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Old 12-13-2002, 09:23 PM   #1
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Default need help

my 15fe engine has developed a serious problem. it now needs to be leaned way out to run. it used to run fine with the needle around three turns out from closed. now its more like 1 1\2 turns from closed position. it has full power at that setting, but runs way to hot. i think it may be an air leak that is causeing the air\fuel mix to lack air.. thus only running when leaned out. i have checked sever times for leaks, and havent found anything strange. any ideas what could be wrong? i got a new backplate already because the starter crank was loose in the backplate bushing.. didnt help. oh, and after being warmed up, the engine blips up and down in rpms spuratically. anyone had these symptoms?
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Old 12-13-2002, 11:03 PM   #2
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Check the gasket for the carb..Base and needle also, maybe the O-ring might have a tear in it.
Air leaks are hard to find so you might want to check the whole engine and reseal with high temp gasget sealer also change the fuel lines.
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Old 12-13-2002, 11:19 PM   #3
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Default .15Fe with a headache

Wahturi;

Make sure that one of the screws that hold the carb onto the crankcase isn't loose or missing. But it sounds like you may have overheated your engine one too many times and it only takes a few times to wear out the piston and sleeve. One run without the Air Filter will also ruin an Engine. A properly tuned and maintained HPI .15FE should last for AT LEAST 3 gallons of fuel. I have one now that is probably over 6 gallons (1-1/2 yrs old) and gets raced almost every weekend.
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Old 12-14-2002, 07:50 AM   #4
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well, does it sound more like a worn engine or an air leak? i jsut found one thing out, i have no head gasket. ever sincei h ad the car, i havent seen it. so i dont know if i lost it or if i just didnt get one.. but my friend got the same car as me at the same time and it runs fine. he also is missing his head gasket. when i take off the exuast, and turn the crank to position the piston under the exuast valve, and blow into the exaust manifold, i can hear air excaping somewhere around the head or block. i know a little bit can exscape through the starter crank bushing, but it sounds like more than that.
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Old 12-14-2002, 10:54 AM   #5
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i DO have a head gasket.. it just looked like i didnt. i am pretty worried that my problem is the piston and sleeve warped from overheating. there are not scratch marks from dirt on either, but when i take off the exaust manifold and turn the flywheel the piston goes up and starts to compress but air squeezes out from in between the piston and cylinder walls. not a whole lot, but it definetly doesnt hold air for long. did i overheat my engine to the point that it deforms the parts? or is this amount of air normal to squeeze out? please help.. i am so frustrated. i thought i took good care of this thing so far!
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Old 12-14-2002, 01:47 PM   #6
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Default What to look for

Wahturi;

Pull the cylinder head off again and look for the signs of a wornout piston and sleeve.

1) The piston should still be snug when all the way at TDC.

2) Look for scratches on the Piston and Sleeve on the Exhaust port side.

3) Look for the Nickle plating being worn off around the Exhaust port in the Sleeve. You will see the Bronze showing through if it is.

The .15FE is a good motor with just a little work. (Carb, and a Good Pipe) HPI sells a ABC piston, sleeve and carb kit for a reasonable price. Check the HPI website for details. It's in the "Buy HPI" pages.
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Old 12-14-2002, 02:30 PM   #7
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well, everything looks to be in perfect shape. does a worn piton and sleeve usually cause the engine to have a jumpy idle and only make power if leaned out?
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Old 12-15-2002, 06:57 PM   #8
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Check to see if you have a compression problem which it sounds like you do. You don't need to take anything apart just pull on your starter cord and it should be a jerky pull. if it pulls smoothly you don't have enough compression. If you do not have a pull start engine see if you can turn the flywheel with your thumb. If you can turn the engine with your thumb past TDC or starter cord pulls smoothly you will need new sleeve and piston rings. Also if you car is hard to idle when it gets to racing temperature. This is not uncommon. I have used both HPI, OS and Novarossi engines and these parts need replacing every 4 gallons of fuel (16% nitro)or so depanding on how hard I race. Don't forget to change you glow plug often also. The glow plug is one of the problems I have found that most racers overlook if their car is hard to start or idle.
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Old 12-15-2002, 11:06 PM   #9
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Default ONLY 4 Gallons!!

Speedo;

I get more than 6 gallons out of an HPI .15FE. My Picco's 9-10 gallons easily. That's running an average temp of 260-270F. My Picco .15RR, Rear Exhaust will be "2" years old at the end of next month and still makes great power. I would like to replace it with something even MORE powerful, but I can't see retiring a perfectly good engine yet.

All of this was running Trinity Monster HP 30% (20% for the HPI) with 12% oil (power blend). I religiously drain my fuel tanks and put after run oil in my engines after every race.
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Old 12-16-2002, 04:25 PM   #10
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thanks guys. i just found something out. the lip on my exaust pipe broke into a few pieces from an impact and ended up in the second chamber of my pipe. there is a good chance that those pieces could of obstructed both the main and the smaller openings in the pipe. i took them out and epoxied it back together. i guess ill see if that was the problem tomarrow. i hope so, as ive only had about 3\4 of a gallon through this engine and also i broke it in. there is one thing that i wondered, being new and all.. how long is a glow plug normally good for? ive had the same one in since i got it. how can i tell if its beat?
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Old 12-16-2002, 06:10 PM   #11
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Here in Thailand the air temperature can each 40+ C. on race day and the track surface much hotter. Real tough on engines when running a 45 minute race. We run 16% nitro for our races but some guys use 25% nitro when they practice. Most of us run our cars every evening from around 7 to 10 PM at our track. We have races every 6 weeks which is all day and very HOT.

About the glow plug change it after break in. As soon as I have just a hint of trouble starting or idle I change the glow plug. I also change the plug the day of the race. I use the new plug for qualifing and racing then change it again. The guys that don't pay the price during the race.
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Old 12-16-2002, 09:22 PM   #12
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could a bad plug cause the engine to run like crap though? im sure having a new one cant hurt, but for someone like me, who doesnt race yet, can i get away with changing less often? or should i keep right up with it? sorry to keep asking the questions, i am new and you guys have tons of info. its appretiated.
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Old 12-17-2002, 05:23 PM   #13
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You should always keep a spare glow plug in your tool box. You never know when you will need it. One of thre first things I do when my engine is not running perfect when it was before is change the plug. It is much easier than changing all the carburetor settings and it still doesn't run right.
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Old 12-18-2002, 07:51 AM   #14
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Quote:
Originally posted by speedoo
You should always keep a spare glow plug in your tool box. You never know when you will need it. One of thre first things I do when my engine is not running perfect when it was before is change the plug. It is much easier than changing all the carburetor settings and it still doesn't run right.
Check the glowplug with other glowplug starter, it might be the battery in the starter itself. If it's bad, keep it. Use it to throw at those 1/8 guys who mercilessly hit your car.
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Old 12-18-2002, 08:59 AM   #15
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Quote:
Originally posted by speedoo
You should always keep a spare glow plug in your tool box. You never know when you will need it. One of thre first things I do when my engine is not running perfect when it was before is change the plug. It is much easier than changing all the carburetor settings and it still doesn't run right.
i have experienced a bad glow plug during practice...the engine runs fine within the infield, but when i gave it full gas at the begining of the str8, the engine just 'Cut-Off' for 0.5 second then runs normal... when i first noticed the sudden 'Cut-Off', i thought it was running out of fuel...and this 'Cut-off' kept coming back at the same spot where i gave it full gas...then it lasted for a few more rounds b4 the engine flamed out...
Had it changed, everything back to normal...
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