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Old 11-08-2008, 04:21 PM   #1
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Default Nitro RS4 MT won't fire up!

Hey guys,
So recently i unfroze my nitro engine. It's been sitting around for about 5 years but before i stopped playing with it, i only put about half a gallon's worth of fuel through it. The glow plug/Glow starter both work. The glow plug lights up just past the orange color. At first the nitro wouldn't travel through the tube for some reason, then i cleaned out the tank and tube and finally got it prime correctly. So i primed it so that the fuel just hit the carburetor, put on the glow starter, and kept pulling the pull start. But nothing happens, it won't even start for a split second. Then i thought it was flooded so i emptied the tank and removed the glow plug, and start pulling on the pull start with the car upside down. After about a minute's worth of that i put the glow plug back on and refilled the tank. Did the same thing as before, but still nothing. What's going on here?

P.S. (This is the Nitro Star 15FE engine, it came with the HPI Nitro RS4 MT).
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Old 11-08-2008, 08:51 PM   #2
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anyone?
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Old 11-08-2008, 09:54 PM   #3
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I also have a RS4 MT that took some care & feeding before getting it tuned. A couple of things to check:

- The carb has no low speed needle, just HSN & idle adjustment. Make sure your idle screw is set so there's a 1mm gap (about size of edge of credit card) at neutral and/or when brake is engaged.

- The manual for the MT says to set the HSN to 3 turns counter-clockwise from full closed which is incorrect and *way* too rich. The troubleshooting guide in the same manual has the correct amount: 2.4 turns from full closed. Adjust HSN lean or rich by a couple of clicks as needed for optimum operating temp range (220-260F).

- If your fuel line was clogged just replace it. You still may not have enough flow. Same with your exhaust->fuel tank line. If you don't get enough backpressure the fuel isn't getting into the chamber well enough to stay running.

- Double-check your fuel tank for leaks. Same issue with pressure & fuel flow.

- Take apart your carb and ensure there are no deposits or other gunk blocking fuel flow into the engine.

- Unless you are getting a lot of drainage from removing glow plug and dumping it out, it doesn't sound like you are getting hydrolocked.

- When you say you "unfroze" your engine.. was it not moving at all/stuck completely? You may want to check your piston ring and fit to make sure you don't have a leaky chamber. If the fuel isn't getting compressed at TDC it won't ignite properly.

If all those things are checked or done, prime your engine with a couple of rotations on the starter with your finger over the exhaust hole. This is will force fuel into the line. It should (hopefully) start right up afterwards.

Hope that helps.
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Old 11-09-2008, 10:46 AM   #4
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Thanks for the response Amoeba, really appreciate it. I checked the fuel tank and lining by submerging them underwater in a sink and seeing if any air bubbles come out of the wrong areas. It was completely fine. When i took out the glow plug and tugged on the pull start with the car upside down, nothing actually came out. So my guess is that the carburetor is clogged, i'm gonna have to take that thing apart later. Oh and yea before i unfroze the engine it was completely stuck, wouldn't even budge. But i don't think there is anything wrong with the moving parts since i feel a lot of pressure just before the piston hits TDC.
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