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Old 07-07-2008, 06:38 PM   #1
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Default running like crap & overheating

Long story warning. I'm trying to give all the details, so if you can muscle through the story I would appreciate the help.

Ok, so yesterday I was able to run a few tanks though while cruising through the backyard. Actually learning how to control the truck around some trees. I broke a front universal so that ended my day, plus it started to rain. RWD monster truck in the rain = donuts

So I bring it back to the porch do my usual of running the engine and dripping 5 or 6 drops in the carburetor and let it burn up the oil, make a nice little smoke show, the whole shebang. In doing this it sits on a stand and it may have over rev'd but i don't think it would have been any higher than it has gone before. Then I pull the plug put a few drips in the carb and a few in the plug hole and spin it over by hand. Then put an old glow plug in there to keep dirt from getting into the bore.

Fastforward to this evening. I replaced the dog bone, tightened everything up and took it outside. I put in my normal running plug, get it to fire up. And it doesn't really want to stay running too well at idle. I adjust the throttle trim to a hair high and it stays running. I start running it, figure maybe its just cold and needs to warm up. It runs like it is fat and it doesn't like to stay running. I figure the plug may have finally bit the dust, so I changed the plug to a brand new plug. Still doesn't really want to stay running and every now and again it runs like it is fat and doesn't have any power.

I finally check the temp because I did fatten it up a little yesterday to keep the temps in the low 200's and it was already up to 250 - 260 even though I hadn't really done anything, just a couple quick blasts out to a tree and back (not very far, couple hundred feet MAX total). I fatten up the high side a little and it stays up around 260, and then I figured since I haven't really been at wide open much maybe the low side is lean. So I open it up a bit. I run it around again, and its between 260 and 270. All the while it still doesn't want to stay running and every now and again it has zero power.

So I drain the extra fuel and take it in. I take the tank off and it, as well as the fuel lines, are free flowing. I did clean the filter with some fuel right out of the can, but there was hardly any dirt in it. So I get to the motor, I figure maybe because of the orientation of the exit pipe the extra oil may not be coming out of the exhaust, but there is only a little in there. I take the remainder of the exhaust off and find that the silicone coupler is ripped, maybe this is the problem? I continue to take the carb off and make sure all the passages are unobstructed and they are plus all carb seals are intact.

Questions:

-Is the problem mainly going to be the exhaust coupler?
-Or should I look deeper?
-Rather than ordering a new coupler (if I can even get one) for the Torq 21 from Tower Hobbies, is there another that will fit?
-Or will I just need to try some till one fits?
-Could the crankcase be full of oil?
-Did I bore you enough?

Thanks for the help.
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Old 07-07-2008, 06:42 PM   #2
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Any exhaust coupler made to fit .21-.28 engines will fit. I know that GS Racing makes them.

I would try the coupler and then go from there, you do mean the coupler that connects the header to the tuned pipe right?
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Old 07-07-2008, 06:53 PM   #3
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You didn't leave the fuel can or fuel bottle out in the rain did you? Moisture in the fuel will cause the exact symptoms you described.
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Old 07-07-2008, 07:05 PM   #4
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I mean the silicone piece that goes on the exhaust port of the engine that seals the exhaust to the engine. I can take a pick if that helps.

The fuel was outside while it was raining, but unless I am filling the tank the bottle is closed. Plus my patio is covered by the balcony of the apartment above me. So the fuel bottle will only be open for a minute or two at most. I know all to well how fast methanol will suck up water from drag racing.
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Old 07-07-2008, 09:19 PM   #5
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Lightbulb seal

if it was the seal it would sound louder than normal and run crappy but not like you make it sounds do you have a fuel filter on the fuel line ??? it might be clogged and restricting the fuel flow to the carb .check all the header screws and make sure they are snugged down ..replace all the fuel lines and the seal and try again reset the motor to factory setting for breakin and re tune .
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Old 07-08-2008, 04:29 AM   #6
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Like I said in my original post, I cleaned what little bit of dirt was in the fuel filter out with fresh fuel and "backflushing" the element. I was thinking of replacing the line, since it is 4 years old.

So at the hobby shop today I will be getting a new exhaust seal, fuel line and a new fuel filter (because it too is 4 years old, and thats a good run for a filter in my book)
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Old 07-08-2008, 11:20 AM   #7
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Bump for more views before I head to the Hobby Shop.
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Old 07-08-2008, 11:33 AM   #8
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Quote:
Originally Posted by racer12306 View Post
Bump for more views before I head to the Hobby Shop.
An exhaust leak can cause the motor to run lean, have no power, and get hot.

A clogged fuel filter can cause the motor to run lean, have no power, and get hot.

An air leak around the carb can cause the motor to run lean, have no power, and get hot.

A leak in the pressure line from the pipe to the tank (assuming you have a setup that uses one of those- some 10th scales don't) can cause the motor to run lean, have no power, and get hot.

A leak in the fuel line from the tank to the carb (either before or after the filter) can cause the motor to run lean, have no power, and get hot.

So... your symptoms could be any of those things. I would replace the exhaust seal, the fuel filter, and all the fuel line, see if that resolves the problem. If not, remove the carb, apply a little bit of silicone around it, and reinstall it. See if that fixes it. And like was mentioned... some fresh fuel may be in order.
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Old 07-08-2008, 11:40 AM   #9
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Thanks, it's good to know I was on the right track. I know a fair amount about full size engines, but these little glow engines are a whole new world.

I've actually gone through this quart pretty fast. It's only been opened a week or so. I only buy in quarts because I don't run very much, most of the time. It is the Traxxas fuel, which I don't like the cap on the can.

I'll replace all that stuff and if it still isn't happy, I'll crack open a new bottle of fuel.
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Old 07-08-2008, 12:04 PM   #10
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Originally Posted by racer12306 View Post
Thanks, it's good to know I was on the right track. I know a fair amount about full size engines, but these little glow engines are a whole new world.

I've actually gone through this quart pretty fast. It's only been opened a week or so. I only buy in quarts because I don't run very much, most of the time. It is the Traxxas fuel, which I don't like the cap on the can.

I'll replace all that stuff and if it still isn't happy, I'll crack open a new bottle of fuel.
If the fuel is only a week old, it should be just fine, unless it sat in the hobby shop for a VERY long time... and as long as you kept it sealed. It shouldn't be a fuel problem.
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Old 07-08-2008, 05:55 PM   #11
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So apparently the Torq 21 is special. I got an exhaust seal for a .21 engine, but it is too small. The header is way too loose on the engine. I tried doubling them up, since it came in a 2 pack, but that was too big.

This is the one that came on it: http://www3.towerhobbies.com/cgi-bin...EARCH=dtxc8257

Anyone know of a seal that will match that size and won't have to be ordered from Tower. I really wanted this truck running this weekend. I was going to bash it around the Jeep pit at the Chryslers at Carlisle car show. But I'm not going to pay to next day a seal that only costs ~$3.

Can I get one for a .28 engine?
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