2.2L Carburetor Issue

R

Ramjet555

Newbie
Joined
Jun 11, 2019
Messages
94
Location
Winnipeg, Manitoba
Aircraft
RAF 2000, airplane & helicopter
Total Flight Time
+6000
I have a regular carburettor 2.2L and noticed the engine would not idle less than 1500 rpm and ran rough.
I cleaned the plugs and it seemed to be running rougher.
I shut it down and got some kind of hydro lock, crank did not want to turn over.
Pulled the plugs and the cylinders had fuel swimming around the top of the pistons.


Recently I changed the two fuel pumps for exactly the same make and model.
Carter P74022 in-line electric fuel pump rated at 5.8 to 8.7 psi.

I would appreciate any advice on what needs to be serviced, or replaced.
I see its a Holly Carb. Would anyone have the exact make and model?

Is there a kit for reconditioning it?

Any direction appreciated
 

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That's a model 0-4412S 500cfm, or 0-80350 350cfm, you can buy rebuilding kits for $50.00 to $100.00 dollars from Holley or any of the auto parts stores. A new one is anywhere from $450.00 to $500.00.
 
Dear Sir,
your max pressure for the 2bbl Holley is 4 PSI, The float valve is overcome and hydro locking the engine. Try 3.5 to 4 max.
Phillip
 
Both models require a float level adjustment to prevent flooding as well, see Holley data. Rough idle is affected by idle jet adjustments, there are two, one on each side of the carb, these meter fuel and air bleed for the idle. Again refer to Holley set up instructions. It’s is not difficult. The main mixture is controlled by two stamped jets, 68 to 70 was correct for my setup to make sure a WOT setting at takeoff was about a 13:1 ratio and idle was 14.3 :1 air fuel ratio. How do I know? I installed a fast reading fuel/air sensor 12 inches from the exhaust port to display the reading on an electronic meter from Summit racing.
Thanks,
Phillip
 
In my experience with carbureted engines if the float or the needle and seat aren’t working well; raw fuel will pass into the engine.

Some Subaru engines may develop a leak in the head gasket that allows coolant to enter the cylinder and create a hydraulic lock.

Depending on how “some kind of hydro lock” was managed your engine may be damaged requiring an inspection of the rods and rod bearings.
 
Vance said:
In my experience with carbureted engines if the float or the needle and seat aren’t working well; raw fuel will pass into the engine.

Some Subaru engines may develop a leak in the head gasket that allows coolant to enter the cylinder and create a hydraulic lock.

Depending on how “some kind of hydro lock” was managed your engine may be damaged requiring an inspection of the rods and rod bearings.
Click to expand...
Thanks Vance,
Good point that I considered. I pulled all the plugs immediately and sampled what was in the cylinders
and it was raw fuel and only fuel. No coolant. I've ordered 4 psi fuel pumps and looking for a Holly carb kit
 
before shelving those fuel pumps, I'd put in a regulator first. Cheaper and more dependable in the long run (pressure wise AND longer pump life)
Plumb it so the regulator is on the far side of the carburetor, and excess fuel is returned to the tank- or minimally, back into the suction side of the fuel I prefer it going back to the tank to eliminate any air or vapor issues.
You'll always have relatively cool, solid fuel this way.
Don't use the dead head style that simply goes between the pump and carburetor..

I'd bet 99% of your rough idle was the precursor to the float bowl flooding out. I agree on the 4 psi max to the bowl.
I'd look at the condition of that float arm/pivot pin extremely close-
Me and Holley carburetors have a long and miserable history- but I'm thinking a rebuild/cleaning and a NEW OEM Holley float (there IS a chance you have the foam style float which may be saturated by now...(get the brass one!!)
 
Hi Rangerman,
Wow, Thank you. Yes, I seriously thought about just adding a pressure regulator after I had ordered the 4psi pumps.
I've put in the 4psi pumps but like the idea of a fuel pressure regulator.

As you point out, damage is suspected to the Float Arm, Pivot Pin, I will look for the Foam Float

I called Holly and my Holly Carb is a 7448-1 which is on the throttle body, its a 350 CFM
Holly have a repair kit on a 3 month back order... Great.
I wonder if anyone knows where I can get a kit for a Holly 7448-1 350cfm carb.

I have the carb still on the bench and was planning on opening it up very carefully to check for damage.
The key symptom is that the 10psi pums have resulted in cylinder heads full of fuel.

The new pumps have a flow direction that is opposite the 10 psi pumps. I had to pump fuel just to
prove the arrow on the side was correct. No document sheet came with the pumps, it pumps at over 1 liter a minute
and is a slightly smaller dia from originals, I had to use the clamps that came with the new 4psi pumps.
 
I had a simular problem on my RAF.
The intake gaskets were leaking, sucking air.
I used a can of carb cleaner to find the leak, while the engine was at idle I sprayed the carb cleaner on the gasket area & the engine would run smooth.
 
Chances are, it's just the tip/seat of the needle valve pounded out or the heavy float. But it's still good practice to examine the pivot shaft/float arm for scoring. It don't take much to 'hang up' a float!!

