More newbie questions...

[everlast73]

Ok, so I finally broke down and bought an RC truck, needless to say, I chose the Savage 21. It kicks ass. Thus far, I've gone through about 4 tanks of fuel, and I have a few questions:

1. I read the entire manual that came with the Savage; both the engine booklet and the manual with all the parts diagrams. I followed the break in, in the book, fairly close, the only step which was skipped was letting the truck run off the ground for a full tank; they started it and ran it for me before I left the LHS. I went through the first 2 tanks without really going over half throttle. I didn't do much tuning, I adjusted the Low Speed a bit and that was about all. The 3rd and 4th tank, I did do a little bit more throttle; probably almost full but never left first gear. After doing this, I read a few posts describing the "proper break in procedure"; they were a bit different than mine. I'm wondering if I went a little to quick, by getting it past half or 3/4 throttle by the 3rd and 4th tank; and also is doing this going to be detremental to my engine.

2. My hands are a mess. Yea, it got easier to start through out the day, I will admit that. I've been considering buying the RotoStart, but I am curious as to if I sould wait till after its broken in or does it not matter at all.

3. A few times when I started it, the engine would fire and run for like 5 seconds. When it stalled, it sounded like something was catching on the pull start. Is this normal? It did do that quite a bit in the beginning, but as the day wore on, and my hands, it got a bit easier.

I think thats it for now...Thanks.

 

[Error401]

First, careful break in of a new mill is a must. The purpose of the 1st tank idle thing is to get all the parts to mate and wear in a bit while the engine is running sloppy rich. The next few tanks are run in a very rich state, but lean enough to actually move the truck. After tank 5 or so, you start to lean the engine gradually, which in turn raises the temps so the engine gets used to operating at higher temperatures. After about tank 8 or 9 (sometimes 10) you should have the operating 1/2 tank temp up to about 230 to 250 degrees F, This is the "sport range". From 250 to 275 is the "performance" range. Above that and you risk cooking your engine. Getting ahead of the curve on this might also damage you engine, because it isn't getting broken in, it's being worn out prematurely. If you followed that book like you said, you're probably ok, but I wouldn't dog the engine too much for a few tanks.

Second, the rotostart is cool, but it's hard on the 1 way bearing (the bearing inside the pullstart). I have a roto, but I don't use it because of this. Some folks love it, some don't. Once you get your engine broke in and tweaked right, it should start on the first couple of tugs. IMO, putting an ignitor in my pocket and having a tweaked mill is nicer than carrying around a clunky roto, an ignitor and dealing with a pissy engine. They both start OK, but the first option is alot lighter on the feet.

Third, that noise you hear when the engine dies is the 1 way bearing. It makes this noise when the crank goes backwards on the last storke, and the 1 way is engaging and trying to suck the PS cord back in. It's normal, and that's why there's that bit of compressable tubing between the PS handle and the PS case (so it doesn't snap the cord).

Hope this helped,
Whitt.

And welcome to RCNT.

 

[everlast73]

Thanks, that all helped. I ran the 5th tank today, I didn't go too hard. I kept it mostly around half, a little more sometimes. I think its been running pretty rich, the right hand side of the chassis, where the exhaust is, is always coverd in an oily crud, which I am assuming to be the fuel it spits back out.

At one point today, about half way through the 6th tank, I hit the breaks and it died instantly...kept doing this for the next few starts. Afterwhich I figured that was time to call it a night. I made some adjustments tonight, but haven't had a chance to try them out....

 

[everlast73]

So yea, after a few good and bad runs, I finally got fed up and just reverted back to stock settings. I set the idle up so it didn't take off when it started and so there wqas enough play with the trim. I got it started and started doing the pinch test; i got it to run for about 4 seconds after I pinch the line. I ran it for about a half tank and took the temp and it was somewhere around 205-210; I think the highest it got was 220, but other than that never above 210. It still isn't shifting, but also I have yet to play with the high speed needle.

Prior to all this, it wouldn't start at all. So I set the needles back to default. After I did this, I had the air cleaner off, when I would hit the throttle or the throttle trim, the carb wouldnt't open. I know the needle was 3.5 turns out. So I set the needle closed then turned it to default, the carb started to move again. Directly after this, it started. My question is, why would that happen? Did I screw up the carb?

 

[Error401]

Ok, first off, your temps are good for breaking in. But you might want to lean the HSN a bit (maybe 1/4 to 1/2 turn, but go in 1/8th steps while checking the temps). Check the temps after a couple of WOT passes. Chances are that the engine is too rich to produce the RPMs needed to shift. Once you get the temps up to about 230 it should start shifting, if not, let us know because there may be something else you might need to check.

Second, ya kind of lost me on the throttle moving thing. Always remember to never touch the MRN (the one opposite to the throttle slider). When you say the throttle wasn't moving before you adjusted the LSN, did you mean the slider wasn't moving when you applied throttle?

