flooding engine on let off

[out-front-Y]

Well was out today with my new engine installed in my rx1. Sled running
20# of boost everything running great. My problem is after a run and let off it is flooding the engine and i have to play with the throttle to get it cleaned out im running stock spring. I have red springs but im thinking
that it will make it worse because they are lighter and keep slides open longer.This is something that has always been a problem for me no matter what engine or boost .Any help will be great Patrick.

 

[mbarryracing]

Do you have a Blow Off Valve?

 

[out-front-Y]

Yes i have one in charge pipe before intercooler , front mount turbo.

 

[mbarryracing]

Sounds like still having too much pressure to the float bowls after the throttle is chopped closed, forcing excessive fuel out into the carb bores and floading your engine.
How do you have the BOV plumbed for vacuum? Maybe it's not getting a strong enough signal...
Maybe the BOV is not large enough?

 

[out-front-Y]

I have vortex bov hooked up in nipples in carb boots .


I wish this was efi like my trail 1200 skidoo fpp stage one i have no fuel
problems at all. And no carbs to work on.

 

[mbarryracing]

If the BOV is in the charge tube, where are the float bowl vents plumbed? There has to be a reason the bowls are seeing raised pressure until the boost has settled back down.

 

[out-front-Y]

Im get my carb boost from intercooler . i have two nipples on interclooer
one for fuel reg and one for carbs.

 

[mbarryracing]

Are you're AFR's good (not too rich) when on the throttle?
Where are the slides pressurized from? Same place?
My BOV's have always been in the intercooler.
Other then float level or not dumping enough boost... I'm kinda out of guesses. But surely some other members that are more experienced with carbed models will be along to give some advice.
Have you tried calling the producer of your kit?

 

[wienerwater]

I run an Alpine front mount on an '03 rx1 and have the same problem.
I asked about this last year and basically it's a common issue and not much can be done, apparently, as Alpine says.
The main thing with them is to not just let go of the throtttle on high boost runs, like climbing a steep hill. Try and let back if you can instead. It's a pain in the butt, and if anyone knows of a solution, I would like to know as well.
If it does just die, remember to hold it wide open throttle, and start the engine.It takes a bit but it will start if you just pin it and feather it when it starts to fire up.Also, have a good battery, not some lightwieght thing either.

 

[Blue shadow]

same thing here ,on hight boost don t leave the throttle go all at once but just ease in to it and your fine .

 

[rxrider]

How is your floats set? Could be float needles not seating 100% and leak fuel. Some have adjusted floats to min. spec of 15mm. If your fuel pressure regulator get its signal from the IC airbox you may have to install another BOV in that area to dump pressure as fast as possible reducing FPR pressure as early as possible. How is your idle AFRs? Low (fat) idle AFRs will make it worse.
I also do as wienerwater says, I never let off 100 % after a WOT climb, I know this is not possible at all times but when I can I do it like that. My AFRs tells me that AFRs go fat when I shut the throttles closed. Many have had good luck with connecting the FPR at the carb boots, but that is another can of worms....

 

[Mountaintech]

This was a very common problem with the carbed turbos a few years back. I had an MCX rear mount and SOLVED my problem by taking my signal for the fuel pressure regulator from the intake manifolds instead of the intercooler. That way when you chop (close) the throttle the regulator does not sense a boost spike and overfuel. Opinions at the time by some people were that doing this would cause a lean condition at part throttle but this was never a problem with my sled. Put over 10,000 kms on it before selling it, and as far as I know its still going strong.

 

[out-front-Y]

Thank i will give it a try.

thanks for everybodys responce.

 

[out-front-Y]

hooked it up to carb boots and every thing is good now.
thanks for the help

 

[Mountaintech]

hooked it up to carb boots and every thing is good now.
thanks for the help

Glad it worked for you.