MC 2150 empty bowl

[BeagleRock]

Remanufactured Motorcraft 2150 has very little fuel in bowl after sitting overnight. I recently put an aluminum spacer on it as the original synthetic plastic one was slightly warped. I also put one of the carbon fiber 1/4" gaskets on the bottom and a 1/32" on top of the spacer, well that made the carb sit up too high and made the throttle cable fit on the shaft at an angle which created a binding sensation meaning once you had it passed the initial travel it was OK.
 So I ordered 2 of the 1/32" flange gaskets to drop the carb down to where it would be even with the cable as to create a smooth throttle pedal action. Well what I discovered was very gas soaked gaskets upon removal of the carb and spacer. Also the fuel bowl didn't have much in it as I almost had to turn it 90 degrees towards me to get some gas to run out of the inlet opening.
 This is making me think that whatever the reason is for low fuel level is also why I have a tough time getting it started after sitting for a day or more. I don't see any damp spots around the PV. Anyway that's my story for today 🙁 83 351W

[Gary Lewis]

If the power valve is blown or its gasket is leaking the leak will be to the inside of the carb, and you'll get essentially the results you are seeing - wet gaskets and a dry bowl.  Plus hard starting.

Or, if yours has the remote PV sensing via a vacuum hose, it'll run into the intake manifold via the hose.

[BeagleRock]

Gary you never have good news for me
😉

[Gary Lewis]

And that's my fault?  

If yours is the remote-sensing PV you can remove the hose from either the carb or the manifold after turning the engine off and see if the PV leaks.

Hmmm, maybe that's why they went with the remote PV feed.  They'd had so many of them blown they needed an easy way to test?  

[1986F150Six]

Gary Lewis wrote

Hmmm, maybe that's why they went with the remote PV feed.  They'd had so many of them blown they needed an easy way to test?  

Had your afternoon coffee, yet?

[Gary Lewis]

Yes.  Does it show?  

[1986F150Six]

No, I was thinking you needed some!

[BeagleRock]

No I was kidding hence the 😉

[BeagleRock]

Need something!!!  😀

[BeagleRock]

Mercy sakes alive it's HOT down here in the Gee... fortunately I had a spare PV 6.5 whatever that means. No remote vacuum on this one so I'll change it and check back in shortly. 105 heat index yikes!

[Gary Lewis]

79 degrees here in 'took.  And a t-storm.  

6.5 is the point in inches of vacuum where the power valve opens.  Above 6.5" it is closed, but below that it'll be enriching the mix for power.

[JMUBullnose]

Interesting - I have potentially blown PV on my trouble shooting list as well for the 2150.

I worked on the truck over the weekend and haven't driven it since Sunday. Last two days as it sat in the driveway I would occasionally get whiffs of fuel when walking by it while working in garage or in yard. No puddles under the PV that I could spot but that could also help explain some of my hard start issues as well.

[Gary Lewis]

PV's, and fabric accelerator pumps, are the achilles heel of Holley or Holley-type carbs, and the 2150 is one of those.  The original design was flawed as it allowed manifold vacuum or pressure to get directly to the power valve such that a backfire through the carb would frequently blow the PV.  A fix for that error was finally applied to new Holley carbs as of 1992 and is available for retrofit to the bulk of carbs that don't have it.  But I don't think it was ever applied to the 2100 or 2150 as they were out of production by '92.

Sitting at the bottom of the bowl, as the PV does, when the fabric is blown two things happen.  First, when the engine is running the vacuum usually can't overcome the spring and the valve stays open.  At first blush that would seem like it just causes the mix to be rich by however much fuel can flow through the PV's orifice(s).

But, the second thing is that there is now a direct path from the bowl of the carb, through the power valve & its diaphram, and into the intake.  So, when the engine is running gas is being pulled directly into the intake.  And when the engine is off gas runs out of the bowl into the intake and the bowl is dry when you try to re-start the engine.

[BeagleRock]

Very in depth explanation, I appreciate it and need all the help I can get. Heading to my old Hometown of Webbers Falls tomorrow to work on a lawnmower, something I KNOW about lol. I hope the Bluebird of Happiness gets me there and back safely!  

[BeagleRock]

Join the dry bowl syndrome club 😉

[Gary Lewis]

Good luck!