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| Posted: Wed Sep 16th, 2020 07:46 pm |
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1st Post |
Eric Holt
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I am new to karting and new to your great forum. I will be as concise as possible.
I am having trouble with my Tilloston HL334A carburetor in that I can not achieve an idle on my WB820 engine.
Thus far I have cleaned the carb in an ultrasonic cleaner using hot water and a few ounces of Simple Green for an hour. I then was very careful to assemble in the correct order using a genuine Tillotson RK-117HL parts kit. The needle valve lever is currently set dead even with the carb body. (I tried both slightly above and below to no avail).I was sure to be certain the needle valve tips are clean and bright. The needles are set to: L-3/4 to 1 turn open. H-1-1/4 to 1-1/2 open. Changing these makes no difference.
The pop-off pressure is 9 PSI, and it holds pressure at 7 PSI. With the use of carb cleaner, I have confirmed that all ports are open. With the H, and L screws removed I can see fluid spraying through primary, secondary, and main fuel discharge ports. Just how well these are spraying is difficult to tell as seeing down in there is difficult.
This engine starts and runs easily but refuses to idle on its own. Installed is a new NGK spark plug. When I hold open the throttle plate I can see fuel spraying from the primary idle fuel discharge port, but in my opinion it appears to be a poor stream and a low volume.
Thanks for any responses that you may offer. I know there is a solution to my problem but I am stumped! Thanks a million to all.
Eric
Attachment: GK1200.JPG (Downloaded 314 times)
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| Posted: Thu Sep 17th, 2020 02:58 pm |
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2nd Post |
Terry Armstrong
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Hi Eric,
Welcome to the wonderful world of Vintage karting! Others may chime in and offer suggestions as well. I don't have experience with the West Bend 820, but with Mac's, Komet's, DAP's, etc.
You didn't mention whether the fuel was Gas or Alcohol? I've found Alcohol to be more finicky as far as idling is concerned. Also the condition of the engine: condition of seals, rings, etc. Also does the engine hold pressure if you seal it up and put 8 - 10 psi thru the intake or exhaust port?
A couple things you should check:1. Pulse Hole; make sure it is open with no restrictions between carburetor, gasket and intake manifold all the way down to the reed cage. I have had problems with this in the past! A poor pulse signal will cause erratic running.
2. Reed Cage; Make sure all gaskets are lined up correctly with the intake, reed cage and engine block. I recently installed a gasket incorrectly and the engine would only run at 1/4 throttle or more.3. Reeds: Make sure they are in good shape and making a good seal to the reed cage! Hold the reed cage up to the light and look from the opposite side to see if you can see light. If they don't lay flat against the reed block, the engine will run erratically.
Check back when you figure it out and let us know what you found!
Terry
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| Posted: Sat Sep 19th, 2020 01:45 pm |
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3rd Post |
Eric Holt
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Hello Terry,
Thanks for the warm welcome! When I was seven years of age in 1962 my neighbor took me for a ride around the block on his GK1200. Being too young at the time I have dreamed of one day owning a GK1200; that day has arrived.
I am burning 91 octane without ethanol gas with castor oil. I never thought that I would need to learn so much more about the two-stroke motors but I guess this comes with the sport. I will make up some blocking plates with a hose barb in order to see if this will hold 8-10 PSI.
I will also learn all about the pulse hole and reed cage topics. Thanks a million for taking your time in trying to help me out; I sure appreciate that! I will surely get back as I progress in this adventure...I really hoped to get to a track in the northeast this summer or fall but that does not look feasible now.
Eric
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| Posted: Sun Sep 20th, 2020 08:05 am |
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4th Post |
steveohara
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Eric,
You did not mention the idle control screw setting in your description of the prep you did to the carb. For that carb, the correct setting for most engines is arrived at by backing the control screw off until it no longer makes contact with the lever on the end of the throttle shaft. Once it is not touching the butterfly seal should be checked to assure the butterfly is not offset. It should fit the bore very close to a perfect seal. If it appears offset... you can see light on one side but not the opposite side.... loosen the butterfly screw and adjust the position to allow it to close completely. With the butterfly centered, turn the idle control screw in until it just makes contact with the lever and then continue turning it one more full turn. Set both mixture screws to 1 turn and fire the engine and warm it up for 60 seconds by opening and closing the throttle quickly in very short but wide open applications. Do not use part throttle to warm it up.... open, close, open, close... keep revs in the 2 to 5K range with no load on the motor ( axle spinning). Once it is warmed up, hold the brake and apply full throttle for three seconds and then let off the brake and throttle together. Have a small screw driver ready to adjust the idle control screw to get it to the desired idle speed.
Do this routine after you have completed all the inspections Terry outlined above to make sure you are not dealing with an air leak, pulse passage restriction or leaking reed valves.
Good luck.
