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Old 11-09-2014, 10:25 AM   #1
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Unhappy New Engine wont start

Hi everyone...

I am new here... and somehow new to Nitro engines... but ive got enough info about how such engines run...

I bought a cheap chinese model called HSP which is very popular around where i live... i thought i would try these things first... car was perfectly fine... and suddenly car wouldnt start... not gonna say much into what happened after and how i kept trying to make it start... it was an SH engine .21 so i made up my kind and got a new LRP Z.28 R engine along with a new flywheel... cluth... bell... etc...

The engine did fit right... now today was my first day to start the engine... it was supposed to be a FRESH start... new engine!!

I pulled the pullstart and it started and went off in 10 seconds... long story short... kept trying and found out the following... If i blow into the exhaust gas line... it runs for 10 seconds and then goes off... so this made me believe that the pressure from the tank is ok... it seal right... i even pressed it with my finger and started the engine... still goes off...

the exhaust seems fine... i dunno what else to do... i really was excited to start my new engine but it didnt work out

The only thing i noticed is that the carb can be removed if i put a lil pressure... i read somewhere that this LRP engine is deisgned this way... the carb is always loose!! I am really confused... i am capable of checking any specifc part... but old engine might have been unable to start due to same problem... or lets forget about the old one... this is a new engine... why isnt petrol getting in after it starts?? engine seems okay coz if i blow gas into it... it starts for a few seconds then goes off... so definetly there is a leak somehwere... but where can that be? :S

EDIT:

I would like to add... when i blow into the exhaust gas line... i see fuel getting to carb... along with alot of air bubbles... is that normal? maybe coz am blowing hard? or is it a sign of something?
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Old 11-09-2014, 10:41 AM   #2
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Sounds like it's not priming before starting or glow plug is out or weak. Do this

Make sure you're glow plug ignitor is charged and the glow plug glows bright orange. Not dull red or a very slight orange. Check the glow plug by removing and lightly pushing into the stem of the ignitor. If it glows bright orange, reinstall. Careful it will get hot fast.
Hold you're finger tip over the exhuast outlet while you give it a medium speed pull on the starter rope. Watch the fuel line from the tank to the carb. You're looking for any sign of fuel traveling to the carb during pulling the starter rope. What you're doing by holding you're finger over the exhuast outlet is pushing the exhuast back into the tank. Which pressurizes it, and forces fuel out of the tank, towards the carb fuel inlet.

Only pull the starter rope maybe two-three times, then let you're finger go off the exhuast outlet. Now put the ignitor on the glow plug and crank the engine. See what happens and let everyone know.

DO NOT get any of this fuel in you're mouth by blowing on lines etc. I have been sick before from inhaling fumes and eating some, tears you're stomach up.
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Old 11-09-2014, 10:51 AM   #3
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You blow the pressure line, Fuel goes to carb. When it stalls line to the carb has air? Count how many turns the HSN to close, make note. If 3.5-4 turns to close. set it to 3 turns. Prime to carb and restart. Idle maybe high, lower idle speed. Then continue tuning engine. Another thing to see Seal fuel line from tank to carb, to prevent air bubbles forming. Small air bubbles like fish eggs is just carb adjustment( tuning).
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Old 11-09-2014, 11:24 AM   #4
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thnx for the replies... the glow plug is okay... its a new engine with a new plug... plus i tested it... and the igniter is new as well... lol and lights up very well... egine starts for 10 seconds... so its a sign its ok... when it goes off... blowing into the exhaust line gets it up again for 10 more seconds... now filling up the tank to the MAX got it running for 30 seconds...

as for the the second comment... yes... i can see air all the time in the gas line... mainly when am blowing into the exhaust gas line... there would be alot of air and gas going to carb... but it fills up.. thats why is starts... once its on... it lasts 10 seconds only

is the loose carb the reason? I will try playing around with the with HSN and idle screws... but I thought the LSN is the one that affects the start of the engine!!

anyways... i doubt this is the reason but its worth a try... i think its another issue... but i dunno what that might be!!
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Old 11-09-2014, 12:54 PM   #5
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Just set the idle a bit higher and do pre-heat the engine.
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Old 11-09-2014, 01:54 PM   #6
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I would suspect your tank lid seal isn't sealing good enough. also, I would highly recommend some engine sealant. such as lucky7.
use it on everything even the screws to the carb. the engine will hold a tune very very well with it all sealed up with sealant.

I've also seen the screw for the carb too long not allowing it to pull the cam and snug down on the carb. a lot of guys crank on it some more but they don't realize it's tight because it's bottomed out not because it's pulling on the carb.
a washer or two for the screw should be enough to allow it to work as intended.

don't try tuning a engine until you get it broken in. just worry about making it run for now. leave it slightly rich
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Old 11-09-2014, 04:44 PM   #7
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Quote:
Originally Posted by spookie View Post
Sounds like it's not priming before starting or glow plug is out or weak. Do this

Make sure you're glow plug ignitor is charged and the glow plug glows bright orange. Not dull red or a very slight orange. Check the glow plug by removing and lightly pushing into the stem of the ignitor. If it glows bright orange, reinstall. Careful it will get hot fast.
Hold you're finger tip over the exhuast outlet while you give it a medium speed pull on the starter rope. Watch the fuel line from the tank to the carb. You're looking for any sign of fuel traveling to the carb during pulling the starter rope. What you're doing by holding you're finger over the exhuast outlet is pushing the exhuast back into the tank. Which pressurizes it, and forces fuel out of the tank, towards the carb fuel inlet.

Only pull the starter rope maybe two-three times, then let you're finger go off the exhuast outlet. Now put the ignitor on the glow plug and crank the engine. See what happens and let everyone know.