Picturing in my mind the proximity this carb is when mounted in place of the original TB. It may be in an arc of natural engine movement that shakes the carb a little more than one nested closer to the crankshaft.. resulting in a little more frequent carb rebuild.

I've seen electro oil pressure sensors mounted off the back of the engine getting it's liver shook out in less than a few hundred hours.. Not saying you need to re design the intake system- Just maybe be prepared to overhaul it a tad more often!
Is this carb still available new? Edit- Holley says "out of stock"
There are a few vendors on Amazon that list them for about 550 bucks. Yikes.
- Don't get a rebuilt one!!... you may have to go through several before you get one that isn't buggered up.

Also on amazon- several rebuild kits for your 7448-1. $35-50 bucks.
 
Rancherman, I can't find any rebuild kit for a 7448-1 on Amazon.
Can you post or send me some links?

It would be nice to have a pre-made gasket set on hand prior to pulling it apart to inspect it.
The engine has only done 115 hours in 20 years.
I'm wondering if the 10psi fuel pressure has damaged it.
I suspect that the leak or overflow got worse in a few minutes of running rough.
Would not low idle and new plugs were black.
I now regret cleaning them on the aircraft spark plug blaster cleaner.
They probably just needed a wash in avgas or brake cleaner.
 
Ok, the new carbs were on amazon.. Ebay had the multiple listings for the kits.

www.ebay.com

holley 7448 1 rebuild kit for sale | eBay

Get the best deals for holley 7448 1 rebuild kit at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!
www.ebay.com

Both the 7448, and the 7448-1 use the same kit. regardless of the 'dash' number.
Be aware some of those ebay listings are for commonly modified carbs, and may have a gasket or 2 that's been opened up for bigger power valves.
Some classes of circle track guys using this carb are allowed modifications...

It'd be nice to know if YOUR carb has been 'done' in this regard!

But, GyroChuck's post DOES use genuine Holley parts.. I'll sleep better knowing you used that instead of a knock-off!!

Most people think the float drops to allow fuel in... then it shuts off when full.
Only partially true. On a running engine, it only really regulates the flow to be exactly the amount being burned.. so it's seeing a pretty tight clearance as fuel is squirted past.. This close proximity, vibration, and possibly today's fuel tend to erode the tip over time.
Pretty soon it simply can't shut it down until the fuel is waaaay too deep in the bowl.
 
I made a gasket and the carb ran nicely. I adjusted the throttle cable and
then next start, both rear cylinders stoped working.

I suspect the coil has failed. It ran rough and disconnecting the rear cylinders made no difference.
Has anyone experienced a sudden coil failure on the two rear cylinders?
Just in case I've wired it in error, both forward coil wires go to the front cylinders either side and
the rear wires go to the rear cylinders.

The former owner had frayed the throttle cable and used two washers instead of a hole thru the bolt.
I'll try a repair to the frayed cable tomorrow. Plan is to embed some resin, then cut off the worst and file
it clean till it fits thru the hole in the bolt.
 

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Alternate idea on the cable: heat 'til red hot, then twist with drill to break the cable in the red hot zone.
Leaves a nice pointy cable that is not frayed.
See EAA videos for more in-depth information.
 
swap the coils... see if the problem follows the coil, or if it stays with the rear cylinders.

I don't know that coil pack- is it a shared bank, where both plugs fire at the same time? 'wasted spark' type deal?
You'll see quickly if it's isolated to the coil, or the impulse/power circuit.

Grab any known good sparkplug and hook it up and ground it against the block (leave the original sparkplug in the head) crank it and see what's what with the spark.
 
Thanks Rancherman,
I did swap the coils or the leads to the coils, both rear were not working.
I assume no spark from the leads, Yes, I should have held the plug next to the block and watched
the spark. I did not.
I just pulled the leads off the two rear cylinders and it ran just as rough.
The plugs show a good spark in a tester.
I've got a new coil block ordered via amazon however I doubt that it is the cause.

There are 3 wires going to the coil block.
If that is binary wiring, it would also knock out 1, 2 and 3.
So I'm assuming I've made some mistake somewhere .

I hope to get at it after work tomorrow.
 
Rancherman, I read that there is an ignition module for the 2.2 L engine?
I'd like to get a new one just zero time that component.
would anyone have a link to Amazon for the correct ignition module?
and a link to the Crank Censor?
 
Here is a link for the Subaru 2.2 engine manual.

www.manualslib.com

Engine - Subaru EJ22 Repair Manual [Page 41]

Subaru EJ22 Manual Online: Engine.
www.manualslib.com www.manualslib.com

I had a Subaru 2.2 on my Gyro. Mine did not use the crank sensor. The plug spark was triggered by the distributor.

I can not find the info on the ignition module. I'll check at the airport next time I'm out there.

Caution on the ignition module. Some types have a Rev limiter built into them limiting the maximum rpm for the engine. Found that out the hard way. Couldn't get the engine over around 4000 rpm.
 
 
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