Steve O'Hara
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| Posted: Sun Sep 20th, 2020 02:13 pm |
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5th Post |
Eric Holt
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Hi Steve,
And thanks ever so much for your reply! I did adjust the basic throttle butterfly setting as described by Tillotson. However, your additional insight is the kind of stuff never found in books. I will be sure to verify that the butterfly is centered and forming a complete seal. Your warmup procedure is all new to me...thanks for that! I will work on checking for air leak, pulse passage restriction, or leaking reed valves; this is all new territory for me. I will be sure to print all of these posts to have among my literature.
Thanks again...
I certainly have some work to do!
Eric
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| Posted: Wed Sep 23rd, 2020 03:30 pm |
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6th Post |
Mike Berg
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Just a suggestion.
My experience with ethanol gas in 2 strokes is not good, the ethanol will swell the inlet needle or seat depending on which type you have, this lowers the fulcrum arm severly limiting the amount of fuel your carb can pass. reset the top of your fulcrum so it is just the thickness of the fulcrum above the floor of the casting. Do not use ethanol fuel. Good Luck.
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| Posted: Fri Sep 25th, 2020 07:44 pm |
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7th Post |
Eric Holt
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Hi Mike,
Thanks so much for your input on my post! I never use gas with ethanol in any of my two-stroke engines; I do recognize just how harmful this stuff is. See my Sept 19 post, I am using 91 octane ethanol-free only.
I really like your input on the fulcrum arm..."reset the top of your fulcrum so it is just the thickness of the fulcrum above the floor of the casting." This is more good information never found in books but only learned from others.
All the best,
Eric
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| Posted: Tue Sep 29th, 2020 11:27 pm |
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8th Post |
S Kneisel
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Hi Eric,Welcome aboard.Lots of good advice here from some experienced guys.
I do have one question though.....When you cleaned the carb did you remove the welch plug closest to the mounting flange?
If not you might want to remove that plug by drilling a small hole in the plug being careful not to plunge the drill too far once you break thru. I drill until the bit sust starts to break thru the bottom surface of the plug. Then pry the plug out with a sharp awl.
Look at the 3 or 4 holes below the plug, shine a light in the carb and you should see light thru all of the small jet holes. The hole closest to the carb flange is the idle jet. This is what supplies fuel when the shudder is closed. If this is plugged or partly plugged the engine will not idle properly or not at all.
Maybe you checked this but in case you did not, I suggest you check this jet.You should have got a new welch plug in the rebuild kit, if not you can get them from EC carburetors.
My 2 cents
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| Posted: Sun Oct 4th, 2020 02:43 am |
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9th Post |
Doug Tenney
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When it's working correctly, a US 820 with a single Tillotson HL is a very stable, forgiving combination.
Sorry if you mentioned already, but as Terry said, you need to verify that the pulse passageway is open all the way from the underside of the reeds to the carb flange. The carb flange gasket will fit onto the studs 4 different ways, but only one is correct.
When you pressure test the the crankcase, IMHO going up to 5 psi will be plenty. Turn off the air (or stop pumping) and see how well the pressure holds on your gauge. The seal on the crankshaft PTO can pop out of its bore, and if it's covered by the clutch, you may not see it.
After reassembling the carb, when you crank the engine, before it fires, you should see the fuel progressing smartly up toward the carb (assuming tubing transparent). If you don't, then the pump isn't working.
Suggestions for pressure testing:- Replace the spark plug with a hose barb fitting that you buy or make up.
- Use thin sheetmetal to construct a block off plate for the exhaust The metal does not have to be thick as long as you sandwich it between the muffler/header flange and the block.
- Repeat for the intake side. Sandwich the plate between the carb flange and the reedblock.
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Eric Holt
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Hello S. Kneisel and Mr. Doug T.
It is with such appreciation that you both and all the others that have reached out to help me in this forum. This is the next best thing to having you guys at my side offering what is priceless, and experienced help!
No, I did not drill and remove that welch plug. In other Tillotson carbs I understand there is a one-way valve in there, but I don't think there is one in my carb. With that plug removed It sounds like I can really see if these passages are open. I will do this process and have a look in there.
I made this kill button box last winter. The engine did idle long enough to use this one time...
I had a local man by the name of the late Dave Kneisel that was quite a dirt track racer...
I fully intend to print all of these posts and keep them with my gear. It will be a while till I get to testing given all of the many things going on these days. I will and do plan on getting back with my results and more than likely I will have questions, as this is new territory for me.
A million thanks! EricAttachment: IMG_4780.JPG (Downloaded 169 times) Last edited on Mon Oct 5th, 2020 08:19 pm by Eric Holt
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Eric Holt
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Thanks ever so much Doug!
I have been to their site many times but never saw these links to overhaul the HL.
I am one that can never have too much information.
My experience with two-stroke carbs is limited to ultrasonic cleaning, new parts kits and away I would go. Getting my Tillotson and WB820 working as it should represents a lot of learning for me.
Eric
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Eric Holt
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Hi Doug,
Okay, It is becoming clear how you block of the intake, and exhaust for pressure testing.
