4A084 carburetor

[cranetruck]

Question, would a "new" carb from Saturn or other dealers be considered fresh or will they need to be rebuilt?
Can't find rebuild kits anywhere and may have to save up for a new carb....
TIA

 

[DieselBob]

I would consider them "fresh" ready to run. I know that gaskets will dry and shrink with time but that seems to happen most when they have been exposed to gas/oil/diesel for a while first.

 

[PeterD]

My experience has been if they are not disassembled they will be OK. Take them apart (even to inspect) and you have a high likelihood that the gaskets will not fit when you reassemble! As Bob says, this is most common when they (the carb/gasket) has been exposed to fuel.

 

[PsycoBob]

I know the bowl gaskets on both of my 2a016 carbs are cork- easy enough to make a replacement, if needed. Note: tiny ring gasket around the center post housing the jets- don't forget that one!

Input/output flanges look to be something else, but making a flat gasket for them should also be pretty easy. If you pull the adapter that connects the airbox hose to the carb body, it'd be pretty easy to trace it. Hopefully your carb is similar.

 

[cranetruck]

....... Note: tiny ring gasket around the center post housing the jets- don't forget that one!.....

Right, did that and used a small O-ring for the center post. Don't know if I have the correct fit, though.
Engine runs beautifully, it's just the starting that is questionable, need to use ether and don't like it, even after it has been running and is restarted after an hour or so.
Checked the fuel pump and it builds pressure...

 

[PsycoBob]

My little 1.5k set worked for a while, until the float started sticking (rubbery fueltank sealer) with a few simple steps. Running on a new boat gas tank, w/ new hose & priming bulb.

Open fuel valve, set fuel lever to correct position. Squeeze priming bulb until I see activity in the filter bowl, flip fuel-pump lever 10x, set choke full on (mine vibrates to half-choke as soon as the engine starts), check position of 'run' switch, wrap and pull.

Started first try every time for a week- then the rubbery coating on the float stuck to the inside of the bowl, and caused the pump to dump fuel out the air filter.

With my spare engine & carb, I'm looking hard at conversion to propane- this will eventually be mounted on a camper build.

 

[callbt]

Hello, My MEP-018a is up and running, but similar to others, hard to start. Once running it "smells" like it's running rich. Is there a way to adjust the carb on these units (4A084 engine with 124 hrs). I've had the carb apart twice- the last person that put this unit away right ~10 years ago..... so cleaning was not neccessary yet still took it all apart and soked/blew out holes.

thank you,
Brian

 

[jbk]

this carb. has a fixed main jet nothing to adjust only the idle can adjust. do you still have the oring around the bottom of the main jet nozzle? when you pull the main out it usually damages it. these carbs. are still available for 40 bucks from saturn surplus.

 

[cranetruck]

Hello, My MEP-018a is up and running, but similar to others, hard to start. Once running it "smells" like it's running rich. Is there a way to adjust the carb on these units (4A084 engine with 124 hrs). I've had the carb apart twice- the last person that put this unit away right ~10 years ago..... so cleaning was not neccessary yet still took it all apart and soked/blew out holes.

thank you,
Brian

Here is a page from the TM 5-2805-259-14.
Made the adjustment last Summer, but didn't notice mush difference in starting, still a bit fickle.
Have been running it about 20 hours total since last May and it has been starting okay, but after a couple of weeks of cold weather (15 to 32°F), it now won't start at all, not even with ether. It has spark and fuel, so not sure what's going on...will check compression next...

 

[jbk]

the plugs foul easily. i adjust the choke sol. about 3/4 closed cold. when i start cold i manually close the choke all the way closed while turning over until i get a putt out of the engine, then release and let the sol. take over.

 

[cranetruck]

the plugs foul easily. i adjust the choke sol. about 3/4 closed cold. when i start cold i manually close the choke all the way closed while turning over until i get a putt out of the engine, then release and let the sol. take over.

Thanks.
Hmm...I'll check the condition of the plugs, the spark looked a bit weak...

 

[liftman]

I have disconnected the electric solenoid and choke manually. Full choke when cold until it sounds like it wants to start, then about half until it runs. Then push choke all the way in.

When it's warm, I have found that it will crank and crank and not start unless it gets about half choke for a couple seconds of cranking.

I have had the carb apart to check for varnish, but didn't find anything.

I only run mine every few months, and that's the way it has always started, no matter what the ambient temperature is. I just assumed that is the way it starts. It seems that all of them start like that by this thread.

 

[cranetruck]

Liftman, that's the way I choke mine also, the automatic choke is disabled.
It has started in about 5 to10 seconds until last week. Yesterday after having to use ether, it took its time to get up to speed and I lost the regulator, possibly as a result.
There are ultralight sites where they discuss and modify the 4A084 for their aircraft applications that offer some good reading.

 

[68impalass]

if this engine is the one on the MEP-018 remember the oil pressure must be up before the engine will fire. To test jump the low oil pressure sensor and see if it starts

 

[cranetruck]

if this engine is the one on the MEP-018 remember the oil pressure must be up before the engine will fire. To test jump the low oil pressure sensor and see if it starts

The oil pressure switch is out of the circuit during the starting op.

 

[callbt]

Hello,
The MEP-018a is wired and WAS running after I got the spark plug wires installed correctly- I had been following the wiring as received from the previous owner- two wires crossed, starts MUCH easier... well did. The governor shed some parts-
any one here have a reason for this type of failure? Luckily the roll pin sheared ( added debris to my oil) but I can't really find what part of the governor failed- can any one shed some light on this type of failure and how to prevent it ?

 

[liftman]

Somethng similar happened to me. The screw at the bottom of the magneto that activates the impulse coupler backed out and caused the gear to bind somewhat. This binding did minor damage to the magneto gear and the plastic governor gear. The damage was able to be repaired with some careful filing of the gears. The screw that backed out was put back in with some Loctite.

I noticed something was wrong because of a whining noise from the engine. That's how I became aware before a lot of damage was done.

 

[callbt]

Hello,
Thank you for the feedback. The engine is loud and with ear plugs in I didn't notice anything until it was already busted.

My "nut" that holds the magneto gear to shaft is off- fell out as I removed the governor. The real puzzler is that the holes for the wear
posts that mount inside the fly weights are both cracked- yes I'll get some pictures soon. I'm suprised the plastic gear
didn't have damage- just the roll pin sheared off.

Is there supposed to be a nut and washer that holds the plastic gear to the governor's shaft? I'm thinking the previous
owner dropped the nut thru the circular oil drain/cut on the governor and I've been lucky the parts didn't bind before now.

Sincerely,
Brian

 

[hndrsonj]

Bjorn, What did you wind up doing with your carb? I see Army Surplus Warehouse has the carbs for $19.99 on their site.

 

[liftman]

It's been about three years since I had it apart, so I really don't remember. The TM shows a washer and snap ring holdng the gear on the magneto. But it doesn't really show anything holding the plastic gear on to the governor.

Sorry I can't help anymore.