Basically dug an old Nitro RC car out of the cupboard with a view to getting it running and either using it for a bit of a laugh or just selling it.

Having loads of trouble getting it started and knowing theres a couple of RC car people on here hopefully someone may be able to assist!

Ive renewed a few bits that were clearly broken, i.e pullstart, bodyshell etc and bought a gallon of Nitro fuel as the fuel in the tank was very old.

After charging the glow igniter for 10-12 hours I gave it a bash, heated the plug up and gave it a couple of pulls and nothing! Tried it loads of times since and cant get anything out of it, sounds like it should be ready to go but just wont fire!

Things ive checked so far and I believe can be eliminated are as follows:

Glow Plug = Tested out of car and glows brightly (although not to the very tip of the coil, probably glows to 1 coil before the tip!) Ive also tested it by wiring 2 x AA batteries in circuit with the plug, this also caused the glow plug to glow so the plug seems ok!

Glow Starter = Charged 2/3 times in the past week, tested on glow plug and as mentioned above the plug glowed fairly brightly!

Fuel = Fresh fuel in the tank, and plenty of it! Fuel seems to be reaching carb/engine as turning the car over with the plug out causes fuel to spray out of hole in top of cylinder/heat sink!

Engine = Looks ok and turns over ok, piston moves as expected. The only thing is the top of the piston looks a bit tarnished but certainly doesnt look like its worthy of causing it not to start!

Now im a bit stumped as to what to do next, im toying with the idea of buying a starter box to try and start it like that but would prefer to eliminate other issues first as ive got a feeling I could fork out Ł50/60 to be in the same boat!! The only thing I can think it could be is some sort of air leak, not sure how "air tight" these should be but when I blow back down the fuel pipe (from exhaust end) it seems like the lid of the fuel tank is not entirely tight, if I apply pressure to the lid it seems sealed but if not I can hear air leaking from it, with that said it does seem to flow fuel into the carb however occassionally air bubbles form in the fuel line!

Anyone got any ideas?!

 

What motor is it fella,engine size, fuel % in it and heat of plug??

Tried heating the old girl up with a hair dryer 1st, get it hot then try it, with a touch of trim..

Also if possible slightly open the throttle using the trim on the reciever, could just be the idle gap in carb is too small or too big. With servos all on it needs to be 1-1.5mm gap with the trim set at neutral("0").

Could be air leeks, need to be propper air tight, esp round crankbearings, exhaust mainfold gasket, head shim(if fitted),...Probs needs factory settings re-set for carb lsn/hsn/idle and mid if fitted.

Oh and the plug should ideally ignite alt way to tip of coil wire.

If completely stumped post here http://www.google.com/url?sa=t&rct=j...e9wxzsjhQrJ_2g

Good bunch of lads

 

might well be crap in the fuel lines/carb..

get some carb cleaner or something and blow all the fuel lines thru with it, wind the carb needle out a bit and blow a load thru that too with the throttle open (might need to hold engine upside down so it dont flood the engine lol)

when that fuel is left in the lines etc for a long time, it turns to a sort of jelly lol.,

 

Right well its an old Tamiya car (Nitro Thunder) that runs a .15 motor (2.5cc)

Will have to double check the fuel but I think its 20%......

The plug has No.3 on the side of it so I think that indicates what sort of plug?! I have seen videos of these that are smoking they are so hot, mine doesnt so I may just buy a new one just to be sure its not that! It definately glows but like I say, not to the end of the tip even when wired up to the AA batteries!

I think its pointing towards an air leak then, something that is mullered that I didnt think would effect it massively is the exhaust manifold gasket! That is totally knackered, its ripped and therefore when fitted it rucks up inside the end of the manifold and doesnt fit that well so that could well be an issue! I think ill buy that, a new tank and some fuel line and will have another go!

 

Well ive already cleaned the fuel system out, whilst waiting for the replacement pull start i took the opportunity to strip the whole lot and clean it, soaked the fuel tank and rinsed it several times before drying it out, same with the fuel lines! So all that should be ok! It definately gets fuel to the carb/engine as when I pull the pull start with no plug in it shoots fuel out of the top of the engine which as I understand means the fueling side of things works ok?!

