Jump to content

Nominations for Tractor of the Month
Garden Tractors and Parts on eBay



Photo
- - - - -

Tackled My Carburetor Problem

still not right yet

  • Please log in to reply
19 replies to this topic

#1 Bigfoot OFFLINE  

Bigfoot
  • Member
  • Member No: 11780
  • 20 Thanks
  • 41 posts
  • Location: Ohio

Posted October 22, 2012 - 05:55 AM

Well once again I have been battling my JD 318 carburetor which has been running lean. I've removed the intake manifold, exhaust and carburetor. I cleaned everything up and reinstalled all with brand new gaskets. This time I detected no leaks anywhere, but she still runs lean, it won't idle smooth, except if I close the choke almost completely. However it runs much better starting around mid point throttle , so I'm assuming the low speed jet is plugged some. Anyway I'm tired of messing with it this year, hopefully next spring I'll give it another look see. I might get some carb cleaner and spray it into the carb while it's running as a last resort this year. Also I'm getting some stable gas additive to pour into the gasoline before I put her up for the winter. This 318 has the non adjustable carb, I might find a older carb with high and low speed adjustments to solve this trouble. Anyone had this problem? Any thoughts?
Thanks

Attached Thumbnails

  • engine.JPG


#2 Alc ONLINE  

Alc

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 1094
  • 5,450 Thanks
  • 6,618 posts
  • Location: Bangor Pa

Posted October 22, 2012 - 06:01 AM

Sorry to hear it's still not running right . I know those little passages can be a pain. I had a little snowmobile carb that wasn't running right and I bet I took that off 3 or 4 times until found one hole , (cleaner would blow through it ) wasn't completly open . After cleaning it it ran better . Good luck , Al

#3 LilysDad OFFLINE  

LilysDad

    Cat Lover

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 10443
  • 9,626 Thanks
  • 7,669 posts
  • Location: N. Illinois, DeKalb County

Posted October 22, 2012 - 06:34 AM

Spraying carb cleaner in the throat of a running engine does very little except to make the throttle plate nice and shiny. Sorry!

#4 Cvans OFFLINE  

Cvans

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Member No: 5412
  • 4,483 Thanks
  • 5,013 posts
  • Location: Eastern SD.

Posted October 22, 2012 - 06:51 AM

:iagree: and it can help with a sticking choke and throttle. Other than that not of much use. You'd be better off to spray the contents into a container and let your disassembled parts soak in it.
You're probably looking at a better solution by finding that older model carb with the high and low needles. Most EPA carbs are set lean to begin with.
Good luck.

#5 LilysDad OFFLINE  

LilysDad

    Cat Lover

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 10443
  • 9,626 Thanks
  • 7,669 posts
  • Location: N. Illinois, DeKalb County

Posted October 22, 2012 - 08:20 AM

Most EPA carbs are set lean to begin with.


..... and as the air gets colder in the winter, it get's leaner.

#6 Trav1s OFFLINE  

Trav1s

    Got points?

  • Senior Member
  • Member No: 5472
  • 2,602 Thanks
  • 3,750 posts
  • Location: Cedar Rapids, IA

Posted October 22, 2012 - 10:24 AM

What about a good strong dose of Seafoam in the gas and some light work.

#7 JDBrian OFFLINE  

JDBrian

    Super Moderator

  • Super Moderator
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 2507
  • 9,574 Thanks
  • 14,136 posts
  • Location: Hubley, Nova Scotia - Canada

Posted October 22, 2012 - 10:32 AM

Just a thought- Are you sure that it is running lean and doesn't have an ignition problem. I've found that sometimes an ignition problem can act like a fuel issue. A weak spark could cause rough running at idle. You could also try to get another used carb through one of our sponsors.

#8 Bigfoot OFFLINE  

Bigfoot
  • Member
  • Member No: 11780
  • 20 Thanks
  • 41 posts
  • Location: Ohio

Posted October 22, 2012 - 10:36 AM

What about a good strong dose of Seafoam in the gas and some light work.


Yes I've done that, I poured a whole bottle of that in the tank, a couple of weeks ago. Haven't run it much as of yet though.
Thanks

#9 HDWildBill OFFLINE  

HDWildBill

    Freedom is not Free. Thank those in uniform for your freedom.

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 6354
  • 8,702 Thanks
  • 8,557 posts
  • Location: Ga

Posted October 22, 2012 - 10:55 AM

Did you pull your Welch plug's? I had one a while back that would surge and not idle unless you choked it. Pulled the welch plug and there was all kinds of crap behind there. Also pouring a whole bottle of seafoam in the tank does no good unless you run the engine and let it run through the carburetor.

