it wasn't running off on me I gave it a try and the small adjustment did help with the problem. But now I can't get the idle back down and my temps are hitting 278 after a couple high speed runs. I've got it running so rich now on the HSN that its belching clouds of smoke as I get on the throttle and spewing oil out the pipe all the time.But I can't get the temps back down to under 256 after a run. The temp comes up pretty quickly no mater how I drive. I can watch them come down at about 1 degree every 1&1/2 seconds but once it hits 260 that's it it wont drop below 256 unless I kill the engine. But if I start with the engine cool and let it sit there it will idle at 232 as long as I let it run. I don't get it. What have I dun wrong?
 
Air leak?

Danimal said:
I did like you suggested and leaned the LSN about a 16th of a turn. As soon as I did the idle started to climb. It wasn't trying to run away on the ground but on the stand it was spinning the tires at a pretty good clip. Something it has never dun before. I can usually set the idle on the stand so that the tires don't move but the clutch is right at the point that it is giving little tugs. Since it wasn't running off on me I gave it a try and the small adjustment did help with the problem. But now I can't get the idle back down and my temps are hitting 278 after a couple high speed runs. I've got it running so rich now on the HSN that its belching clouds of smoke as I get on the throttle and spewing oil out the pipe all the time.But I can't get the temps back down to under 256 after a run. The temp comes up pretty quickly no mater how I drive. I can watch them come down at about 1 degree every 1&1/2 seconds but once it hits 260 that's it it wont drop below 256 unless I kill the engine. But if I start with the engine cool and let it sit there it will idle at 232 as long as I let it run. I don't get it. What have I dun wrong?
Click to expand...

You could have an air leak....maybe?
 
I mentioned in the earlier thread to keep an eye on the temps, since leaning it out would raise it. Leaning will also raise the idle, and you need to bring it down with the idle adjustment screw. Bring your LSN back up since you're running too hot, and richen it a little this time and see how it behaves. Again, this time you might need to raise the idle setting. Just remember, the LSN is for idle, punch off the line and low end pickup. On WOT it's in the HSN. There's a magic balance you need to hit between the LSN, HSN and the idle setting. Just a tiny bit at a time, and don't adjust the HSN till the LSN is good and the temps look good while just idleing.
If you have a problem with surging, you might have an air leak as BOUTCH suggested.
 
Hay guys thanks for the help. I'm starting to think you might be right about the problem being an air leek. I had the chance to run a couple tanks through it today.When I first started it it was so rich I couldn't get the temps over 207 and it was belching smoke, bogging down and had no top end. I leaned out the HSN a little and it really came to life. Idle was perfect, performance was better than I had ever seen it and the temps never got over 258. I thought I had the problem licked. After work I decided to give the truck a good cleaning. I hit it with some nitro cleaner and stuck a new air filter on it.When I fired it up the second time today it started acting up again. The same thing it was doing before.
I'm going to brake it down this weekend and seal the engine. I guess I should have dun that before I even started it for the first time.

I guess the newbie light is really shining on me this time.
:alarm: :n00bie::alarm:
 
Danimal said:
Hay guys thanks for the help. I'm starting to think you might be right about the problem being an air leek. I had the chance to run a couple tanks through it today.When I first started it it was so rich I couldn't get the temps over 207 and it was belching smoke, bogging down and had no top end. I leaned out the HSN a little and it really came to life. Idle was perfect, performance was better than I had ever seen it and the temps never got over 258. I thought I had the problem licked. After work I decided to give the truck a good cleaning. I hit it with some nitro cleaner and stuck a new air filter on it.When I fired it up the second time today it started acting up again. The same thing it was doing before.
I'm going to brake it down this weekend and seal the engine. I guess I should have dun that before I even started it for the first time.

I guess the newbie light is really shining on me this time.
:alarm: :n00bie::alarm:
Click to expand...

:)Thats why were all here for...to help each other out!!! Good luck and keep us updated on this little prob.
 
I had a stock .25 that did that in my Savage and it ended up being a cut packing on the carb.....so it was sucking air real bad. The bad thing about it was it only did it when the engine was hot.....case expands, carb doesn't and there you have an air leak.... that made me buy another engine....so now the .25 sits on a shelf all by its self. Let us know what happens.
 
Hey Guys
I know I'm a bit slow giving you an update. But between my heli's my truck and work I am having a hard time finding the time to do it all. I may have to quit my job its cutting in to my hobby time to much.
Anyway ........ I finally got around to sealing my engine and making a few test runs. It helped some but I was still having trouble with the temps climbing over 265. Run times didn't seem to have anything to do with it. Sometimes it would start to heat up within the first 1/4 of a tank and then be fine for the rest of the tank after I let it cool down. Then other times I could run almost a full tank before it would start to get to hot. I finally found the problem after a pretty nasty high speed rollover that I thought had to of broke something. I stuck the truck on the stand to look for the broken parts that I was sure I was going to find. WOW this Savage is amazingly tough. A few new scratches and dents a small rip in the rear window opening and that was it. During my post crash inspection I found a vary small wet spot on my fuel filter. When I took the filter apart I found that the rubber seal had a nick in it that must have been causing an air leek. After replacing the rubber seal my over heating problem disappeared. Now the engine runs at a consistent 232 too 252 without the body and around 247 to 264 with the body on depending on how hard I'm pushing it. Are these numbers acceptable? Or do you think I should richen it up a little to bring the temps down some with the body on?
 
Glad to hear you found the problem. It doesn't take much to make these little screamers misbehave.
You're okay with your temps. The LSN has a lot to do with the overall running temp of the engine.
As the weather cools, don't keep leaning it to keep the temps up, just adjust it for performance and make sure you're seeing smoke.
 

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