do i own a lemon or am i just pathetic?

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hvymetalalchmst

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this is my first post. there are lots of problems (some which may seem obvious, but to me seem far from it) and I'm on the verge of absolutely obliterating my rc truggy

first of all; i own a sinyih truggy, about 5 years old, 1/8 4WD w/ 3 diffs, 3.5cc force engine, and cost me about AU$800 then. i only run on 10% nitro (its my personal preference). i got my LHS to build it for me, which i think is the stupidest thing I've done yet.

i think i need to detail everything because I'm not going anywhere soon

Ever since i got it home, nothing has ever been right. in the first six months, i did very rare weekend runs. storage for the next 12-24 months, tried it a few times, gave up, and back to storage. every 12-or so months i tried to get it started.
please note that i store it in a cool, dry garage free from anything bad, although i dont use afterrun oil. i dont store fuel in the fuel tank.

during the first year, i could barely get the damn thing started; it often flooded, and could not tune it. i think it was partly (not completely) my fault.
when the thing ran, with the occasional flood and unstartable fits, the truggy would randomly (and i mean randomly) run dead max speed, and veer left; it smashed into trees and fences a few time, pretty badly. thats when storage started. turns out my transmitters potentiometer (variable resistor connected to the throttle control) was set to much on one side, and hence would 'half-short'. I've since fixed that.

my glowplug has already had one untimely death (after only about 6L [2 gallons] of fuel). i did not have a label or reference number, but my LHS gave me a OS A5 plug (medium cool). i have always had trouble tuning the truggy, with both plugs, i think its due to inexperience. i can easily tune anything, that is, anything but this!

just lately I've tried to get it started, again. the problem is that it runs. but i think that the LSN has problems, when the pinch test works, it struggles up inclines from stationary, spraying lots of smoke. it feels weak and sounds as if its too rich, though leaning does no good for the engine. when i accelerate; ie from stationary-to-half throttle instantly, the thing kills itself. when i slowly accelerate, it seems to struggle, kind of pulsing, though does not pick itself back up. whenever i lean the engine, it easily kills in acceleration. it looks and sounds good off ground; i like a little richer mixture for open areas (i dont tune off ground, its just an observation). richening it seems to make problems worse. leaning makes it have epileptic fits. oh and when the piston is on the top of its stroke, i can hear some small air leak, but is a very, very faint sound (is it normal??!?!?!)

the engine now does not keep alive. i use a starter box instead of pulling now. and does not keep life as soon as the glowplug warmer is removed, about after 3 seconds. even idling higher cannot save it. to keep it alive, i rev it a bit whilst taking it out. the glowplug is an OS A5.

i have taken the engine apart before. it has no shims; just the block, glowplug-block thingy and heatsink. now it seems that fuel or something is leaking or is wetting the side of the engine block, and the silicon seal between the header and exhaust opening is leaking oil (i hope they are related). the fuel line seems to sometimes randomly pressurize, and requires screwing the HSN in then back out to relieve pressure to prime. just a few hours ago, there was a pressure build up again, and the engine flooded; i mean flooded with pretty much all 3.5cc of fuel.

I'm about to take apart the whole car inside out, clean and reassemble, hoping I'm gonna find some miraculous discovery which is going to fix everything. before i do, i hope you guys can help me out. and if there is anything you need to ask or are unclear about, ill try to answer as best i can. I'm in australia and it is currently 11pm on my watch; GMT+11 so i can't instanly answer all questions though ill get on every morning to check

thanking all in advance.
 
not that I am an expert...but man, there are a lot of obvious things wrong here...some that I have experienced too.

Firstly, get a hotter plug. Try an OS 8. Also, 2 gallons for one plug is not bad. I expect to replace my plug every gallon or so...sometimes it lasts longer, sometimes shorter. I know that when I was running my engine in, I went through 1 plug just for about 1 litre of fuel.

Secondly, get a higher nitro %. Try 20 or 25%. With 10% you will battle to hold an idle, and to tune properly. Once you have the higher % nitro (get a good quality fuel!), you will have to do a mini break in for your engine. Get all your needles back to there break-in positions (should be in the manual.). Break the engine in with about 3 tanks. Then, start tuning. 1/8th turn at a time, on the HSN only. Make sure you always have blue smoke...Once tuned at the top end, tune the LSN (if require, normally default position does the trick).

Also : ALWAYS use after run oil...you are asking for problems otherwise, especially if you are storing your truggy for long periods.
Regarding you electrics issues, can't really help ya out there.

Good luck!
 
Subby gave perfect advice here; I would also add that based on the struggling/coughing out of a lot of smoke, it sounds alot like an overly rich low needle. This in and of itself is not a bad thing; it's better to be rich than to be lean.

