Why doesn't my 2.5 start up without this 'tube' in place

[SummerSoFar]

Yo dudes!

I picked up a new K&N filter that fit nicely around the stock air filter housing mounting points. In doing the swap, I also removed a ~3 inch rubber tube that connected from a port hole on the engine to the filter housing...

With the new K&N in place, I was unable to get the 2.5 engine started (even after spraying on some starter fluid) :censored: Frustrated, I put the stock filter with 'tube' back on, and then the engine fired back up.

So my question is, what does this little magical rubber tube do, and is there any hope in me still being able to use my new $20 filter?

 

[71dodge]

if that tube is not in place it will not start i froget what it does but leave it in

just put on the motor were oyu found it and turn it down and dont mess with it and you will be fine

 

[milo raptors]

ok dude there is hope that tube goes to the brether on your engin an you should disconect it and run it with stock air box an no tube if it dont run the you just mite be stuck i seen em run with K an Ns befor maby its to lean i duno but usaly them brethers like the negative presure

 

[waynelass]

yes you have to have that hose hooked to a breather ,you can go to an auto parts store and pick up a small one that plugs into the end of the hose ,i just picked one up friday ,it cost me 2.50:wink:

 

[waynelass]

it has somthing to do with the amonut of air getting into the intake valve ,it has to be limited .

 

[125ccCrazy]

Hmmm thats interesting.... I have a 2.8 I test fired setting on the floor, it would run with a prime but wouldn't any throttle or run without the choke.... I was assuming it had to be a lean condition due to no filter or crap in the carb not allowing fuel flow... not sure how the hose not being hooked up would cause that as it's an emissions thing to pull the fumes out of the engine and reburn them sorta like a pcv on a car.. I was looking at making an intake and running a 16mm mikuni on a build for my grandson...

 

[waynelass]

not sure but it has to be vented somewhat,in the old breather ,the hose is somewhat restricted ,,,more air ,more gas, more exhaust ,just the breather alone could cause the problem ,cause it to run really lean

 

[SummerSoFar]

yes you have to have that hose hooked to a breather ,you can go to an auto parts store and pick up a small one that plugs into the end of the hose ,i just picked one up friday ,it cost me 2.50:wink:

Thanks for the info, waynelass.:biggrin:

Forgive my ignorance, but could you point me to an example of a breather, say, on partsamerica.com or autozone.com?

 

[waynelass]

auto zone ,they are the type of breather that sometimes clip inside a real large size breather on a car and usually have a small hose going to it through the breather housing ,they work great and are inexpensive:wink:

 

[waynelass]

i will post a photo so you can see what i have

 

[waynelass]

this is what i have for the vent .

 

[SummerSoFar]

Thanks so much! :xmas-smiley-016:

Off to the parts store I go!

 

[cxbra]

I took the breather tube off of mine (actually, I disconnected it from the intake then it fell off!) and it actually seems to run better. I am actually able to run with the choke fully off (all the way to the left) now, with the tube connected there was no way it would rev with the choke fully off. I didnt notice a gain in performance, so I just run with half choke (like most of us stock engined guys) like normal (no tube still).

I think you should take the hose off or get a breather filter for it, then re-tune your carb. Carb tuning is probably the biggest part in your engine not starting up w/o the tube on.

 

[SummerSoFar]

Update: I just came home from AutoZone with a $2.29 Deutsch BF301 breather filter (same as waynelass'), and my results are sub-par with it -- hard to start and more sputtering while opening up the throttle.

So cxbra, how do I go about tuning the carb? I have recently pulled it off to make sure it was clean, which it was...

The crazy thing is, with the original filter back on, it starts right up.

 

[waynelass]

go to the affordable gokarts web site they have an page on carbrator tunning and drilling gas jets ,its very good ,step by step instruction wwwaffordablegokarts.com :wink:

 

[waynelass]

running to lean ,it is getting lots of air and not enough gas