Rebuilding 8N carb-tips & Tricks????

6381 Views 15 Replies 5 Participants Last post by Dollar Bill, Oct 9, 2013

TAHOE99

Discussion Starter · Sep 11, 2013

I'm helping a friend get a '52 8N running, fuel system is a mess. I have all parts off tractor, tank will get a an acid etching and cleaning to remove rust/varnish. The bowl has goop in it that I got to get out if I can get bowl off, haven't taken carb apart yet.

I have printed off a few rebuild instructions from a couple of peoples' websites, just wondering if anything I need to look at for as I take it apart. i.e. tips or tricks.
I hope to get rebuild kit at TSC or maybe NAPA.

Also, the rubber hose connections between the steel tube and air cleaner and carb are rotted, any suggestions? I saw rubber connection joints in plumbing section, thought they may work. Guy isn't spending a lot of money, jsut needs to get running for winter snow removal.

Thanks!!! :fing32:

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JohnW

· #2 · Sep 11, 2013

Get some Berryman's to soak the carb in, after an hour or two the carb will look like new. I like to take a set of torch cleaning tips to make sure the passages are clean plus a good air compressor to blow them out. If the kit comes with the rubber tipped float valve then keep the old brass one that I hope is still in there.

Also be careful not to get the jets reversed, they can be put in either hole and that can really mess up your day when you go to set the carb.

The rubber hose connections are just straight radiator hose nothing special about them.

MOA1

· #3 · Sep 12, 2013

Best thing you can do is put a filter on the fuel line. I cut mine with a tubing cutter and installed automotive fuel filter. Once you have it clean, keep it clean or you'll be doing it again. Soon. I'm not worried about the fuel tank as long as it will let gas thru. The filter takes care of the rest. Get a clear one. Good luck. If it runs good after rebuild you are all set. If not, check valve clearance, matter of fact, might as well do that when you have the carb off, just do it and be sure.

SonnyT

· #4 · Sep 12, 2013

Check the N stickies for info on the 3 factory fuel filters so you don't forget one.

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TAHOE99

Discussion Starter · #5 · Sep 12, 2013

Thanks all.

I finally got bowl off the sediment bowl assembly, looks like bowl maybe cracked and O ring is hard as a rock, can't get the screen out either as it's "welded" to the plastic, but didn't push it late last night either. May just buy a new assembly, I think they run about $20-25.
Dumped about a 1/2 cup of rust out of tank last night and still more in there. Need some bolts/nuts or chain and some mild acid too for more rust removal.

Thanks Sonny, I checked the FAQ's before starting a thread, I've seen 2 screens, haven't pulled carb apart to see the third. I am surprised they used just the screens and no inline filter, guess those worked well enough. I'll have to talk to owner, I would like to add another inline filter between bowl and carb, but up to him.

Not sure about the valve settings, we just need to get it running right now. It was a runner before he quit using it 3 yrs ago so hopefully just a fuel system rebuild will get it going again.
If it was mine, I would attempt to dig deeper if needed, but being someone else's, maybe little above my attempting.

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JohnW

· #6 · Sep 12, 2013

Do not add a filter in line, the 3 screens are all that is needed to properly maintain the fuel system. There have been issues with the filters starving the carb they were not designed for a gravity feed system.

TAHOE99

Discussion Starter · #7 · Sep 13, 2013

JohnW said:
Do not add a filter in line, the 3 screens are all that is needed to properly maintain the fuel system. There have been issues with the filters starving the carb they were not designed for a gravity feed system.

That's good to know, won't even need to mention it to owner! :fing32:

Anyone know if parts at Tractor Supply or Rural King are decent quality for rebuild? Looks like I can get all parts I need right off the shelf.

JohnW

· #8 · Sep 14, 2013

Most likely they are Tisco kits that almost EVERYONE have, not great kits but there are doable.

MOA1

· #9 · Sep 15, 2013

JohnW said:
Do not add a filter in line, the 3 screens are all that is needed to properly maintain the fuel system. There have been issues with the filters starving the carb they were not designed for a gravity feed system.

I've had no problem with the extra filter I put on mine. I paid attention to the inlet/exit size and went as big as I could with a decent size filter.

The metal screens just don't filter down to a small enough micron for my liking. Get to bouncing around and it stirs up all the sediment. Empty the carb bowl, then open the fuel valve too fast and it sends all the sediment down the system.

I like the additional filter, no problems with it. I installed it about 10 inches above the carb.

MOA1

· #10 · Sep 15, 2013

It is possible that the guys at the auto parts store were aware of the flow issue and pulled from a list of filters that would work. The local parts store is one of the best around, knowledgeable guys, they were aware of the application.

Or I just got lucky?

TAHOE99

Discussion Starter · #11 · Sep 23, 2013

I got carb all pulled apart, man what a rust bucket. I'm soaking it now to be able to turn choke enough to get screws out of the plate, it was stuck in open position.

Question, I cannot get idle jet to come out, the brass slot is wanting to chip off. Can I leave it and just use small wire and compressed air to get it cleaned out?

Also, the directions I was following says to remove the main jet where float needle goes and that there is another screwed in jet down in the hole.....I see nothing but a hole down there. Was I reading right, is there one down below?

Dollar Bill

· #12 · Sep 28, 2013

2

You've likely already finished this but for posterity, I would try to remove it, there's a cavity behind the jet that could hold debris and cause issues later on - Try soaking with either Kroil/PB and then hitting it with a butane torch. Be sure to use hollow ground or gunsmith's screwdrivers to avoid tearing out the slot on the jet.

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TAHOE99

Discussion Starter · #13 · Oct 8, 2013

Thanks Dollar Bill.

I had carb soaking for about 2 weeks, got most of it cleaned up. Finally was about to get the idle jet out, guess the soaking freed it up some.

Ran into a couple new problems,...the kit I got came with three new jets, but none fit into the "economiser" jet. They are either too big or just fall into hole. I cleaned up the old one as it came out easily, will have to reuse it.
I also found out there is a jet waaaayyyyy down in the main jet that needs to come out, can't even see the booger. I have no screwdrivers that will fit, guess I am going to have to break out a the grinder and make me one.

Oh, what seal goes on the throttle shaft? I have a cupped rubber seal and then I have a felt seal, Not sure what goes where.

Dollar Bill

· #14 · Oct 8, 2013

The carb kits that are now available fit a multitude of models so I'm not really surprised the jets are different sized - Soak the old ones and run a torch tip cleaner through them.

You could actually remove the economizer jet as it only serves as a vent.

This is what I have recorded for jet sizes for the 241B:
Idle Jet Minimum Size = 0.032, Max = 0.046
Economizer Jet Minimum Size = 0.046, Max = Whatever It's just a vent
Power Jet Minimum size = 0.043, Max = 0.053

The felt piece goes on the choke shaft. The spring for the choke return holds the felt piece in place. The throttle shaft takes the rubber cupped seal, and is held in place by a small brass cup.

TAHOE99

Discussion Starter · #15 · Oct 9, 2013

Dollar Bill said:
The felt piece goes on the choke shaft. The spring for the choke return holds the felt piece in place. The throttle shaft takes the rubber cupped seal, and is held in place by a small brass cup.

Ahh, yea there is what looks like a brass ring with some type of seal in a groove, but it's falling apart. Does that ring come out then?

Dollar Bill

· #16 · Oct 9, 2013

That's affirmative.

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