So today i broke in the engine on my tamiya nitro force. I ran 5 tanks of fuel through it without going full throttle. every time i started it it started on the first time and ran great. i brought it in, then about two hours later i went out to use it again. it took a few pulls to get it started and as soon as i hit the gas it stalled. i started it again and let it warm up for about a minute and it took off fine. when it ran out of fuel, i put more in and when i went to start it again the pull chord felt stuck. if i slowly pull it up it takes some force but it will come out and the engine will turn over. if i pull it hard enough to start it its gets stuck and it feels like im going to break it before the engine turns over. Does anyone know what could be wrong? Id like to get this fixed tonight if possible, i am dying to use it.

ok so now i tried it again and the pull chord wont come out at all. its stuck.

heat it up with a hairdryer, this releives the internal pinch

it has that much pinch even after 5 tanks of fuel have been through it?

When i first got it and the first times i started it was a nice clean pull that didnt snag at all. and now its getting stuck a whole lot when i pull on it. is it possible there is something wrong with the engine

I really need some help with this. id like to be able to take it out tomorrow

You may have flooded your engine. Flip it upside down, tugg the pullstart for like 30 seconds just to make sure anyway. Now check if your glowplug + igniter is working 100%.

You might be tugging on ur pullstart and the glowplug isnt even lit up and all its doing is bringing fuel in and flooding the engine.

Engine sounds fine to me, most likely human error or simple inexperience

I got a few questions;

Try to crank it, but without the glow plug; if you are concerned about scratching the sleeve then spray a small amount of WD40 (just a quick burst thru the crown).

You must feel some pinching or resistance, but not tight. If it is still too tight even with the glow plug removed then I would open the engine and flush it clean with WD40.

Thats why it is recommended on brand new engines to strip them open and do an overhaul cleaning. Sometimes metal particles (shavings) are left from the assembly line. I am not saying that is the problem, maybe it could totally something else, but it could be.

When engines have excessive pinch I would heat them up with a hair dryer and crank them without the glow plug and pouring little by little WD40 or after run oil. Its kind of doing the break-in, but all manually at least to feel the engine cranking and spot any obstructions that could pass unnoticed if started with nitro fuel. I would do it for like a minute or more manually cranking, heating, oil, cranking, heating, oil without the GP.

Let us know how the engine "feels" when cranking it without the GP...


Good luck

ok i took the glow plug out and it feels perfect. i can pull the started and it feels exactly like it should. when i turned it upside down and pulled it some fuel came out. so im sure that the engine was just flooded. thanks a lot.

Never leave any fuel in the engine. If your tank runs empty, follow up with a few more PS cranks to burn out fuel residue inside the engine and left on the fuel lines.

During break in place the piston on bottom dead center, at least for the first 10 tanks or so. Remove the GP and move the flywheel until the piston is at the bottom. Mark a notch on the FW so you know where BDC is. It is not really mandatory to do, but any little bit will extend the life of your engine. I am glad you figure it out...

Happy Rcing

I will definitely will be burning some nitro fuel, its nice here in Nor Cal.

Ok, i am starting to get frusterated with this whole nitro thing. I love the car when its running but every time it starts running its something new. I cleared out the fuel from the engine and it started right up perfectly. as soon as i hit the throttle it stalled. started it up again, touched the throttle and it stalled. so i started it again and let it warm up for about a minute and it took off fine. about halfway through the tank it stalled out again. finally got it started drove it a little then it stalled again. with less then 1/4 tank left it stalled and the only way it would start is it the throttle was open a little bit, then as soon as i was not giving it any throttle it would stall out. i need some help with this.

Its just ur tuning dude... dont let it frustrate you. Your LSN is either too rich or too lean. Have a look at the tuning guide it might help [link]http://www.rcuniverse.com/forum/m_5517128/tm.htm[/link]

Sounds like your high speed needle is a tad rich also, turn it in 1/4 at a time, you wont hurt your motor, you need to get some heat into it.

am i missing something because there is only one needle. not a HSL and a LSN. In the instrustions it only mentions one, and they call it a Needle valve. there is also a screw to adjust the idle. thats not it is it?

im not familiar with tamiya nitros so you might wanna double check around the carb area. The highspeed needle is the one that usually sticks out of the carb body and the lowspeed needle is usually mounted into the carb itself

You might have an old single needle type carb like old school engines.

Thats why many people get out of nitro real quick without giving it a chance. I even had a friend who thought that this is like a regular car, dump some gas and lets go.

Start the car;

Drive it slowly up and down on the street to warm it up.

Warming up is never done with the vehicle on idle. Then after a minute or so hit it full throttle a few passes letting go of the gas.

If when accelerating the car feels very slow to reach maximum speed, then its too rich.

If you accelerate and it wont reach full speed, like if something is missing which in fact it is, then open the needle just a tid bit. Another way to know is the engine is getting hot very quick (it needs more gasoline). If it does not reach maximum speed, but feels cold then it has too much fuel.

Ok, then lets go and do a few more WOT passes and bring it back, wait about 3 or 4 seconds and then pinch the line... if it stalls real quick like right away then it is too lean. Another way to tell when is too lean is after a long opass at WOT the car emits a high pitch sound like it is hanging in there accelerated and then after 2 or 3 seconds it comes back down.

If you are not sure about the lean or rich; then just do one of the two, close the needle or open the needle for about one to two full turns and depending if you see progress or not then you know you are going the right direction.


It seems you dont have a temp gun, or try the spit test on the crown or just simply touch it.


The main key is to touch the crown and try to see how temperature fluctuates. Temperatures that spike dramatically are signs of a lean mixture. An engine that is warm to the touch even after many WOT passes means it is only at 50% power or too rich.

Pay attention to the sounds, intermittent sounds after WOT means lean, inconsistent idling and a high and low pitch means lean. All of this may seem confusing; you will see be very patient once you get it dialed its going to be a piece of cake and the tuner of the park for everybody else. During all this learning process dont let the engine cook; very hot temperatures on a barely broken in engine is a recipe for disaster.

thanks a lot for all the help. i am taking it out in a little while this afternoon. ill let you know how it is.

which tamiya motor is it we are talking about, what size? If its the 32 it is an ofna make. I've never seen a car motor with one needle. Unless its a rotary carb, not a slide valve.

its a 1/10 scale buggy has the tamiya frs.15 its a slide carb has one highspeed needle and idle screw my mate used to have the tamiya nitro thunder same engine it is a bugger to get running right even with expierence thw whole car give him nothing but bother., he sold it in the end and got 1/8 buggy

Yeah im pretty sure that is the engine in my car. I got i running really nice this weekend. It took a little while but once i got it right i was able to run about 6 more tanks of fuel through it without any problems at all.

Engines flooder pull out glow plug

The needle bearings are probably getting wedged on to the starter output shaft ,if the o-way is in the pullstart housing itself ,then pull it off
an put a couple drops of oil in the o-way bearing.

Also,your engine is still tight ,you can loosen up the glo-plug a little before you start engine ,the once it starts up ,pull igniter off
an tighten it back up while engine is running. This helps relieve the pressure on the starter on first start up,acts like a compression release!

Necrobump! . Not sure if Maggie678 is a bot or not, but a 9yr old thread revived with a 6 word reply makes me scratch my head..... Much like the goof balls that suggest using airplane fuel in RC car engines and using compression gauges to determine their condition....