YF problems, continued...

[Bort62]

So, I think I fixed my acc pump problem by removing the ball and weight as well as stacking some washers on the pump plunger to push it down farther.

I've got a healthy squirt now. No more starting problems, either.

So I turned up the boost... and I am running out of fuel again. I've already got the Jet drilled out to .107, and the metering rod fully retracted.

I need more fuel! Anyone have any suggestions? I can open the jet more (not a whole lot, going to run out of material) but I am afraid I am going to be WAY rich at part throttle...

And don't say 2bbl.

 

[TCIC 300ci superbeast]

take a 2LT fill it full of gas and poke a hole in it. then place it over the carb and let it fly.

 

[Bort62]

take a 2LT fill it full of gas and poke a hole in it. then place it over the carb and let it fly.

Well, from the pictures on your websites, that does sound like the sort of approach you would take, but I am going for something a little less rigged...

Now if we can just keep this thread on a semi-serious technical track...

 

[TCIC 300ci superbeast]

all right srry about the joke but i used propane. and that was a staged pic i really dont have it set up like that. now the propane wouldnt be a bad idea for you. just runing with out LP its 750rpm with the LP its 1000-1250
and LP is around 110 octan.

 

[350kmileford]

Get a bigger-stock carb?

 

[Anonymous]

So, I think I fixed my acc pump problem by removing the ball and weight as well as stacking some washers on the pump plunger to push it down farther.

I've got a healthy squirt now. No more starting problems, either.

So I turned up the boost... and I am running out of fuel again. I've already got the Jet drilled out to .107, and the metering rod fully retracted.

I need more fuel! Anyone have any suggestions? I can open the jet more (not a whole lot, going to run out of material) but I am afraid I am going to be WAY rich at part throttle...

And don't say 2bbl.

Go with a YF off a truck. Its got 215 cfm's and it should fit under your hood.

Later,

Doug

 

[Lazy JW]

The Jet in my YF on the 300 six will take a LOT bigger drill size than .107"

I ran a .125" through one but had too much fuel so replaced it with another stocker.

Dunno if a jet from a 300 YF would fit in the smaller carb or not.
Joe

 

[grocery getter]

if you had to take the ball and weight out to get it to run.... the carb has issues. I have some carbs in the shed. What do you need? i'll see if I have it.

 

[Stubby]

I don't know what the limitations of the needle and seat are. Linc ran into a problem with the Holley neede and seat starving the jet. When the engine stops responding from jet changes, you might consider the other possible restrictions.

 

[Bort62]

Thanks for the suggestions guys.

It is a YF from a 300. I could open the jet up a lot more, but it just doesnt seem right.

I was just wondering if anyone had any other insights. I couldnt get a good acc pump shot w/ the ball and weight in there. I think there is a solid chance it was the incorrect weight and/or ball.

What is the purpose of the ball in there anyway? What exactly is it checking?

 

[grocery getter]

the ball is a check valve that stops the fuel from going back into the bowl.
you really need it, i'd fix that first. then i'd up the fuel pressure.

I checked my stock. all that I have are three D0***** motorcrafts from 200's.
Time start thinking fuel injection 8)

 

[drag-200stang]

This road's been traveled down a lot - it's called the "Linc's Highway". I say add 2 more YF's and be done with inadequate fuel problems.

 

[Bort62]

Ill go EFI before I screw w/ multi carb.

Fuel pressure isn't going to change anything. Because the carb is a passive device, as long as there is fuel in the bowl, it doesn't matter what the supply pressure is (relative to vent pressure).

I guess I am stuck hogging out the jet. In retrospect, I wish I had chose a carb w/ a PV. Having to open up the only jet for WOT enrichment is going to tank my mpg.


The 1940 has a PV, right ?

Or I could just fill my WI tank w/ methanol...

 

[Bort62]

I also should make clear that I'm not having any problems filling the bowl (yet).

I am having trouble getting the fuel from the bowl into the motor. The lack of WOT enrichment circuit makes it hard to get the fuel I need under boost w/o getting fuel I don't @ part throttle...

 

[TCIC 300ci superbeast]

so your saying @boost it not leting all the gas out?
if so find out how to put boost in the bowl.
or get an acc. cam with more lift at wide open and arond the same at idle. i dont know if they make one but if your good with a file you could make your own

 

[Bort62]

so your saying @boost it not leting all the gas out?
if so find out how to put boost in the bowl.
or get an acc. cam with more lift at wide open and arond the same at idle. i dont know if they make one but if your good with a file you could make your own

You clearly don't understand the problem.

 

[TCIC 300ci superbeast]

ok then explain it to me

 

[grocery getter]

have you messed with the metering rod? that will be your best bet on controlling the fuel. I read it's fully retracted . you can drill the jet and put in a different metering rod.


you need to address the lack of a check ball. you're not getting the full cc shot of fuel without it.

 

[Lazy JW]

....

I guess I am stuck hogging out the jet. In retrospect, I wish I had chose a carb w/ a PV. Having to open up the only jet for WOT enrichment is going to tank my mpg....

Hmmmmm...... this is stepping pretty far out of my experience so I'm just guessing here.

The YF carb uses a "stepped" metering rod with the main jet for enrichment. This mechanism is connected to the diaphragm with a spring loaded contraption which pulls downward on the metering rod under high vacuum conditions. The throttle linkage lifts the metering rod and the diaphragm spring contraption tries to pull it back down if the vacuum is high enough.

Perhaps a different metering rod with a larger "step" would help. Maybe a bigger "major" diameter and a smaller "minor" diameter in combination with an appropriate main jet would allow enough fuel at WOT but also would lean it out enough at cruise. Just guessing.

I haven't paid enough attention to remember if your turbo is draw-through or blow-through. Perhaps the boost is messing with the pressure differentials enough to just not be compatible with a YF.
Joe

 

[Bort62]

Thanks Lazy - that gives me some ideas.

Gg, I am going to hit the yard this week and try to scavenge a new check & weight. I think the one I had in there was the wrong size. I am getting a pretty healthy squirt right now, but you might be right.

The setup is blow through, and the crux of the problem is mass flow vs volume flow. I am getting a lot more mass flow @ the same volume flow, hence I need more fuel flow area to compensate.

Changing the relative diameters of the steps makes a lot of sense tho. Because the metering rod pulls out of the jet as the throttle opens, it is in effect the WOT enrichment circuit. I did not however notice any mechanism by which vacuum would pull the rod down, it appears to be fully mechanical.

I tightened the metering rod adjustment screw all the way, causing it to be at it's full retraction when open. Perhaps what I need to do is, as you suggest, reduce the diameter of the tip section in order to increase flow area as the rod retracts. Wish I had a mini precision lathe available

I don't think its a pressure differential problem, It runs ok... it's just as the boost comes on, it starts bucking and sputtering 'cause it is going lean. At the lower boost setting (3psi) I was able to fix this by drilling out the jet. As soon as I turned the boost up, it started doing the exact same thing again once the boost goes over ~ 5 psi.

I think next I will try re-setting the metering rod to factory position, and reducing the diameter of the tip. I might just remove it entirely, but that may cause it to pop out of the jet and bind up when I retract it. I wonder if I still have any Qjet rod's kicking around...