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Help! Nitro Labour of Love


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Help!

So a nitro enthusiast very sadly died in his prime, and his wife was clearing out their garage and I’ve inherited an old Traxxas nitro and a box full of parts.

 

A few years have passed and now I feel such a drive to honour his memory and get the thing working again - plus I think both my sons and I would absolutely love using the thing. It’s 30 years since my old battery Tamya and I always wanted but could never afford anything petrol!

 

Problem is I just can’t get the thing started. I know forums are full of newbies like me asking stupid questions so I’ve tried what look like the basics first from a bit of research.

 

The flywheel spins when I use the battery starter but the petrol engine never “catches”. I attach a video.

 

So I’m using a brand new glow plug and wire that I ordered as spares. I’ve got some fresh 20% fuel. I’ve got 3 fully charged starter batteries. Both lights shine when I use the starter. My needles are set to their factory positions and I’ve tried adjusting the upper one anticlockwise a bit. 
 

I can see fuel getting into the engine and I can feel air coming out of the exhaust. I’ve applied a little throttle when starting. I’ve cleared and oiled the air intake sponge.

 

What else can I try? I would be just so amazing to hear the engine roar into life after spending hours tinkering! HELP!!!

 

PS other observations. When I first got it out the flywheel was stuck and nothing turned at all. I think it was “TDC” and maybe a little stuck after time but I got it turning again with a screwdriver on the flywheel and some wd40.   It did catch once very briefly for about 2 seconds before quickly fizzling out but never again after hours of trying. The electrics seem okay and I can see the throttle responding and the air hole behind the air intake getting bigger and smaller when I apply the throttle.

 

 

 

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Wow that’s great advice thank you. Really appreciate you spending the time to reply very kind. Forgive my ignorance petrol vs nitro. I took out the glow plug and touched it to the side of the motor and passed current though it a got a faint glow - should it be red hot?

 

It’s a 3.3 motor and a “super heavy duty traxxas glow plug” that said on the website was compatible with a 3.3 engine.  To clean the connectors I’ve bought a new wire that attaches to the top of the glow plug - presume you mean where the other wire to make the circuit attaches to the engine?
 
On the fuel pipes then there looks to be some unused plastic piping of the same diameter in the box of spares so I’ll give that a go. Is the most important pipe the one that passes from tank to engine (rather than the one back from the exhaust to top of tank) or is it both? 
 

The throttle does alter the gap in the carb slide and when idle there is a small gap so that sounds fine?

 

Thanks again for your help will have another crack at this and report back! 

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Try recharging the glow igniter and try again when its fully charged as the glow plug should glow fairly brightly 

If its still the same then try a new glow plug

all the pipes are important 

the 1 from exhaust to tank provides pressure to push fuel from the tank to carb 

and 1 from tank to carb supplies the fuel 

if theres a fuel filter on the carb pipe make sure thats clean as well

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Glowplug should get a glow like this:

 

images?q=tbn:ANd9GcTPzMEB0hPFhm8Zx1yKeMp

if it's working well. The wire setup on this should be taking ( probably 6V from the starter) power to the central tip of the glowplug. The other end should be getting an earth connection from somewhere on the truck body or engine.

 

I home brewed a setup like that for a nitro RC rally conversion I built. It was a pain to take the body off when I wanted to start it, so I rigged a glowplug ignition using a small battery box with an on/off switch and the motor used a roto-start. Hooking the power to the glowplug was reliable, but it needs a good 'earth' path. Normal glowplug ignirtors contact the outside of the glowplug for this, but as it's screwed into the head...actually anywhere on the motor worked fine.

 

I think from the video that the motor is nearly firing...it's just that last little issue. Once you get it running and tuned, you will find it a lot easier next time. It's sulking after being woken up.

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For starting rasie the car off the ground using a stand of some sort, so wheels can freely spin and raise the idle rpm, either by adjusting trim of transmitter or by idle screw, with carb gap greater than 1mm, or just use transmitter and squeeze throttle whilst starting. I would also try leaning the high speed needle 1/2 turn clockwise from factory.

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Hi,

 

So have been running on a stand bar half throttle and have checked idle gap also looks okay.

 

Have tested batteries and two seem to give decent voltage.


Have checked compression and plenty of pressure on my finger stuck in engine  as it turns.

 

Think it’s the glow plug circuit in some way? I have cleaned connectors but 2 brand new glow plugs still do not seem to be glowing. I’ve have checked for glow by running starter current through glow plug taken out of the engine and touching side of the engine but nothing. Then tried connecting it straight to the wire that was attached to the housing and still nothing - see the video - when i connect and disconnect the wire to the side the light goes on and off on the starter so I’m must be making a circuit? Not sure what else to try? 
 

Was going to hold off on attacking the fuel pipes until I got a glow! 

 

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One relatively simple thing to try would be ditching the glowplug igniter setup you have and trying an external one.

I don't like just suggesting folk spend moneyto fix stuff if other options exist, but I think if you can;t find a fault with the setup and it isn't getting power to the plug, then something like this: 

https://www.modelsport.co.uk/product/fastrax-2100mah-glow-plug-starter-with-charger-27758

would at least allow you to disconnect the glowplug leads you have and just sstuff that on the plug ( after charging it of course...)

 

Something is very much not right with that glowplug circuit. Doesn't look to be lighting at all in the vid, or if it is, so little I can't tell. That won't start a motor.

 

Did you check the voltage across the power and ground leads? Doesn;t take much voltage. Most of the glowplug igniters I have are running off a single 1.2v cell.

Might also be worth checking continuity between the connection to the starter unit and the glowplug on power and ground sides. A bad connection or short could kill the power. Plus check the power output from the starter unit.

 

Actually..thinking on.. the setup I had for my remote start just used an AA battery. Grab one, attach a lead to the -VE end and earth that on the engine. Connect the +ve terminal of the battery to the lead going to the connector on the glowplug ( blue lead). Should allow you to direct power from the AA battery straight to the glowplug. I can see a connector in the middle of the blue wire...so pull that and hook the battery there. Then just run a piece of spare wire from the base of the glowplug to the negative end of the battery. Glowplug should light up.

 

If it does...then earth the battery on the motor somewhere, screw in the glowplug, hook the positive side up to the AA with the blue wire going to the positive on the AA pack. Plug in the starter wand and crank it.

 

This will let you seperate the starter and the glowplug. I'm thinking the issue is the starter wad not supplying power to the plug, as you seem to have checked everything connection wise.

Edited by Nitroholic
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SUCCESS!! Thank you so much all!

 

Here’s it whizzing around for anyone who’s interested. 
 

I’m so happy that we’ve resurrected an enthusiasts pride and joy. And I think I’ve got the bug now!

 

So the separate glow plug starter worked a treat! In the end it must have been some sort of issue with the ez starter.

 

It still burnt through two new glow plugs in about 5 mins so I’ve adjusted to be less “lean” for next time I get some new plugs.

 

Thank you so much everyone - you’ve all been very kind.

 

 

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