cmullins

Ok, this is probably the point where most newbies give up and sell out but I have made up my mind that I'm not going to do that. I have put so much money into this thing I can't turn back now. I have a RC10GT that came w/ the AE .15 (RTR +). The engine has ran flawlessly up until a few days ago. I will try to give as much detailed info here as I can so bare w/ the long post.

The problem is I can't keep the engine running at idle now. It will idle for about 8-10 seconds as soon as I start it but then when I give it throttle and run it for a few minutes it will die as soon as I let off or just 1-2 seconds after. I have adjusted the low speed needle until it gurgles out and dies (too rich, right?) and I have also adjusted it until it leans out and dies (both at idle). I have it now at about the factory settings. It is very hard to start and the only way I can get it to start is put my finger over the exhaust pipe and pull the starter 6 or 7 times and then remove my finger and it fires up. It will then run fine as long as I stay on the throttle but if I let off or especially hit the break it dies immediately as if it is getting NO fuel. Sometimes it even acts as if it leans out and dies as soon as I let off the gas but the high speed screw doesn't seem to affect the symptoms. It is still smoking and doesn't sizzle water too fast so I don't think it is too lean. Could I possibly have an air leak? If so where do I troubleshoot? The only changes I have made lately is the type of fuel I run. I went from Trinity Monster Horsepower to Blue Thunder because LHS was out of stock. I did have to tune the high speed needle a little when I switched the fuel but it was actually doing this a little w/ the Trinity fuel but has slowly progressed to a big problem the last two times I have ran.

Please help me get this thing lined out. I was thinking of running my first race this coming Saturday and now I am about to give up and throw this thing. If you need more info than what I have given then just let me know.

packfan88

My Feedback: (2)

when you say you get it to start by putting you finger over the exhaust, what that does is "prime" the carb.
thats how most work, since the plunger thing on gas tanks usually fails and its replaced with a tank that doesnt have it, or its removed by a method you can search for here on rcu. sounds like that is how your priming it since you said it wont start it you dont do that. thats fine to do that, but if your gas tank has a plunger on it it might have gone bad and caused a leak.

trouble shoot your air leak by
1 replaceing the fuel line...its cheap enough that you can do it with spending a lot of money
2 take the gas tank off - pinch one hose and blow into the other to fill up the tank with air while its submersed in water...liek ina bowl or bucket.
3 check your fuel filter the same way as the tank, cause some leak
4 take your carb off and seal the connection point where it meets the engine block.
also check your exhaust for leaks while your at it. check these connections
bloack to the header.
header to the pipe
cheak the head itself for no loss of compression thorugh the sides of the glow plug and the botls that hold it on.

when you have your car off, hit the throttle on your radio and see if the carb opens up wide.....then see if when you full brake it closes but leaves a moon shaped space the thickness of a credit card. if not adjust it.

i dont know if you did this or not, but make sure when you change fuel you take it easy for a coule tanks to allow the engine to work in the new lubes and stuff of the new fuel.


you said when you do get it started and you run it for a few minutes, it stalls when you let off the throttle. you sure its not too hot?
check it.
does it began to happen at the same point of fuel consupmtion? 3/4 of a tank? 1/2 a tank? etc.....are you getting a lot of air bubble in your fuel when the tank gets less than full? if so try to make your exhaust to gas tank line longer.

finger are tired....let us know

cmullins

Great info Packfan. Others feel free to help too. The more info I have the better. Packfan, the reason I brought up the priming is because I have never had to do that before. I have always just had to trim the throttle open a little to get it started and then back it off to run and it idled perfectly. I had actually gotten remarks on how great it idled and ran. So you think my tank may just need to be replaced? I will check that first. As for the bubbles in the tank, I did notice there were some yesterday when I gave it throttle but I haven't modified the tubing any from stock and never had the prob before. Would a leak in the tank make it bubble too? And to answer your last ? about the fuel level, it does it regardless of fuel level. I did lean the settings first thing when I switched fuel and that goes against what you said about running a few tanks w/ different fuel. When I switched it ran bad like it did when I first got it and was breaking it in. Should I richen back up and just tune from scratch before I troubleshoot for air leaks? Thanks again