Now, as for your question of an air leak; it is conceivable that you do have a small airleak, judging by the noise you heard. Remove the engine, and make sure that all the screws on it are tightened, including the screws on the backplate (use a crossing pattern, as you would with a tire on your real car, and make sure the screws are TIGHT). Use a good quality wrench, not an L-shaped "key".

I will second the recommendation of a hotter plug. The OS A3 is simply too cold of a plug, especially for 10%. You want something hotter, definitely, as the fuel is simply dousing and cooling the plug off. Ask for something that is the equivalent of a McCoy MC59, which is perfect for 20-30%.
 
I go for a third on the hotter plug and higher nitro content. I even run 15% or higher in my plane engines. Try some 20% it will run better. Air leak....around your glow plug maybe? Try some dish soap and water the second you get it running so it is not too hot and drip around a few of the seal areas if you get bubbles...air leak it is.
 
Or you could let the engine cool down, and use some canned air (the kind that's used to blow out keyboards). Simply load the engine up with after-run oil, cap over the exhaust and air intakes, and use the canned air (with some fuel line and the spray tube supplied with the air) to pressurize the engine. It will reveal where you have an air leak.

I used that trick several times when I worked in a local hobby shop, as well as on my own engines.
 
I think you guys got your plugs the wrong way. The A3 is the hottest there is from OS. A8 is a medium plug.

edit: after rereading I can see the plug in question is a A5.....D'oh....I suggest a A3 with that nitro percentage.
 
another thing to add is you seem to have the "newbie" mindset of once you get this going you won't need to adjust anything anymore....don't kid yourself....engine tuning needs to be done VERY frequently......if the humidity or temperature of the ouside air change then your fuel to Oxygen ratio has changed in the engine and you need to retune.....
NEVER store your rig without using After run oil....you may have damaged the seal of the piston / sleeve with small pitting.....
Definately increase your nitro content in the fuel you are using and get a few new glow plugs to try and see what works best in you climate.....I wouldn't waste time trying to use a plug (or Fuel) that's been sitting for over a few months.....the head not having a shim could be a problem....I haven't seen any new mills NOT have a head shim and the chances of the head and crankcase being perfect is about a go-zillian to one......get some race sealant (hi temp RTV seal) and run a thin bead around the head/case and exhaust / header joints......and the carb throat......after letting something like that sit for soooooo long you really should do a complete teardown and inspect all the parts and make sure its lubed properly (I guarantee the diffs are dry by now)......save youself alot of trouble chasing later by going over and nut & bolt the whole thing now......welcome back the hobby and to this site......
 
G'day, mate. Wow, are you pathetic! Lol....just messing with you.:LoL:
Welcome to RCNT. That goes for you too, subby.
The info from subby was spot on. When you put the piston at the top of its' stroke, the slow leak you hear is compression coming back down past the piston. That is not a problem unless it's very sudden. All engines will do that. Go with the 20% and the new glow plug, then get back to us with the results. We'll get you up and running.
 
thanks for all you advice guys, i was gona try a hotter plug and higher nitro content fuel except that i didnt know if it was gona do much.

the air leak thing... ill just hope for the best in none, but ill take it apart today to test it.

just to note that any LSN adjustment attempts have failed me so far... i think the problem was the fuel and plug. and I'm very well aware of the frequent tuning required; there are no factory needle settings and i pretty much need to retune every single session just to get the thing started.

the heatsink is not perfectly flat, ie viewing from the side, it looks like a very flatly skewed hill-shape. it might contribute to the air problem. i think i might have slightly missed that :LoL:. i suppose that might contribute to an air problem. I'm gona shave it, unless you all disagree. and with headshims, i dont think my engine needs it.

but first will tear it apart and put it back together again (i dont think the LHS did a great job, there is not enough oil in the shockers to start with) and it will be about a week or so before i can get round to buying the parts. i like about 20 mins from any hobbyshop. guess its not that local then, eh?

and I'm gona get 15%, or would it still be too low?

once again, thankyou all who have contributed, really appreciate the help.
 
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if there is no headshim, then i would suggest to get one or two, use one now and keep one as a spare, a good plug and some decent 20% like Byrons Original, Odonnels, ect. Some that is tried and true. i actually have had good luck using Traxxassssss Topfuel in the 20% brand. but i know others that hate it. imho, stay away from Blue Power or Monster Fuel. i have had and seen more inconsistancy in that fuel than any other locally available here.

put one head shim on it!! that alone can make a big differance. and considering your currently on 10% nitro, going to 20% or even 30%, it should get a headshim anyways prior to the re breakin.

drop in a new plug like the OS 8 or even a McCoy 59. ( both of these plugs have always been decent imo)
if you can find out the stock needle settings that will help alot.

i agree currently it sounds as if your L needle is pretty rich.
but once you move up in nitro percentage, you ll have to turn the screws anyways.

airleaks, if you have any which it sounds like you may have, will certainly cause early greying of hair and massive amounts of cursing until you locate them and get them fixed.

