Sign in to follow this  
Followers 0

Rotax 582 Bings spitting fuel - carb bowl venting problem?

4 posts in this topic

Posted

For two years, I've had problems with fuel overflowing out of the carb jets when I first pressurize the fuel system, especially if the carb bowls were drained to begin with.   I tried everything I could think of, including:

  • reducing inlet fuel pressure
  • replacing float valves several times
  • adjusting and tinkering with the floats every which way to encourage quick action. 

About half of the time, fuel would continue to freely flow out the jets and the carb float valves wouldn't seat until I shut down the pump and let things settle for a couple seconds, then tried again.    Obviously not acceptable :)

 

I finally noticed that it didn't happen when the carb vent tubing was removed.  I experimented, and sure enough, could reproduce it 100% of the time with the prescribed "pinhole in a tube" carb vent, and could never reproduce it if the vent port was unrestricted.  I ended up using unrestricted 1/8" line into a small breather air filter as a vent, and things have worked great.

 

However, now I want to add a hacman-style mixture adjustment, which by its nature requires a vent port that's restrictive enough so that you can draw bit of a vacuum against it to lean out the mix.   I'm scared to tread into this territory without understanding why restricting the vent port earlier caused an engine-disabling problem.  

 

Does anyone have experience with these symptoms?

 

Thanks!

Jim

 

 

 

Share this post


Link to post
Share on other sites

Posted

I can't think of anything that would follow with your issues.  It just does not make sense to me.  What is the difference between a couple holes in the tube versus the open tube?  To put the holes in my tube I heated a pin and melted them in there.  There should be 4 holes.  Top and Bottom and on each side in a cross pattern at the bottom of the tube to drain any liquid that should get in there.  The other thing you can do is look for an Arctic Sparrow Mixture control that someone may be selling.  I love mine.

 

:BC:

Share this post


Link to post
Share on other sites

Posted

I don't know how much pressure the Bing 54 carbs can take before the float needle valve is overpowered, but I know it doesn't take a whole lot on a Bing 64 or 94.  Give the tech guy at Bing carbs a call.  He was very helpful when I had a problem with flooding.  By the way, he ended up being right, even though I kind of  didn't believe it at first.  Wonder how big your float needle jet is, they make 3 different sizes, from 1 to 3 MM for the 64 and 94 carbs.  Largest one is for gravity feed, I imagine they have different sizes for the 54 also.  Bigger jet will take less pressure before it will leak.  Just a few random thoughts that may or may not help... Jim Chuk

Share this post


Link to post
Share on other sites

Posted

I've had a similar issue a couple of times after removing the float bowl and putting it back on. In my case the little pins got caught behind instead of on top of the floats or visa versa. Anyway would run but puke gas. Removing and reinstalling float bowl without gas in the bowl fixed the problem. It was only when I tried to reinstall the float bowl when full of gas that the setup got misaligned and puked gas. probably not your problem, but real easy to remove float bowls, empty the gas out and reinstall them. that will assure that the pins are on the right side of the needle setup.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0