-tommi-

"It will then run fine as long as I stay on the throttle but if I let off or especially hit the break it dies immediately as if it is getting NO fuel."
It sounds to me that the throttle brake linkage isn't quite rightly set. When you hit the brake, the carb should stay as it is when it's at idle. Try adjusting the collar so that when the brake is applied, 1. the carb should be in idle position 2. spring should not be compressed completely.
Maybe...another possibility could be the carb opening when idle is too small?
Just my 2 cents...

BUGGIES_R_US

Dont discount settings just because they USED to work right.

I get the feeling that maybe you hit the car or something like that happened?

I dont know much about air leaks.. but a set screw or throttle/brake linkage problem could definitely do this!

ram

William H

Can the transmission run out of the Rc10gt?

packfan88

My Feedback: (2)

no but a a chicken can run out of the hen house.

Homebrewer

My Feedback: (8)

Basic Rule of Troubleshooting glow engines:

#1 Replace the glow plug with first sign of trouble. This could save you hassle in messing with your settings.

#2 Use a fresh gallon of fuel (new, never opened).

#3 If 1 and 2 dont' work, check for airleaks in fuel lines, carb, engine head bolts, etc...etc...

I had an engine giving me fits at full throttle. It would idle all day long, run great at 1/2 throttle but die after 30 seconds at full throttle. It turned out a replacement glow plug cured my problem without having to touch anything else.

Andy

PS You may wish to blow out your carb and make sure mothing is clogging it.

cmullins

Thanks guys for the reply. I haven't got to work on it any the past couple of days but hopefully I will Thursday. Andy, I did change the glow plug after fooling w/ it for a while so it has a new one in it and I am running fresh fuel as well. I will try and diagnose an air leak, go back to factory needle settings and check my throttle brake linkage and let you guys know what fixes it. Thanks again

William H

DOES anyone know if the transmission run out of the rc10gt?

nbraunstein

If its legs are long enough I suppose it could run pretty fast out of the rc10gt. Ya never know what kind of energy bar it had for breakfast.

William H

What?

packfan88

My Feedback: (2)

if you didnt read my reply about the chick or his reply about the legs, it means

WHAT THE #$@% DOES THAT MEAN?
your asking us a question that makes zero sense. can a transmission run out of a car?*** does that mean?

nitroman88

My Feedback: (5)

That would be funny if the transmission came out "run out" of the car.

William H

CAN THE TRANSMISSION QUIT or BREAK I DID NOT MEAN LITERALY RUN OUT!!!

nitroman88

My Feedback: (5)

There are alot of parts to the transmission, what part do you mean??

William H

Well Bud,I mean like isn't there a little transmission part in the back of the engine and the spur gear and all the other stuff? Like in the front of the battery pack?Do you know what I mean?

William H

Can you tell if the engine is going fast by the way it sounds and or the way it acts?I mean to lean?

nitroman88

My Feedback: (5)

yes, if it is too lean there will be minimal smoke and the engine will rev scary fast.

rccartips

For me, if the engine sounds like it is running out of breath, hollow, wheezing, then I know it is lean.

If it is rumbling, powerful throaty sound, then it is rich or good.

Better yet, check for tons of blue smoke coming out of the exhaust. More means rich setting, less or non means too lean.

William H

Can it make a clicking sound?Or is that the clutch raddling AND You turn it clock wise to lean it right?

neap38

hey i think i sorta have/had the same problem as one of u guys ... every time i give my car some throttle it will gofine oor a thew secondes then just cut out i have to spare glow plugs im gonna test them now see if it makes a difference... i hope it works other wise im going to be pissed... ive all ready messed it up byt rying to tune it ... when before it was tuned my a professional and ran realy well.. o well

be back in a min ill tell u if its made a difference.