Fwiw, I'm not familiar with the mill you have, but if worse comes to worse you could just buy a new mill.

the Mach 427 that comes in the Losi 8 and 8T RTRs is a great mill for 150.00
GL and keep us updated.
T
 
its not that I'm stingy, but 20% is expensive. wont 15% do?

which reminds me, how longs should a glow plug last, and same with an engine, along with any other high maintenance or high cost susceptible parts?
 
A glow plug can last 10 minutes, or 2 gallons. They can be wierd. I always kept a few handy, cause you run out of plugs, pack up and go home.
Also, the same with an engine...
Too lean, you can blow it up in a minute. But my guesstimate, and engine can go 4-7 gallons of fuel.

My approximations.

Good luck man. And welcome to RCNT
 
These little engines are made to run on 20% at a minimum. They can go higher like 30% or 33% if you go Traxxas. If you are not experienced in making your own home brew, I would stick to the 20%.
 
It Works!!!

IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!



just had to let everyone know, it works perfectly!!!! i found a few things on the way as well which I'm proud of. (the only thing I'm not proud of is that when i took the engine completely apart, there was a little, tiny bit of rusting under the piston, and around the balancer, really embarrassing when i think about it.)

but thankyou to all who has helped. that baby purrs like anything. but to reiterate what has happened,



IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!
 
So, I take it, it works?



Glad to hear you got her all sorted out.
 
IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!



just had to let everyone know, it works perfectly!!!! i found a few things on the way as well which I'm proud of. (the only thing I'm not proud of is that when i took the engine completely apart, there was a little, tiny bit of rusting under the piston, and around the balancer, really embarrassing when i think about it.)

but thankyou to all who has helped. that baby purrs like anything. but to reiterate what has happened,



IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!! IT WORKS!!!

LMAO...
Get back to us and let us know if it works.
 
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not sure if i have a problem... lol ill check it out and get back

no, no, its fine i though the radio problem came back. it was only low batts. hahahahahaha gave me such a fright i took apart the whole radio system before i tested the batt voltages... geez, i think i really am pathetic.
 
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thats right it works, and sounds nice. i cleaned it yesterday without noticing anything, and today ran it for an hour or two.

now about my last reply; nope. no electrical problems. false alarm.

now heres the real problem; there seems to be either oil or fuel leaked just outside where the carby connects to the engine. there is also oil or fuel leaked behind (engine-side) or the fly wheel, and since i have a very dusty, clay backyard (dont worry, i clean the car very often) it sticks and i can see everything clearly.

i must mention that when i put the engine back together, i did put after run oil to lube the bearings, so it may be the cause the flywheel part. note that the leaks do not connect, and thus are seperate issues.

the carby does have an o-ring. i might replace it and see if it helps. fingers crossed for the flywheel being another false alarm... because i dont want to take the engine apart again!! (in a childish moaning tone)
BTW about my first complaint, the engine didnt have any leaks, it may or may not have been in result of an overly rich fuel and these abovementioned problems, but the sides of the engine are fine and dry.

I'm not going to clean off the dirt just yet today if anybody has anymore questions
 
thats right it works, and sounds nice. i cleaned it yesterday without noticing anything, and today ran it for an hour or two.

now about my last reply; nope. no electrical problems. false alarm.

now heres the real problem; there seems to be either oil or fuel leaked just outside where the carby connects to the engine. there is also oil or fuel leaked behind (engine-side) or the fly wheel, and since i have a very dusty, clay backyard (dont worry, i clean the car very often) it sticks and i can see everything clearly.

i must mention that when i put the engine back together, i did put after run oil to lube the bearings, so it may be the cause the flywheel part. note that the leaks do not connect, and thus are seperate issues.

the carby does have an o-ring. i might replace it and see if it helps. fingers crossed for the flywheel being another false alarm... because i dont want to take the engine apart again!! (in a childish moaning tone)
BTW about my first complaint, the engine didnt have any leaks, it may or may not have been in result of an overly rich fuel and these abovementioned problems, but the sides of the engine are fine and dry.

I'm not going to clean off the dirt just yet today if anybody has anymore questions

Ok I am happy that it works LOL. As for your real problem, did you properly tighten the pinch bolt and nut? It secures the carb to the crankcase. If you are going to take it apart, you might as well seal the engine up wit some High Temp RTV Silicone. Apply a thing layer on the carb just where it sits on the crank case. Little goes a long way but be consistent all the way around. Push it in all the way but do not tighten the bolt yet.Do the same to the back plate of your engine. Just where the backplate seats itself onto the rear of the crank case. Do not tighten till the 24 hours is up.

Let this dry for 24 hours. You want to do this right so do not rush and make mistakes. You do not want any of this stuff in the case.

Good luck.
 

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