rattyocaster Posted October 7, 2009 Share Posted October 7, 2009 Hi there, I'm fairly new to running Nitro RC cars (well the last RC car was a Quote Link to comment Share on other sites More sharing options...
matt_green84 Posted October 8, 2009 Share Posted October 8, 2009 Engine dying at full throttle is definately down to High Speed Needle setting. From where you have it set, turn it an eighth of a turn clockwise. Do a high speed pass. Better or worse? If its better, your going the right way. If its worse, go an eighth the other way. Better? Go another eigth the same way. Better or worse? If its better, keep going, worse, go a 16th of a turn back etc etc. Its hard to get right, and it is a bit of a black art initially, but take your time, make small changes and don't change more than one thing at a time. Awkward starting is down to it being new, and not tuned quite right. If it starts, you'll get there with a bit of tuning. Smoky grass isn't really a problem, my mate's revo does exactly the same, and smoke means that the engine isn't running too lean, which can cause damage. Finally, revs rising may be clutch slip, but its more likely that as the engine warms up, it is running leaner, which is causing higher revs. Which is why you should tune your car for when its warm. Hope this helps, if so click the + down there >>> 1 Quote Link to comment Share on other sites More sharing options...
Beddo Posted October 9, 2009 Share Posted October 9, 2009 I was always under the impression that if the motor cuts out at high revs, the engine is too lean? By turning clockwise, your gonna make it even more lean...... What sort of temps are you seeing at the glowplug after a couple of WOT runs? Theres a really good tuning flowchart here which you might find helpfull. 1 Quote Link to comment Share on other sites More sharing options...
rattyocaster Posted October 9, 2009 Author Share Posted October 9, 2009 As it happens, I have worked out why the engine was going faster and the car not. Weirdly under braking so it would appear, the rear driveshaft has been damaged in some way, as a result only the front wheels are turning under the power of the engine which is why on the damp grass it was just revving and not going any faster, because of course under acceleration all the weight shifts off those wheels, reducing their available grip, compounded by the damp grass. I tried it after the night I was having these issues (well it was the same time I found out about the rear driveshaft) and it did change gear properly. So my 2 week old MTA 4 is no longer 4WD. The weird thing is, it appeared to happen under heavy braking, as if the brake was on the rear driveshaft because after losing the rear drive, the brakes have been poor as well. Just to note I haven't been revving it with it picked up off the ground or anything stupid like that (other than a gentle flick of the throttle to confirm my original thoughts on the driveshaft situation - after damage had been caused) Beddo, I don't have anything to check temperatures with other than "OW that's hot" as I proved on my car's exhaust when reaching for the pull start once, but I learned my lesson, use an electric drill instead and it makes it start MUCH more reliably! I take it that I need an IR thermometer then! I will say though that the tuning guide will come in most helpful once my car is running 4WD again. One thing which might sound stupid but the temps in that guide are in degrees C not F right? Better to be safe than sorry and all that. Quote Link to comment Share on other sites More sharing options...
mgtuser Posted October 9, 2009 Share Posted October 9, 2009 loosing rear drive will probably be a cause of the grub screw coming out of the driveshaft, where it secures in the coupling. ( driveshaft from the gearbox to the diff, there should be a large round coupling the shaft secures into, these are normally blue, but may be red in colour ) mine did this, so make sure you threadlock the grub screw in, then put something around the drivecup so it stops the little pin coming out. some use heatshrink for this, i used some tape and a cable tie for good measure to modify mine....never lost another grub screw or pin again!! ( do this to the front one too, and make sure ALL those grubscrews are threadlocked in well...) 1 Quote Link to comment Share on other sites More sharing options...
PKNEC Posted October 13, 2009 Share Posted October 13, 2009 (edited) Hi mate I have an MTA4 and had a few issues with getting it to run correctly. The problem I discovered is that the car had more than a few screws loose the crankcase cover screws being just some of them. Once tightened the engine ran like a dream at factory settings. So have a good look at the truck and nip up any bolts screws that are loose. Considering it was an RTR I was a little dissapointed that build quality was as I found on my car but a couple of hours spent checking the car out where well spent. PS .don't forget to fit a failsafe Edited October 13, 2009 by PKNEC Quote Link to comment Share on other sites More sharing options...
