backfire on a 12A?
#4
Let me go over what I did before this, that might help. A few weeks ago I ran some seafoam thru the carb to clean it up a bit. It smoked out my whole street, pissed off my neighbors and so forth. Its kinda been on and off since then since I'm still fighting with this beehive cooler since the oil is still trickling out (the banjo sealing washer is all I need now). The power is definately there though. I have a retired mechanic saying that maybe one of the butterflys is stuck, but he's not sure and hasn't even seen it yet. Hope this sheds some light.
Trending Topics
#8
I need a new user title
Join Date: Oct 2005
Location: Yaizu, Japan
Posts: 2,646
Likes: 0
Received 0 Likes
on
0 Posts
What conditions cause the backfiring? If it's during hard acceleration, it's probably leading ignition. My money is on the leading J109 being on its way out.
#20
ALLROTOR
iTrader: (2)
That's what I was going to say drivin... The stock intake has a shutter valve. Not sure which way it actually works, but I do know it prevents backfiring during deceleration on a stock set-up. Anyways, I'd look into that too. I think I have a pic of it.... It's the brass disc top left barrel. I believe it's controlled by vacuum, maybe check the hose that goes to it to see if it's cracked or if the mechanism is in moving order.
#21
If it happens to be that AAV then is that harmful to the engine? I'm worried about the engine and components here, if its not killing anything then I'm not gonna worry about it, but if its something like detonation that could cause my apex seals to break then I'm worried.
I've read my FSM manuals and searched for J109 and igniter and only came up with 1 write up that explained how to test and overhaul them. What I'm looking for is more of if it is bad am I going to need to redo the timing or something along those lines.
I've read my FSM manuals and searched for J109 and igniter and only came up with 1 write up that explained how to test and overhaul them. What I'm looking for is more of if it is bad am I going to need to redo the timing or something along those lines.
#22
1st-Class Engine Janitor
iTrader: (15)
An afterburn (what most people call a backfire) isn't much risk to the engine. It can be hard on your exhaust system if it gets bad, though. People have blown their mufflers to bits from time to time.
It's basically caused by unburned fuel (from a misfire or a mix error) getting into the exhaust and then igniting.
It's basically caused by unburned fuel (from a misfire or a mix error) getting into the exhaust and then igniting.
#23
Allow me to rephrase this. I know the choke isn't stuck. It used to idle really nice at 700. However it idles like crap now at 500 and chokes up to 2k. While the choke is engaged there is alot of jerking coming from the engine like its pissed off. Sorry about my failed realization of this earlier. I just fixed the oil leak yesterday afternoon and with that off my mind and driving it around I was focusing more on the revs and engine activity as opposed to oil pressure since it wasn't pissing oil anymore.
#25
Thanks for all the help everyone. I happened to figure it out this past afternoon. It was the "air flow" screw on the side of the carb, I'd forgotten that my uncle was screwing with it back when I was doing my seafoam cleaning. It still backfires a little but I'll work it out with a little tuning tomorrow. At least it calmed the engine down.