Loss of high end.

[rpg711]

My new force 21 is on it's 4th break in tank, where it should be running full throttle for 3 seconds(traxxas method)
The thing is, i CANT get it up there.
Symptoms-
Oil all under the motor
Oil all over the glow plug
Inability to reach top rpm/speed
Loss of power

I have tried:
Changing glow plug
Leaning mixture a bit(1/8 turn)

Dunno what happened, I never went over half throttle for first 3 tanks so I didn't know there was this problem.
What is wrong? It has a crap load of pinch and compression still.

[vnmsgt]

What is your temp. It still might be too rich. 1/8 turn from stock might still be way too rich. As for the oil and stuff, make sure you have a gasket on the glow plug and also make sure the exhaust gaskets are not leaking.

[rpg711]

What is your temp. It still might be too rich. 1/8 turn from stock might still be way too rich. As for the oil and stuff, make sure you have a gasket on the glow plug and also make sure the exhaust gaskets are not leaking.
I have no idea of the temps, but it is hot to touch(i can't leave hand on for more than 3 secs) but it isn't scalding(over boiling, 230+)
so i'd say its around 200-210F...
What do I do? It also sounds really scary... it seems to be having trouble accelerating... and it cuts out frequently(flooded with fuel)
Confirming this is a HSN problem?
It seemed to me as it is too rich since it cut out from flooding, and obviously was choking for air.
There is oil all on the chassis, and also under the chassis.

[rpg711]

All I need is a yes or no answer, plz answer so I'll know if I can lean or not.

[bc24fl]

rpg i experienced similar problems. It's going to be hard to help you without an exact temp reading. As far as the leakage mine was due to the idle screw.

Also, don't put too much value in Caster stock settings. Get the manual on the net and set it according to that.

[rpg711]

rpg i experienced similar problems. It's going to be hard to help you without an exact temp reading. As far as the leakage mine was due to the idle screw.

Also, don't put too much value in Caster stock settings. Get the manual on the net and set it according to that.
I will have an exact temp reading tomorrow, when I go out to buy an infrared temperature sensor

[vnmsgt]

I would try leaning it out a half turn more and see what happens. It will probably run much better. If you can hold you hand on the motor for 3 seconds it is not too hot and therefore running very rich. You probably have alot of smoke coming out of your exhaust too.

[rpg711]

I just leaned it by 1/2 turn, it still was the same... Also, I would like to note that the LSN is WAAAY screwed in, not flush like it was supposed to be.
BUT, the engine still takes a good 8 seconds to rev up and die(mabee because of long fuel line)
God, I just want to finish breaking this thing in, or I'll have so much spoiled fuel.(250cc, alot since I only bought a quart)

[vnmsgt]

I just leaned it by 1/2 turn, it still was the same... Also, I would like to note that the LSN is WAAAY screwed in, not flush like it was supposed to be.
BUT, the engine still takes a good 8 seconds to rev up and die(mabee because of long fuel line)
God, I just want to finish breaking this thing in, or I'll have so much spoiled fuel.(250cc, alot since I only bought a quart)
Turn in the HSN needle in and see how many turns in before it stops. Then post back. You might have it too lean then but it should be alot hotter than. If you had a temp gun it would make it WAAAAY easier to find out what you have your motor set at. Typically HSN needles are over 3.5 turns out from bottom. Also best thing to do about you oil you have leaking is to clean it all off and run the car on a stand or something and watch for wear it leaks at and you will know what it going on.

[rpg711]

My HSN needle is 3.5 turns out exactly... it used to be 4 turns out.
What could be the problem?
I simple exhaust gasket leak wouldn't cause a loss of the other half of the RPM spectrum completely right? It would just take more time to get to full rev right?
Could I call you or is now not a good time?

[vnmsgt]

Well guys I have spoken to rpg711 on the phone and from what has been said here I think his glow plug may be bad and not burning all the fuel and is why he has not top end. HSN seems ok and he said he can hold his finger on the head for a couple secs so you know it is not probably over 150 degrees. I told him to try another glow plug and see how it goes. Anybody got any other ideas to help him get his buggy up and kicking butt!

[rpg711]

Yes, we have come to the conclusion that it has to be my glow plug.
I would like to know, could I wash glow plugs? 2 of my 4 plugs have oil ALL OVER them. It probably is causing bad connection, thus causing low heat and improper burning of the fuel, resulting in inability to burn more than 1/2 throttle worth of fuel.
If it works out tomorrow, good.
If not, then expect another phone call :P though then there would really be no alternative problem short of bad throttle servo and venturi not opening up(both checked by taking air filter off)

[hakmazter]

Plan on going through a few glow plugs during break in. Just remember they are getting saturated at first...It is hard on them and they usually fail or give out.

