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 Where's this dirt coming from? MC-2150 
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Joined: Sun Jun 23, 2013 1:41 pm
Posts: 366
Location: Phila. Penn.
There's lots dirt in the bottom of the bowl of this carb. Where the heck is it coming from?
It is a stock application, but I'm stumped. Only about 20,000 miles since the last cleaning and fuel filter replacement.

Motorcraft 2150 (AMC-Jeep version)
Cut open the old fuel filter - nothing in there. So that seems to rule out pump or feed line deterioration.
Soft fuel line to carb is newish (last decade, not original)
Float discolored but no obvious (to me) deterioration.
Accel pump umbrella valve distorted (in housing) but it's orange not black.
Inlet needle valve tip also looks OK.

Could the bowl somehow see lower than atmosphere pressure and pull dirt out of the vent hose? (Vapor Emissions control equiped vehicle)


Attachments:
File comment: Accel pump valve
2014-Sept-1-MC2150_12-reduced.jpg
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File comment: Dirt
2014-Sept-1-MC2150_06-reduced.jpg
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File comment: Dirt in bottom of bowls
2014-Sept-1-MC2150_02-reduced.jpg
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Wed Oct 01, 2014 7:25 am
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Joined: Thu Mar 28, 2013 6:09 am
Posts: 726
Is it dirt or?? Does it have a charcoal canister???Vent on top to it?


Wed Oct 01, 2014 9:59 am
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Joined: Sun Jun 23, 2013 1:41 pm
Posts: 366
Location: Phila. Penn.
Yes it has a charcoal cannister. You think it could be sucking charcoal into the bowl? I'll say the black stuff did not feel gritty in my fingers.

The 2150 has an vent nipple on the bowl cover. On my Jeep the vent hose is connected to an electrically actived valve and then to a vapor separater and then to the charcoal cannister. The vapor can also goes to manifold vacuum in the PCV valve.
This is the emmission's diagram from my waggy (posted on Tom oljeep's website).
Image


Wed Oct 01, 2014 5:53 pm
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Joined: Fri Feb 08, 2013 2:37 pm
Posts: 1704
The red rubber check valve curling up like that is because it is the wrong material to be resistant to ethanol or perhaps the use of a fuel system cleaner with a high content of aromatic compounds or MEK. The black stuff looks like the interior of rubber hoses which are shedding material because of exposure to incompatible solvents.


Thu Oct 02, 2014 1:39 am
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Joined: Sun Jun 23, 2013 1:41 pm
Posts: 366
Location: Phila. Penn.
That's what I first thought, but there's so little rubber hose from the filter to the carb it seemed unlikely. All I can figure now is that maybe disolved glue from the filter itself plus bits of rubber and float material. Deterioration might be more time dependent than milage dependent. Most of the fuel has been Sunoco branded (93), with some Hess, Lukoil, and Shell. This summer mostly Sun and Shell.

Looks like I better make carb cleaning an annual maint item. Put new float, inlet and check valves in, but they were left over from 5-10 years ago. Might not hold up with current fuel. :(

FWIW attached is a pic of the filter cut open, and also a picture of the cluster in case anyone is curious about Motorcraft carbs. I don't think 2150s see much racing use, but at least some off-roaders like them. My trail driving is pretty tame so I can't comment on that.


Attachments:
2014-Sept-1-MC2150_10-reduced.jpg
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2014-Sept-20-fuelfilter-reduced.jpg
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Fri Oct 03, 2014 10:09 am
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Joined: Fri Feb 08, 2013 2:37 pm
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There is hose from the tank to the steel line and hose in the evap system. Perhaps the rubber dissolves in the fuel and passes through the filter, then agglomerate into those chunks when it sits in the carb.


Fri Oct 03, 2014 3:14 pm
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Joined: Sun Jun 23, 2013 1:41 pm
Posts: 366
Location: Phila. Penn.
So the cat came back, I thought he was a gonnar but .... a few months later, same problem.
Turns out the foam in the fuel vapor canister was starting to disintegrate. There is a solenoid valve that shuts off external fuel bowl vent when the engine is running. However whatever seal was on the tip of the solenoid's plunger is gone. So, it was definately possible for the charcoal and other bits to get drawn into the fuel bowl. I'm going to try to fix both of these.


Wed Jan 21, 2015 11:45 pm
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Joined: Sun Jun 23, 2013 1:41 pm
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Location: Phila. Penn.
barryh wrote:
Is it dirt or?? Does it have a charcoal canister???Vent on top to it?

So you're the winner Barry. Your first guess was the right one. I found it hard to beleive that the charcoal could work its way up and through the hoses, passed the closed valve, and into the bowl. But it did, and in great quantity.

Even with the valve open, there ought to be little pressure differential between the cannister and the bowl. However perhaps even with a 2 bbl, long uphill runs at a good 1/2 throttle, the snorkel and aircleaner could be restrictive enough to create a depression. Add into the mix some off road that would shake the and toss the charcoal into the air chamber at the top of the vapor can, and we have the recipe. Final topping was that the charcoal probably floated pretty good until the jeep was parked and shut off, then it settled.

The canisters are no longer available. I chisled off the weld or glue holding bottom on. Also popped the secondary purge to replace the rubber diaphram which seperates manifold and ported vac. Here's the original foam at the top.
Attachment:
File comment: Original foam filter in top of charcoal canister.
Vapor-Canister-19-reduced-c.jpg
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The solenoid valve is also no longer available. Figures. This was a bigger pain to open and a lot more head scratching to replace the plunger tip. I *think* it will work. Find out in a couple hours.
Attachment:
File comment: Carb vent solenoid valve with charcoal inside.
Solenoid-Valve-repairIMGP0008-r-c.jpg
Solenoid-Valve-repairIMGP0008-r-c.jpg [ 90.69 KiB | Viewed 568 times ]


Sun Feb 01, 2015 9:53 am
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Joined: Mon Dec 29, 2014 1:26 am
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If you're getting liquid fuel in the charcoal canister you need to look at how the fuel lines are routed, it shouldn't be able to do that. Either the tank is getting overfilled or the lines are routed wrong or the canister is mounted too low. There was a similar line routing issue with, I think, some Ford vans. And some more recent GM trucks, but I think the cause there was owners trying to force in more fuel after the pump nozzle's auto-cutoff. Same result in both cases: liquid fuel in the canister let charcoal bits escape into the rest of the system and create havoc.

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Sun Feb 01, 2015 8:22 pm
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Joined: Sun Jun 23, 2013 1:41 pm
Posts: 366
Location: Phila. Penn.
No sign of liquid in the canister. Interesting idea though. No problem with the layout AFAIK and I have the FSM and service bulletins. I think its just combination of age and whatever is in fuels. I put 60k on it over the last ten years so its not inherent in the design. I mean, geez, 30 years is a long time for a filter foam to last under such conditions.
Not sure what the solenoid valve used for a stopper. I cut down a nylon thingy I had in drawer. Might have been a picture hanger wall anchor. It won't be a great seal, but should be good enough for what it does. The 2150 has two open vent tubes into the aircleaner which should be plenty of air when running.


Mon Feb 02, 2015 1:38 am
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