DO NOT get any of this fuel in you're mouth by blowing on lines etc. I have been sick before from inhaling fumes and eating some, tears you're stomach up.
+1

Even the very worst old nitro engine will start cold, it might not run after 2 minutes but it will start from cold. Work from there, read the sticky in the NItro Engine tuning thread and slow things down and fix that loose carby

h
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Old 11-10-2014, 06:02 PM   #8
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Quote:
Originally Posted by mtpocketsracing View Post
I would suspect your tank lid seal isn't sealing good enough. also, I would highly recommend some engine sealant. such as lucky7.
use it on everything even the screws to the carb. the engine will hold a tune very very well with it all sealed up with sealant.

I've also seen the screw for the carb too long not allowing it to pull the cam and snug down on the carb. a lot of guys crank on it some more but they don't realize it's tight because it's bottomed out not because it's pulling on the carb.
a washer or two for the screw should be enough to allow it to work as intended.

don't try tuning a engine until you get it broken in. just worry about making it run for now. leave it slightly rich

Thanks for all the advise given guys... I am still unable to know what could be wrong... the engine to header seal is new with the engine.. i changed the fuel tank... the new tank is the exact same story again!! maybe runs for 15 seconds instead of 10 seconds!! Now on a full tank... it started just fine... and this time it was different... it started up for a whole minute... the first 30 seconds were all smooth and i was happy maybe the new tank fixed it... but fuel was being thrown out of the exhaust like crazy... but i ignored it hoping it would stay on...

Suddenly the engine started revving up... and it kept going like that for like the remaining 30 seconds and i tried to reduce the idle... but fumes were coming out of the carb!! the engine and carb got REALLLLYYY HOT... it then went off... and i didnt dare to start it again!! the engine is new and i think what happened was a big mistake... its all coz of the air going into carb making it VERY lean... i hope i didnt ruin the engine... coz this is FAR from a proper break-in!!

please advice... i checked all seals again... header to muffler is okay... new fuel tank... new engine!! what can be wrong?? am really confused!!

Can it be the exhaust?? is it possible that since my exhaust was on my .21 SH Engine... maybe i need an exhaust which can push more air into the fuel tank?? I mean i dunno such stuff... but i cant think of anything else!!

I checked all needles... they werent far from the suggested stock settings either... which is basically more on the rich side... air bubbles make it lean anyways... so the car goes crazy revving really high...

Any advice would be much appreciated...
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Old 11-10-2014, 11:13 PM   #9
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I have to ask?

HSN, how many turns to closing?

What is the air gap of throttle(idle speed) by mm's?

Before and when it stalls, Fuel line tank to carb shows full or air??

When it starts an run, throttle up does it stall, and air in the fuel line?

How high the idle speed??

Does it blow smoke?


Slide carb or rotary?

Answer these question will give us a idea what's happening.
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Old 11-11-2014, 12:02 AM   #10
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Quote:
Originally Posted by Geezatec View Post
I have to ask?

HSN, how many turns to closing?

What is the air gap of throttle(idle speed) by mm's?

Before and when it stalls, Fuel line tank to carb shows full or air??

When it starts an run, throttle up does it stall, and air in the fuel line?

How high the idle speed??

Does it blow smoke?


Slide carb or rotary?

Answer these question will give us a idea what's happening.

HSN and LSN were 3 turns to close... i closed them anyways and made them 3.75 as per manual... as for idle needle... it was stock... but i increased it... then decreased it again to see if any difference... sill the same... cant tell u measurement coz its inside and i cant measure it

as for the air in fuel line... this happens even on full tank... but it works fine for like a few seconds after priming and starting the engine... after that... u start to see the air bubbles... and the engine starts revving... and then goes off... so yes... there is smoke when it starts... but when air starts coming in... there wont be smoke anymore...

Tried to keep throttle on hoping it wont stall but that didnt help at all... having a little throttle... half throttle or even full throttle did not give any boost at all... with or without throttle it will still go off in a few seconds...

as for the last question... i really dunno what carb type this is... cant tell the difference... its the LRP z28 R model and is new so whatever that carb has is what Ive got i guess...
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Old 11-11-2014, 07:50 AM   #11
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Through manual, those adjustments let you start up the engine, it still has to be tuned. After it start. turn on TX & Rx, give it throttle. Does it stall? If it does, HSN 1/8th turn CW. Give it throttle, Do this 1/8th turn of HSN till it stays running. Idle may rise, turn it down to your comfortable, Not as low as a Harley. That the first step. Ask for second step until first step is done. Be patient!!! Bubbles in fuel line will dissipate when its tuned correctly. HSN could be adjusted to 2 turns from closed. One step at a time so you'll understand. Another thing , Do you have a temp Gauge??
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Old 11-11-2014, 08:03 AM   #12
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Example of Carbs, Rotary and Slide. First photo is Rotary.
Attached Thumbnails
New Engine wont start-osmg3817-rotary-carb.jpg   New Engine wont start-osmg3818-slide-carb.jpg  
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Old 11-11-2014, 10:38 AM   #13
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Just another tip, have you put on new fuel line . It sounds like you may have an air leak somewhere. Check the screws on the engine head to be sure it's tight. An air leak will make it do just what you're saying it's doing.
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Old 11-11-2014, 01:22 PM   #14
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Quote:
Originally Posted by spooky 1 View Post
Just another tip, have you put on new fuel line . It sounds like you may have an air leak somewhere. Check the screws on the engine head to be sure it's tight. An air leak will make it do just what you're saying it's doing.
My first post, told him to seal fuel line from tank to carb. Should tell him also line from tank to carb the shortest as possible.
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Old 11-11-2014, 09:01 PM   #15
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Sounds to me like the low speed is too lean and or theres debris in the main needle inlet possibly
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