Mike

[bc24fl]

Yes, we have come to the conclusion that it has to be my glow plug.
I would like to know, could I wash glow plugs? 2 of my 4 plugs have oil ALL OVER them. It probably is causing bad connection, thus causing low heat and improper burning of the fuel, resulting in inability to burn more than 1/2 throttle worth of fuel.
If it works out tomorrow, good.
If not, then expect another phone call :P though then there would really be no alternative problem short of bad throttle servo and venturi not opening up(both checked by taking air filter off)

I've washed my plugs in the past and they work fine. After they dry I usually lube them up with wd40.

rpg, temp sensor is worth every penny. I can recall MANY TIMES being at 290-300 degrees and having to adjust settings.

GL!

[razzor]

Use a 5 or 6 heat range plug.
try and tune the engine on the bench gradually adjusting the hsn leaner till the motor cleans out.
note also if the bottom response is good and as you go over half throttle the motor labours up that would be a sign you lean on teh bottom and rich on the top.

I have never needed to really look for the tune on the Force motor.
Usually i richen hsn by 1 turn and then run the motor at 1/2 throttle for about 3/4 tanks but after letting it idle through 2 tanks.

Note that as you are rich you might not get much smoke but as you get closer to the sweet spot the motor will start smoking more.
Dont have a run in tuned engine with me so i cant reference the needle settings but i do know that the HSN is around the 3 - 3.5 turn mark and lsn should be around +- 2 turns

Dont worry about making teh engine too rich it just wastes fuel and stresses teh rod.
Heat cycle the motor is more important so get it up to temp +- 200-220 and run a tank.
i dont use a temp gauge but just put a bit of spit or water on the head and it should take 3-5 seconds to evaporate.
if you do get a temp gauge make sure its a good one.
Ive used teh Duratrax ones but they are very inconsistent.
Exergen are the best but $$$. The Odonnel looks good though but again the temp is a reference and you must tune for performance.

[vnmsgt]

Ive used teh Duratrax ones but they are very inconsistent.


Inconsistent??? I never thought 25 degree differences between mine and other peoples with the same temp gun as inconsistent!! LOL! You are right though. Everyone of those is different. I have on too.

[rpg711]

Use a 5 or 6 heat range plug.
try and tune the engine on the bench gradually adjusting the hsn leaner till the motor cleans out.
note also if the bottom response is good and as you go over half throttle the motor labours up that would be a sign you lean on teh bottom and rich on the top.

I have never needed to really look for the tune on the Force motor.
Usually i richen hsn by 1 turn and then run the motor at 1/2 throttle for about 3/4 tanks but after letting it idle through 2 tanks.

Note that as you are rich you might not get much smoke but as you get closer to the sweet spot the motor will start smoking more.
Dont have a run in tuned engine with me so i cant reference the needle settings but i do know that the HSN is around the 3 - 3.5 turn mark and lsn should be around +- 2 turns

Dont worry about making teh engine too rich it just wastes fuel and stresses teh rod.
Heat cycle the motor is more important so get it up to temp +- 200-220 and run a tank.
i dont use a temp gauge but just put a bit of spit or water on the head and it should take 3-5 seconds to evaporate.
if you do get a temp gauge make sure its a good one.
Ive used teh Duratrax ones but they are very inconsistent.
Exergen are the best but $$$. The Odonnel looks good though but again the temp is a reference and you must tune for performance.
My motor used to be at 4 turns out hsn, I didnt fool with the LSN cause that really doesnt matter(precision tuning doesnt matter when I have a large problem) and with my talk with vnmsgt I leaned it by .5 turns. Now its at 3.5 turns out.
Inconsistency is fine with me, I'll just take temps many times and avg them to get a consistent temp.
Going to go out and try new glowplug now, hope it works!

[rpg711]

Ok, it WAS the glow plug!
I changed it and everything was fine, albeit the throttle response was rather slow and it obviously was running rich. It still revved to almost full rpm(not full-out screaming, but close)
Got my 4th tank in!
5th tank will be fun... full throttle for 5 secs :)
I'm going to be getting that duratrax IR sensor today-tomorrow from my LHS, along with some more glow plugs... lol.
Thanks for all your help!

[vnmsgt]

Glad to hear you got it running. I thought that was what it was!