#10 Bigfoot OFFLINE  

Bigfoot
  • Member
  • Member No: 11780
  • 20 Thanks
  • 41 posts
  • Location: Ohio

Posted October 22, 2012 - 03:27 PM

Did you pull your Welch plug's? I had one a while back that would surge and not idle unless you choked it. Pulled the welch plug and there was all kinds of crap behind there. Also pouring a whole bottle of seafoam in the tank does no good unless you run the engine and let it run through the carburetor.


What is a Welch plug? Where on the carb is it located? Maybe a photo would make it clear.. Thanks

#11 HDWildBill OFFLINE  

HDWildBill

    Freedom is not Free. Thank those in uniform for your freedom.

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 6354
  • 8,702 Thanks
  • 8,557 posts
  • Location: Ga

Posted October 22, 2012 - 04:09 PM

What is a Welch plug? Where on the carb is it located? Maybe a photo would make it clear.. Thanks


I guess that answers my question. A Welch plug is a round disc that looks like this,

welchplug.jpg

They are found in the float bowl and also on the Carburetor body. Here is a pic of one installed in the top of a float bowl.

Welch_plug_installed.jpg

There is usually a slot or in this case an opening you can get a hook under it and pull it out. It is just press fitted in. You will need to have a replacement. Once it is out or if you know the size you can go to your local shop and they will usually have extra's laying around. My shop just gives them to me but I do buy most of my parts from them.

Once you have everything clean you just put the plug in the hole and I take a small punch and give it a couple of good hit's along the sides. Then I use clear nail polish to seal it but don't plug the passage. I suspect once you clean out behind the welch plug you idle problem will go away.

#12 Bigfoot OFFLINE  

Bigfoot
  • Member
  • Member No: 11780
  • 20 Thanks
  • 41 posts
  • Location: Ohio

Posted October 22, 2012 - 06:06 PM

I guess that answers my question. A Welch plug is a round disc that looks like this,

welchplug.jpg

They are found in the float bowl and also on the Carburetor body. Here is a pic of one installed in the top of a float bowl.

Welch_plug_installed.jpg

There is usually a slot or in this case an opening you can get a hook under it and pull it out. It is just press fitted in. You will need to have a replacement. Once it is out or if you know the size you can go to your local shop and they will usually have extra's laying around. My shop just gives them to me but I do buy most of my parts from them.

Once you have everything clean you just put the plug in the hole and I take a small punch and give it a couple of good hit's along the sides. Then I use clear nail polish to seal it but don't plug the passage. I suspect once you clean out behind the welch plug you idle problem will go away.


Well I guess I'm never to old to learn something new! I'm not sure about thes newer 318 carb, which is what I have, but I'll poke around it to see what and where these plugs are, and check them out. This gives me new hope. One thing I forgot to include was a spring assited diapham under a cone shaped cover on the side of the carb. I did remove the diapham and spring, and I noticed the rubber diaphram was stiff and kind of hardened some. I don't know what it was for, except maybe to compensate for air pressure or the like. with the engine running I losened the 3 scews a tiny bit and the engine soothed out at idle, however it blew black smoke at hight rpm's, so what does this prove? I don't know yet.
Thanks alot. Bigfoot

#13 HDWildBill OFFLINE  

HDWildBill

    Freedom is not Free. Thank those in uniform for your freedom.

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 6354
  • 8,702 Thanks
  • 8,557 posts
  • Location: Ga

Posted October 22, 2012 - 07:51 PM

You are never to old to learn new things. I learn quite a bit everyday by reading the post's on this site.

I'm not familiar with the 318 carburetor but the diaphragm apparently compensates fuel for different atmospheric conditions. When you loosened the screws you allowed more fuel to pass so Idle smoothed out but it didn't like the additional fuel at higher RPM. The diaphram should be flexiable, no cut's, and in overall good condition. If your's is hard the I think I would invest in a rebuild kit for the carburetor and that should give you everything you need including a new diaphragm welch plugs gaskets and o-rings.
  • MH81 said thank you

#14 TerryD OFFLINE  

TerryD

    Member

  • Senior Member
  • -GTt Supporter-
  • Member No: 5916
  • 132 Thanks
  • 254 posts
  • Location: Missouri

Posted October 22, 2012 - 10:45 PM

I had the same problem with an old 5 hp Briggs even after replacing seals and running Seafoam through it. Got frustrated and pulled the jets out and blew air into them with my rubber tipped blow gun and air compressor. Perfect now.

Watch out for any gas droplets that may blow up through the carb and get in your eyes.

#15 Alc ONLINE  

Alc

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 1094
  • 5,450 Thanks
  • 6,618 posts
  • Location: Bangor Pa

Posted October 23, 2012 - 05:54 AM

Not sure if this would help or not but I bought some off brand carb cleaner once and it didn't clean worth a darn . Went back over with Gumout and cleaned off varnish the other didn't even touch , might make a differnce in those passages if you try cleaning it again, Al
  • LilysDad said thank you




Top