R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro Off-Road

Reply
 
Thread Tools Search this Thread
Old 08-20-2009, 07:19 PM   #1
Tech Adept
 
sokar's Avatar
 
Join Date: May 2009
Posts: 160
Default Engine acting funny.

After tearing down my engine and discovering it lost some compression, I put it back together and started it up. If I leave the igniter in, it runs OK. When I take it out, the engine bogs, warbles, pops, gargles, spits, smokes, etc. but only when accelerating and deccelerating. I've been trying to tune it but haven't had much luck. I replaced the glow plug not too long ago (about maybe 1/4 of a gallon run through the current glow plug). What could be causing this, and how could I fix it?
__________________
Team Terribles

God Hates Faqs (frequently asked questions)
sokar is offline   Reply With Quote
Old 08-20-2009, 07:23 PM   #2
Tech Fanatic
 
mudboger07's Avatar
 
Join Date: Dec 2008
Posts: 939
Default

Have ya check to se if you put the piston in backwards? It is possbile, and wil run but not very good...
__________________
Proud Sponsor of a 10 year old.....
losi 8ightB 2.0/DX3S/VSpec* Revo-3.3*mod slash*blade-mcx*axial GC2
Team Nitro** F-14*Team Terribles/Answer-RC

Ken
mudboger07 is offline   Reply With Quote
Old 08-20-2009, 07:26 PM   #3
Tech Adept
 
sokar's Avatar
 
Join Date: May 2009
Posts: 160
Default

Quote:
Originally Posted by mudboger07 View Post
Have ya check to se if you put the piston in backwards? It is possbile, and wil run but not very good...
I took everything except the piston and sleeve out. I left those alone.
__________________
Team Terribles

God Hates Faqs (frequently asked questions)
sokar is offline   Reply With Quote
Old 08-20-2009, 07:26 PM   #4
Tech Regular
 
coviello's Avatar
 
Join Date: May 2009
Location: goshen ny
Posts: 357
Trader Rating: 6 (100%+)
Default

new shims and seal that bad boy up.
coviello is offline   Reply With Quote
Old 08-20-2009, 07:40 PM   #5
Tech Fanatic
 
mudboger07's Avatar
 
Join Date: Dec 2008
Posts: 939
Default

Like covielle said seal the back plate and card with silicon and id install a new plug then prob recheck your tune.......
__________________
Proud Sponsor of a 10 year old.....
losi 8ightB 2.0/DX3S/VSpec* Revo-3.3*mod slash*blade-mcx*axial GC2
Team Nitro** F-14*Team Terribles/Answer-RC

Ken
mudboger07 is offline   Reply With Quote
Old 08-20-2009, 07:46 PM   #6
Tech Adept
 
sokar's Avatar
 
Join Date: May 2009
Posts: 160
Default

Oh, it also smokes like crazy. There's tons of blue smoke coming from all around the engine
__________________
Team Terribles

God Hates Faqs (frequently asked questions)
sokar is offline   Reply With Quote
Old 08-20-2009, 07:53 PM   #7
Tech Elite
 
HaulinBass's Avatar
 
Join Date: Dec 2004
Location: valleyview alberta canada
Posts: 2,114
Trader Rating: 8 (100%+)
Default

replace the plug if that doesnt help lean the engine out, no engine will run rich with an airleak its physiclly impossible.
HaulinBass is offline   Reply With Quote
Old 08-20-2009, 07:53 PM   #8
Tech Fanatic
 
mudboger07's Avatar
 
Join Date: Dec 2008
Posts: 939
Default

again after sealing the motor, you might want to check the ext gaskets, it could also be the bearings......
__________________
Proud Sponsor of a 10 year old.....
losi 8ightB 2.0/DX3S/VSpec* Revo-3.3*mod slash*blade-mcx*axial GC2
Team Nitro** F-14*Team Terribles/Answer-RC

Ken
mudboger07 is offline   Reply With Quote
Old 08-20-2009, 08:06 PM   #9
Tech Adept
 
sokar's Avatar
 
Join Date: May 2009
Posts: 160
Default

Quote:
Originally Posted by mudboger07 View Post
again after sealing the motor, you might want to check the ext gaskets, it could also be the bearings......
BTW I bent a shim but I didn't think it mattered because it is being squished by the cylander.
__________________
Team Terribles

God Hates Faqs (frequently asked questions)
sokar is offline   Reply With Quote
Old 08-21-2009, 06:32 AM   #10
Tech Elite
 
Zerodefect's Avatar
 
Join Date: Apr 2008
Location: Underground, Ohio
Posts: 4,305
Default

Quote:
Originally Posted by sokar View Post
BTW I bent a shim but I didn't think it mattered because it is being squished by the cylander.
It matters, if it it was bent enough, then the head might not be able to squish it flat. metal stretches when its bent. When you straighten it, it deosn't go back to where it was very well, especially a ring or round piece.
Zerodefect is offline   Reply With Quote
Old 09-03-2009, 09:47 AM   #11
Tech Rookie
 
Join Date: Dec 2007
Posts: 13
Default

Quote:
Originally Posted by HaulinBass View Post
replace the plug if that doesnt help lean the engine out, no engine will run rich with an airleak its physiclly impossible.
This doesn't make sense to me. If an engine isn't getting as much air as it should, wouldn't there be more fuel than needed, therefore it's rich ? Or do you mean "rich" as in the amount of fuel it'd need if the air was right ?
Jeimuzu is offline   Reply With Quote
Old 09-04-2009, 11:06 AM   #12
Tech Elite
 
HaulinBass's Avatar
 
Join Date: Dec 2004
Location: valleyview alberta canada
Posts: 2,114
Trader Rating: 8 (100%+)
Default

an engine that is sucking air from somewhere else other than the carb, cannot run rich. the fuel and air go through the carb at a certain mix if there is air entering the engine anywhere else than more air is getting added to that mix and its being carborated again.
Think about it like sucking a pool of water up with a water pump if you put a huge hole in the suction hose its going to suck a bunch of air instead of water.
HaulinBass is offline   Reply With Quote
Old 09-04-2009, 12:43 PM   #13
Tech Rookie
 
Join Date: Dec 2007
Posts: 13
Default

Oh I was thinking that an airleak let air out, not extra air being sucked in.
Jeimuzu is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Houstons Engine Service H.E.S. houston Offroad Nitro Engine Forum 8821 06-17-2017 12:29 PM
R/C Stuff Selling Kenneth Tan Singapore R/C Racers 45728 09-09-2009 07:19 AM
Who can I ship my motor to to get a failure diagnosed? Lonestar Nitro Off-Road 30 07-16-2009 08:12 AM
vspec unbeatable?!?! liteumup387 Nitro Off-Road 36 06-14-2009 06:13 AM
What does it do when you pinch an engine???? Help halfman Nitro Off-Road 14 03-21-2009 07:38 AM
I need advice...PLEASE HELP!!! luketob Nitro On-Road 10 08-15-2003 01:40 AM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 12:45 PM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net