How to adjust Idle Screw that does nothing? Lefty-Loosey & Check Throttle! Honda FourTrax 300 Carb

[@garmbeliblis]

Outstanding explanation and presentation. My quad is not idling out anymore and I'm a smarter human.

[@chainsawchips]

I like your "make shift gas tank".🙂

[@blakereifsteck8460]

Dude your video absolutely saves my ass and is well said. 👏

[@DaveNorthWest]

Always just leave the throttle with max slack then when "Cold" adjust the carbs idol to barley running. When "Warm" adjust the barrel adjuster at the thumb throttle. Also make the adjustment with the bars point to the left as far as possible because when steering to the left it puts tension on the cable unless you have the cable perfectly routed like it should be

[@alexoxley2619]

This helped me so much!!!

[@baileyhall3510]

Why would my 1988 Honda trx 200sx instantly shoot in full rev when it’s fire up? I just got it today and I’m trying to figure it out. I’m ordering a new carb, intake manifold and throttle cable bc I feel like there might be an air leak. But I just wanna make sure thats what it could be.

[@JaredP-d8s]

You saved me a lot of frustration! Thank you!

[@nathangood1273]

Huge help thanks !!

[@peytonmorgan32]

So I replaced my carburetor on my Honda 300 it runs completely normal in neutral. I can rev it all the way out and it will not cut off and it will run all day. But as soon as I shift it into gear and give it about half throttle it tries to bog out, but it doesn’t fully, I’ve tried adjust the pilot screw, and throttle, but it still does it. Do you know why this might be?

[@AJsShop]

Here in Utah it's desert and the temperature swing pretty wildly - it can be 30s or 40s in the morning in the shade and 80s or 90s in the sun. I have that problem frequently and it's typically the choke not being adjusted properly for the current conditions. I'd say check that your choke isn't stuck. I'm just a hobbyist and not too knowledgeable about all of this though - so take it with a grain of salt.

[@peytonmorgan32]

@@AJsShop Ok thanks for replying. My choke switch is broken but it use to run even when it was broken. I’ll look into it further

[@junkyardfishing1349]

I have a silly question if you have a min. I replaced a carb on one of these with the same one you have in this vid. I noticed that nothing moves the plunger and needle only the butterfly. is it something that runs on vacuum? the kit did not come with directions of course and I'm trying to not mess it up during install. I bought it from a guy who put a brand new carb on it but it was for a 250 x ( yellow manual choke) but that one moves the plunger and needle with the throttle cable as well as the butterfly valve. I have experience with small engines however, I am new to atv's and couldn't pass up the deal. if you are able to set me in the right direction, I would greatly appreciate it. its a 1987 trx250 2x4 that I am working on. thanks in advance

[@AJsShop]

I'm just an amateur myself, so I'm not really sure, but what I think of as the "plunger" requires gas in the well to operate. I can't remember what was controlled by the choke. Definitely check out @SmarterEveryDay's video on carbs (kzbin.info/www/bejne/qqC5l6mInbyVoJo) and cross reference that with a browse through the various diagrams on the Wikipedia article on carburetors (en.wikipedia.org/wiki/Carburetor).

[@fourbyfourer]

If I am understanding you correctly, the carburetor you are talking about has the throttle cable attached to the top of the carb by screwing on a cap and the throttle cable operates the slide up and down. In this video it is a vacuum operated diaphragm slide. You were correct when you said it moves up and down due to vacuum.

[@sonoma456]

thank you and it did help

[@ericpowell8836]

So I di this and it runs perfectly brand new carb but if I drive it it seems like it's not getting enough gas do I need to adjust the air/gas screw?

[@ericpowell8836]

It's a brand new carb I really don't feel like I need new jets but it seems that way

[@AJsShop]

If you push the throttle wide open, does it get enough gas then? Or how about if you turn the choke on 1/4, 1/2, 3/4, full? Does any of that make a difference better or worse? If the throttle helps, you may want to loosen the screw another quarter or half turn for a richer mixture. If the choke helps you may want to tighten it for a leaner mixture. Fair warning: I'm a total amateur, so I really don't know. I'm just taking educated guesses.

[@ericpowell8836]

@@AJsShop so I did the choke all kinds of ways it don't run any better while moving but if I hit full throttle it don't bog down in nuetural or drive .when in drive it want bog down pr anything it just dies like i can haul tale for like 10 seconds lol I appreciate it. On mine it has a filter from the gas tank to the carb I don't think there enough gas draining into that filter reckon ima blow that line out

[@shawnmcclure7282]

Also gotta adjust air fuel ratio til comes up on faster idle then back off fine tune then manually idle down with screw your talking about

[@Reaper-td7nf]

How do you adjust the jet under the carb . I can’t get to it to turn it, what do you use to adjust it. I can barely get my hand under it. It’s a little harder when you are in a wheelchair. Any help will be appreciated.

[@Reaper-td7nf]

@@RimfireGoblin I think I used the wrong term when I said jet, it’s the fuel air ‘screw’ under the carb. I think you said to fine tune the idle. It has the rubber boot on it. I had no idea about the adjustment on the throttle I thought you just set the idle screw on the carb. I’d still be twisting on that thing doing nothing if I hadn’t watch your video it was a great help. Thanks for that. But the fuel air screw is a different animal to get to. Thanks for what you do.

[@AJsShop]

Check out the "Pilot Screw Adjusting Tool" by "Motion Pro". That should help you out. You can get it on Amazon, but if you think you'll be doing work semi-regularly, go through Rocky Mountain ATV instead - hey have everything, and you can also call them on the phone if compatibility is ever unclear on the website, and they have tons of great tips videos on KZbin. (or there's another place called Dennis Kirk that sometimes has a different selection of parts and tools)

[@bobmederos270]

Does your choke also increases idle at start, and if it doesn't is there a problem with the choke?

[@AJsShop]

When the air is freezing cold, it's more dense. The choke cuts off airflow so that the gas mixture is higher compared to the cold air. If it's not cold enough when you use the choke then the mixture will be too high and it'll die, starved for air. If it's very cold and you use the choke it will idle higher, because without it it's starved for gas. That's my understanding. It's freezing outside right now, so I have to put the choke on to get mine started.

[@DanKelley08]

How do you adjust the idle while its running without burning your hand?

[@AJsShop]

1) Start it cold. 2) Wear gloves.

[@ImCalvinr93]

I got to keep my grandfather’s grizzly 660 and have an idle twist screw that bends and wraps around.

[@AJsShop]

Tusk Tach/Hour tachometer video: kzbin.info/www/bejne/fp2TkH-eet6ZnLM