Motorcraft 2150 stamped 1.08. Enough for stock 302 in 78 F100?

[Craigwell]

ordered a set of #60 jets as well, we'll see what results come from the 2300. I will try the 2150 again with the manifold vacuum hooked to the power valve assembly. I did have 20" of vacuum when checked at stable idle with the 2150 a few days ago. How exactly does that power valve work? As manifold vacuum drops with throttle, does the lower vacuum allow less fuel to pass through the power circuit, while the increased airflow through the venturis pulls more out of the main circuit? The symptom I had a few days ago with 2150, no vacuum to power valve: At part throttle, it seemed to stumble and want to backfire as if it was receiving too much fuel. Does that sound about right? Cheers. I will be back at this in a few days with the 2150 and will report back for posterity! (Anyone looking at my posting history, with all that free time on their hands would see I'm big on posterity.. and posteriors)

[Jermafenser]

Steady 20" Hg is excellent.

I'm not sure, but I think the external power valve was part of emissions that had a vacuum reservoir. This is circa 1980's. I also do not have the knowledge to diagnose such thing, as well. But I think you may be right. Power valves need the proper A/F mix. Not having the external vacuum sources may richen the mixture and cause the issue you described. That's my take.

[Craigwell]

hmm I don't like the reservoir tie-in idea. There is an odd looking unit on the front of the carburetor, right between the accel pump and the fuel inlet filter. Looks like a bit of a dashpot itself. I also had this plugged in my first go-round, and will leave it plugged when i try the power valve-to-manifold vacuum connection.

Glad I ordered the Holley Jets, as I realize I might need the 2300 after all, unless a good old 2100 hits me on the head. Thanks

[Craigwell]

here's a useful pic:

Google Image Result for http://www.carburetion.com/diags/2150diag.jpg

The piece I'm talking about is #51, a "pump relief valve assembly"

I'm thinking vacuum pump relief valve?? emissions stuff I can disregard for the time being.. We'll see. going to bolt the 2150 back on this weekend.

[Jermafenser]

Originally Posted by Craigwell

here's a useful pic:

Google Image Result for http://www.carburetion.com/diags/2150diag.jpg

The piece I'm talking about is #51, a "pump relief valve assembly"

I'm thinking vacuum pump relief valve?? emissions stuff I can disregard for the time being.. We'll see. going to bolt the 2150 back on this weekend.

Ah, a 2150A. I never knew such thing existed. I primarily deal with '70's and earlier plain-jane 2150s.

That's a new thing to me. I can't offer any help on that. But judging from that picture, it may be a feedback carburetor?

[Craigwell]

It came from an 83 or so LTD Wagon with a 3.8. I tried it again yesterday with the power valve hooked up to the vacuum port in the spacer below the carb gasket, and it didn't want to work well at all. Worse than when I had the power valve unhooked period. It is meant for manifold vacuum, not ported?

You may be right about the feedback angle, uncertain. I may try it with another vacuum source, but I can't see how what I used for a source wasn't sufficient.

Thankfully a kind neighbour had a set of holley jets, so today I get to go from #58, 60, 68 to 70 in the 2300 and see if I can get it happy. Unsure if the holley has the appropriate power valve for this application.

I still want a 2100 to hit me in the head, but nobody's thrown one at me quite yet. I'm looking.

[Jermafenser]

The port in the spacer below the carburetor is for emissions (evap canister, actually), not a vacuum source.

You want to hook up either a ported or manifold vacuum to the power valve cover described in #39 in the link you provided.

I have quite a few 2100 cores I'd be willing to let go. PM me if you are interested.

[Craigwell]

Things seem to be better with the 2150 at the moment. Holding steady with 20" vacuum, with idle screws backed out about 2 - 2 1/2 turns for max vacuum. Runs the best at this point, even a bit high on rpm with idle set screw almost backed off entirely. the ported vac advance is still bumping it several degrees at this point, in turn raising the idle more.

More on that in a moment

I'm still having a bit of trouble with the tip in. Wants to stumble and backfire after a few seconds, smells rich.

I will confirm the jetting, and can order some online at this link:

Ford 2V Parts Page

Does anyone have an idea of what might be an ideal jet size for the 2150 in this application??

I have confirmed that what I was using on the 2150 for the power valve is a legitimate vacuum source, but will still try another manifold vacuum source to try all options.

Back to timing, I'm also opening up the dizzy to confirm what mechanical advance it has, and at what rate. I'll look at the vacuum advance as well, and may back it off a bit. It is almost running well, and the way I see it, it could still be a tune issue with the 2150, or could be timing. Some poor soul took the timing pointer off this engine and I need to find one.

As for the Holley:

Last attempt: Couldnt get more than 13" vacuum, and it fluctuated down to 10 and back. Still extremely rich at idle, with #58 jets.

The power valve is stamped 5.0 .. opens at 5" vacuum.

I think it has other issues I'm not interested in exploring at the moment.

[Jermafenser]

No idea on jet sizes, it varies...and there are no markings on the jets I have removed from 2100/2150s. I think you may need to measure them somehow.

In my first post in this thread, it calls for 49F jets on a '78 F100.

[Craigwell]

Sorry Jermafenser, lost track of that bit in all the fun. As far as getting the idea of the jet sizes, maybe I'll just order a set of 49's for the heck of it, and see what they look like in comparison to the ones in the 2150 now.

Thanks again

[Beanscoot]

That Carburetors Unlimited site wants ten bucks for a pair of jets, isn't that a little steep? Does the 2150 use Holley style jets?

Here's a link to 36 pair of Holley Jets for $51:

Amazon.com: Holley 36-181 Jet Assortment Kit: Automotive

And you would be a good candidate for this nifty conversion piece that lets you change jets without taking the float bowl off (save gaskets) for only forty bucks:

Holley Quick Change Jet Kits - JEGS

They don't mention use on 2V carbs but it might fit some. My 2V Holley has the center hung float bowl on it.

Another approach to take is to get a pair of jets and fill up the holes with soft solder, and just drill out as you wish. If they seem too big, solder them up again and redrill smaller. You should have a set of 1-60 drills (about .22" down to .040" IIRC) to do this.

[Craigwell]

That is a handy looking jet changing setup.

the 2150 jet sizes arent the same as the holleys. smaller threaded units.

[Craigwell]

I'm picking up another carb, a 2100 or early 2150 from a 302 this weekend.
I am recurving my distributor slightly in the meantime. If I cannot get the 2150 I have to work well, I'll rebuild the one I'm purchasing and try it and compare.

[Jermafenser]

Keep us updated.

You ought to rebuild it anyway. Who knows where it's been? It's not that hard to rebuild one. If you run into a snag, I'll help.

What about the Holley 2300?

[Craigwell]

I've rebuilt early model 2100's before with no issues, the 2150 I have now might prove a little more intricate, so not too keen to open it up.

The Holley seems to have a major issue, and I'm not interested in touching it again right at this point. Last test with #58 jets still had it dumping way too much fuel in, with only 13" vacuum at surging idle. Maybe the 5.0 Power valve is shot, but it sure looks fine, brand new carb and all.

I do plan on keeping it though, as it may see duty on my 76 at some point. I'm trying to keep things real simple right now, as I would like to have the truck on the road in a couple weeks, and that 302/C4 might just get yanked in favour of the drivetrain from the 85 truck in my sig.