The Trooper Posted October 13, 2009 Share Posted October 13, 2009 to be honest mate RTR truck or not, all screws should b checked before running Quote Link to comment Share on other sites More sharing options...
quattro Posted October 15, 2009 Share Posted October 15, 2009 I had the front wheels running at the end of my beach bash a couple of weeks ago turned out to be one of the rear wheels had come loose and the hex had worn the wheel away thus not giving the rear wheels drive under acceleration this may be your top end woes ie reving high but not going any faster have a look to see if the inside of the wheel has worn out. if you think its running to lean when it stops give the little fuel primer bulb a squeeze when you do if you hear a hissing noise its more than likley to lean as the hissing noise is the fuel boiling in the carb ie to hot what % fuel are you running ? Quote Link to comment Share on other sites More sharing options...
rattyocaster Posted October 15, 2009 Author Share Posted October 15, 2009 I'm using 16% fuel. When it cuts out at speed it doesn't seem to lose power as such it just stops, as if it's stalled and as soon as you let go of the throttle, the engine seems to start up and go down the revs as the car decelerates. I'll try playing with the primer bulb next time I take it out and it does it, but in my opinion, I think it's flooding at high speeds since it's running too rich and can't burn the fuel quick enough, especially since the engine stays off as long as the throttle is open, let go of it and then the engine starts whilst it's slowing down. As for the drive issue, the shop I bought it from said I should take it in for them to have a look at. I know it's lazy and it's my model but when I bought it they said "Any problems and just let us know" so...I have done. I know this has probably done my credibility a lot of harm (well I've had it 2 weeks and it's caused damage to itself on a fairly integral component, the idea of dismantling it is pretty daunting!) but has anyone else here (I know this is a stupid question but I'm interested) had anything back from Model Zone after repairs, if so, was everything ok? Quote Link to comment Share on other sites More sharing options...
MrPug Posted October 16, 2009 Share Posted October 16, 2009 I'm using 16% fuel. When it cuts out at speed it doesn't seem to lose power as such it just stops, as if it's stalled and as soon as you let go of the throttle, the engine seems to start up and go down the revs as the car decelerates. I'll try playing with the primer bulb next time I take it out and it does it, but in my opinion, I think it's flooding at high speeds since it's running too rich and can't burn the fuel quick enough, especially since the engine stays off as long as the throttle is open, let go of it and then the engine starts whilst it's slowing down. As for the drive issue, the shop I bought it from said I should take it in for them to have a look at. I know it's lazy and it's my model but when I bought it they said "Any problems and just let us know" so...I have done. I know this has probably done my credibility a lot of harm (well I've had it 2 weeks and it's caused damage to itself on a fairly integral component, the idea of dismantling it is pretty daunting!) but has anyone else here (I know this is a stupid question but I'm interested) had anything back from Model Zone after repairs, if so, was everything ok? When my engine wouldn't go full throttle (bog/cut out) it was the glow plug. Spend a fiver on a new one and it could save you weeks of pain 1 Quote Link to comment Share on other sites More sharing options...
rattyocaster Posted October 16, 2009 Author Share Posted October 16, 2009 When my engine wouldn't go full throttle (bog/cut out) it was the glow plug. Spend a fiver on a new one and it could save you weeks of pain Ahhh, you could be onto something there, it could also explain why it's a ***** to start using the pull start. When I get it back, I'll try changing the glow plug I have 2 spares which the people in the shop suggested were better...The ones I've been advised toget by the people at the shop were REDLINE R3's instead of the REDLINE R2 which was on the model when I bought it. If someone can tell me which is better I'd be most grateful Quote Link to comment Share on other sites More sharing options...
MrPug Posted October 16, 2009 Share Posted October 16, 2009 Ahhh, you could be onto something there, it could also explain why it's a ***** to start using the pull start. When I get it back, I'll try changing the glow plug I have 2 spares which the people in the shop suggested were better...The ones I've been advised toget by the people at the shop were REDLINE R3's instead of the REDLINE R2 which was on the model when I bought it. If someone can tell me which is better I'd be most grateful Dunno about the redline plugs, but my .28 seems to run better with a hot plug. It's weird as I thought colder plugs were better for larger size engines?! I'm currently using an OS A3 (hot) in mine (before that I was using a OS 8 medium). cheers Quote Link to comment Share on other sites More sharing options...
mgtuser Posted October 31, 2009 Share Posted October 31, 2009 Dunno about the redline plugs, but my .28 seems to run better with a hot plug. It's weird as I thought colder plugs were better for larger size engines?! I'm currently using an OS A3 (hot) in mine (before that I was using a OS 8 medium). cheers a hotter plug will make it idle a lot better, however your engine wont last as long if you keep using them. a .28 will create more heat than a .21, so you need a colder plug to compensate!!! McCoy Mc9 plugs are good for the Mgt/Mta4 Quote Link to comment Share on other sites More sharing options...
gazb1488 Posted October 31, 2009 Share Posted October 31, 2009 to be honest mate RTR truck or not, all screws should b checked before running im with the trooper, that is the nature of the hobby. ready to run in my opinion is ready built not nikko ready build never have to touch it again. after every run i check all the screws i havnt thread locked. Quote Link to comment Share on other sites More sharing options...
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