As a general rule of thumb, if the engine won't start or run right, take the needles back to factory and work your way from there. I wouldn't touch the LSN until you have gotten it to run within temp (about 230 to 250). Then start adjusting the LSN for acceleration without bogging. The pinch test was to see if the case was loading up. But 4 seconds is pretty good to start off at. My Picco 26 it tuned for about 1 to 2 seconds, but that's for acceleration and it idles at 210 and WOT 270. When you start tuning the LSN, you'll have to retune the HSN to compensate. It's like a dog chasing it's tail for a while, but once you get the LSN set, it shouldn't change (unless you change altitude alot in different areas). After that, tune the HSN only for the proper temps.

I don't think you messed up your carb, unless you torqued the needle fully closed. If you only lightly bottomed out and then came out to the factory turns, it should be fine. Just don't run without a filte. It takes nearly nothing to mess up a cylinder.

 

[everlast73]

The slider inside the carb; it wouldn't moce no matter what I touched. I other words, it wasn't opening to allow more gas to flow through...I guess that's minor at this point, it runs, pretty well I might add. I will try to lean out the high speed next and see what happens...Thanks.

 

[everlast73]

So today I went and started leaning the high speed, I went through one tank, I think the temps were somewhere around 240-250. It was pretty damn zippy, I was seeing smoke from the exhaust and all the other signs. The next tank, which I think was my 8th or 9th, I kept playing with the high speed; temps where in the same range, about 240-255. About half way through, it started to shift, without any adjustment of the tranny. After the tank I took the temps and I think I was around 255; I think the highest it got was like 265 to 270, but I richend it up.

Now I think it may be on to tweaking the 2nd gear thing. The shift isn't all the time; sometimes I will tach it up, and it won't shift, if I left off and gas it, it will shift. When it does shift it seems to bog. Don't get me wrong its still fast; when I whack turns in 2nd it wants to flip.

One thing that confuses me is, if I am running hot, how do I tell which needle to richen/lean?

Thanks for all your help thus far...

 

[Error401]

If you're running hot, always adjust the HSN. Messing with the LSN will only make hole shots cranky (bog or die). Once you get the LSN set, it won't need adjusting, unless you change altitudes (like going to the mountains and such).

It's good to hear that it's shifting now. It will start to shift more as the shifter wears in. One thing to check is the slipper adjustment nut. That's the nut on the shaft that the spur gear is on, with the spring near the throttle linkage. The proper adjustment is tighten it all the way, then back it off about 1/8th of a turn, 1/4 max. I run mine all the way in with my picco 26. If it's too loose, the engine will spool up, but the tranny will not shift right. Essentially, the second gear shaft in the tranny (the one with the shifter) must be turning a certain RPM for it to shift. If the engine isn't putting out enough power to get it up to that speed, or the slipper is slipping too much and not letting the truck get up to speed, it won't shift. The last resort is to adjust the shift adjustment screw. Out means earlier shift, in is later shift. You would want it to shift earlier (lower shift threshold speed). The ideal point is to get it so that it shifts smoothly at a high midrange RPM. Make sure the shift is well within the power band of the engine (not too early), but not near redline (too late).

Sounds like you're getting the hang of it, and it'll only get easier as you get to know your truck.

Whitt...

 

[everlast73]

It seems to be shifting all the time now, some times it shifts late, but if I lean it out, it seems to go a little earlier. I started to run it today with the body on. But for some reason, it would just get too hot; got up to like 310 at one point. I kept richening the high speed but I couldn't find a happy medium. The more I richened it, the shittier it ran. So I took the body off again, and it went back to normal; around 250-265. I've also noticed, when I get below a half tank, I start getting a lot of air in the fuel lines. I assume its because of the way the fuel line is set up with the nozzle coming out the fuel tank being in the front. When I give it any gas, all the fuel runs to the back. I going to see if I can rig something up. Other than that, its fast and fun...

 

[Error401]

It helps if you cut some holes in the front windshield and the rear windshield on the right side to get some better airflow to the head when you have the body on. Also, try different plugs and fuel. I like Blue Thunder, and it seems to run cooler burning that instead of Byrons.

Glad to hear that it's running (and shifting) better now.

 

[everlast73]

After a few days, I got to take the truck out again. I did a few things in the meantime; I put a hole in the back of the fuel tank with a brass nipple and plugged the stock hole with a screw and some loctite. No leaks as of yet. I put a fuel filter in too.

One thing that has been happening, at about half a tank, the engine will just stop. When I go to start it, it usually starts on the first pull. It does this almost every time. I don't think there was air in the line, it was kind of dark I couldn't see too well.

Also, the throttle seems to be sticking. How often should one replace the receiver batteries? Today at some points, I would pull the trigger and the throttle wouldn't budge. After a few seconds it would go, this would happen sporadically. I changed the batteries on the controller while I was driving and it still happend.

 

[Flash-R.C]

My experience with the .21 bb engine is that it took about a gallon for the temps to drop below 300. It always ran hot. I thought i ruined the engine at the time. Then after a gallon temps went way down to 200-220. I thought the engine might be dead but it hasnt died yet. I got 4 1/2 gallons through her and she still has loads of compression. It actually has more compression right now than it did during that first gallon bsides the 7-8 break in tanks. I think your engine should be fine.

P.S. Many people who have been running the S25 have noticed temps around the 300 point. Someone I know has put a 1 1/2 gallons through and it is running better and at lower temps.

Steve