Its so frustrating as I know its pretty close to running, the only thing I cant quite get my head round yet is the carb settings!

 

do it even sound like it wants to fire??

as in when you pull it over it revs slightly and dies straight off?

Are you getting fuel out the exhaust?

 

Well in between times when its flooded, it has had a couple of moments where its sounded like it may fire but nothing any more than that!

Ive signed up on that website you linked me to and ive posted on there asking for the carb settings, may well take some pictures of the car in various stages and possibly record my starting attempts so people can cast there opinion on what it may be!

Doesnt help that the glow starter ive got only seems to hold enough charge for 7 - 10 attempts! Once that dies I know theres no way of starting it so usually just gets put away again! I did make a glow starter using the AA batteries but its a right slag to get on the plug with it in situe so I cant really use that!

 

Sounds like an air leak check the gasket on the backplate where the starter is and the o -ring under the carb a tiny amount of silicone may help on both, then just check the head bolts and lastly the copper washer on the glow plug, failing that try a new glowplug and check the fueling.

 

Well I think I may have found the cause, although I have still got to get the bits and get it rebuilt before I can try it again!

Basically took the engine out last night to leak test it and straight away I noticed something that looked a miss! Not only is the exhaust gasket (rubber/silicone top hat style gasket) absolutely destroyed, but it appears that in a previous rebuild someone has failed to replace the head gasket!!

Cant believe I havent noticed before but it certainly doesnt appear that there is a head gasket fitted, I assume this is almost definately a cause for it not starting and would explain alot really!! I assume the gasket would just sit between bottom and top ends of the engine, it wouldnt be fixed as such would it?!

I have since found a place which sells the gaskets so ive ordered them up, also ordering a new glow plug and glow starter as I dont think either of mine are working properly plus its one more thing I can eliminate!

 

Nitro fuel is hydroscopic which will attract water it is also corrosive on metal which is why you shouldn't leave fuel in them, i always used after run oil. This may have something to do with why it won't start.

 

Mmmmm well it was sat for years with a tiny amount of fuel in the tank which turned out to be more like a gel when I removed it! Had to soak it in hot soapy water before rinsing/drying it out so get it all out!

I have run new fuel through it a couple of times and it doesnt look too bad inside the engine so hopefully it will be ok!

 

Sorry Neil how old are you???? next you will be getting your action men out the loft hahaha..

 

yup missing the shim will shit it right up

If still nothing once you've fitted it all up post a vid up, hell of alot easier to diagnose poss faults

Keep us posted

 

This may be irrelevant but try screwing the main fuel mixture screw fully in til it stops then turn it out 3 turns (normally has a brass outer on)

 

Action Men? I think thats probably more your cup of tea isnt it? Or was that Barbie?!

 

Ordering the bits this afternoon so should be able to have another go for the weekend!

 

Also try filling the carb with fuel. i can always start mine with this method

 

make sure the exhaust is also empty of fuel..

One of my old helicoptors was a bastard for flooding and you'd have to take the glow plug out and exhaust off to drain the cylinder and exhaust before it would go again..

I presume that it was running before without a HG in it. If it's designed to have one then so long as it's sealed then it will only raise the comp a bit, should not stop it running..

I think most of the above suggestions should get you going..

hth

 

Well thats just it, ive had it in my garage for years (probably 5-7 years at least) and its never run whilst ive had it! I took it off someone as a bit of a payment for something and it was in bits when I got it, rebuilt it to 90% complete but never got it running!

Only in the most recent efforts have I actually tried with any serious effort to get it started, i.e actually buying a pullstart and fuel for it! LOL!

It certainly should have a HG, it shows one in the instructions for the engine so id assume it should be there!

I think its a combination of a few things, HG and Ex gasket and also glow start/glow plug! Will try once more with the existing engine and if it doesnt run this time I might just stick a .18 lump in it!