Javascript Disabled Detected

You currently have javascript disabled. Several functions may not work. Please re-enable javascript to access full functionality.

Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!

Say hello and join the conversation
Subscribe to topics and forums to get automatic updates
Get your own profile and make new friends
Classifieds with all sorts of Subaru goodies
Photo hosting in our gallery
Meet other cool people with cool cars

Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18^th, 1998!

Guest Message by DevFuse

Noob carb questions for EA81

Started by CornerHard , Sep 28 2006 01:19 AM

Please log in to reply

2 replies to this topic

#1 CornerHard

USMB Regular

Members
75 posts

Seattle

Posted 28 September 2006 - 01:19 AM

I read up a bit on carbs today and took the air filter cover off my EA81 to play around and see what was inside. Searching on here for more info didn't turn up too much about the stock Hitachi carb other than it being complicated. So, looking down the top of the carb, there are two barrels. Only the bottom one has a choke, and the top one's throttle body only opens just barely at WOT. I tried propping the choke open and starting the car to see what would happen, and there was a spray of fuel out the throttle body and a lot of noise :confused:

I let the throttle body close, and for the first time ever, my EA81 went into fast idle mode :clap:

After letting the car warm up fully, the choke opened by itself. I played around with the throttle, and the fuel going into the bottom barrel was readily visible, but the top barrel would still only slightly crack open at WOT, with no noticable fuel going in.

Questions:

1) Why does my top throttle body (the one with no choke) only barely open at WOT? How much is it supposed to open? It seems like I'm losing a lot of potential performance here if I'm only using half the air intake.

2) What could be stopping my car from going into fast idle mode? Why did it go into fast idle after starting the car with the choke manually propped open?

Back to top

#2 beataru

Subarus Catch on fire?!

Members
1,202 posts

Phoenix

Posted 28 September 2006 - 02:39 AM

well for number 1... it could be your secondary sticking... we had to replace the carb on the 86 GL.. afterwards it worked perfect.... (hehe i think its so funny that it has 1) hey what did the noise sound like.. you mean like screeching or engine noises or just sucking wind???

Back to top

#3 GeneralDisorder

Elite Master of the Subaru

Members
20,279 posts

Portland

Posted 28 September 2006 - 02:53 AM

Fast idle on the Hitachi is very tricky to get right. It's all about adjusting the choke settings, and cleaning the linkage. Basically you have to tear it down.

Secondary is vacuum operated from inside the carb casting. It will only open under load usually. WOT will not open it unless conditions dictate (in gear, up a hill in third for example).

GD