This apparently is done, leaving the carb and muffler in place, with sheet metal sandwiched between the muffler, or carb areas, I assume with a gasket on each side of the sheet metal in order to form an air-tight seal.
I will somehow make a fitting to thread into the spark plug hole that will accept my pop-off tool, which I can then apply about 5 PSI.
I will also find a piece of clear 1/4" fuel line in order to monitor fuel flow during start-up.
I will inspect the carb flange gasket too, also new territory for me. Also the pulse passageway, new to me too; I will study this topic online.
I will report back,
Eric
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| Posted: Mon Oct 12th, 2020 07:49 am |
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14th Post |
Doug Tenney
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Hi Eric.I bought my spark plug-hole-air-fitting from Greenzweig's Kart Shop in PA.
I made the gaskets from soft sheet rubber from Azusa Engineering. If you're not familiar with them, you NEED to check out their catalog. Very reasonable prices, strictly "old school," sell only through kart shops.
Be very tender removing the welch plug. Very easy to ruin the carb. It's all explained in that documentation. Also follow the process for setting the new one.
Finally, if none of this helps, you may need to just try a different HL. They've been making them for nearly 60 years, so they're out there. (Way too stubborn here, I need to follow my own advice.)
Doug
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| Posted: Mon Oct 12th, 2020 08:06 pm |
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15th Post |
Eric Holt
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Thanks a lot Doug,
I dug out an old cylinder leak-down tool that I made some 35 years ago; this should do the trick. Thanks for the rubber sheet idea...very good.
I do understand how extreme care must be taken while removing the welch plug, setting the new one is also crucial.
Good laugh...I would like to make my HL work. New ones are quite expensive, used ones are a gamble I guess.
Living in the northeast PA area I hope to try my kart in Oreville PA one day in the spring.
Hope to add a pic of the tool I made. Many thanks, EricAttachment: Leakdown Tester.JPG (Downloaded 123 times) Last edited on Mon Oct 12th, 2020 08:07 pm by Eric Holt
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| Posted: Mon Oct 19th, 2020 04:18 am |
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16th Post |
| Posted: Mon Oct 19th, 2020 09:28 pm |
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17th Post |
Eric Holt
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Hi Doug, That is one heck of an offer! Perhaps one that I can't refuse! If the weather looks good for that day I will likely take you up on that. Thanks a million! Eric
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| Posted: Sun Mar 14th, 2021 05:48 pm |
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18th Post |
Eric
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March 14, 2021
To all that came to my aid VIA the Vintage Karting site: Terry, Steve, Mike, S Kneisel, and Doug.
Your many wonderful pointers, thoughts, and suggestions were greatly appreciated, and have served to make me a whole lot smarter than when I began. I have had positive results with my WB820, which I will share last.
I will reply to each suggestion with the results of my study; perhaps this may be of help to others.
Per Mike: I’ve always stayed away from ethanol gas, and love the suggestion to “set the fulcrum arm so it is just the thickness of the fulcrum lever above the floor of the casting.” This has now been done…
Per S Kneisel: “Did I remove the welch plug?” When I cleaned the carb in ultrasonic cleaner (hot water with 2-oz Simple Green 45 minutes) I had not removed the welch plug. Since then, to verify, I have now carefully removed that plug to easily see that all 3 small jet holes are as clean as a whistle! That has now been checked.
Per Terry & Doug: Terry asked if I was “burning gas or alcohol?” I am burning 91 octane ethanol-free gasoline. Terry and Doug also asked about the “condition of the engine: seals, rings etc.”
* I blocked off the intake and exhaust ports, applied 8 PSI into combustion chamber via spark plug hole. This easily maintained this pressure.
* I then blocked off the intake and applied 6 PSI to the exhaust port which also held without signs of concern.
“Pulse Hole?” This is new territory to me but I did my best to assure this these passage ways were all okay.
“Reed Cage?” I verified that intake manifold, reed cage, gasket, and block all were in their correct positions. Please see added images.
Per Doug: Doug writes, “when you crank the engine, before it fires, you should see fuel progressing smartly up toward the carb.” With yellow fuel line in place, spark plug removed, socket/ratchet on clutch I then spun the engine. With each revolution I was able to see fuel pulsing smartly towards the carburetor; this was significant.
Per Steve: Steve states: “the butterfly seal should be checked to assure the butterfly is not offset.” Fortunately for me, the butterfly was perfectly centered, and formed a perfect seal…no light passed through. I then turned the idle control screw one full turn beyond where it just made contact.
With both carb adjustment screws set to 1-turn open, and 1-quart of fresh 91 octane, ethy-free gas mixed with castor oil I was all set to give this another try.
Armed with a new warm up procedure per Steve the engine fired well. I warmed up 1-minute using short but wide open throttle bursts…open-close-open-close.
I did hold the brake and throttle for three seconds but the engine still wanted to stall…that is until I moved the idle control screw open per Steve and yippee, the engine idles! With snow all melted I was able to take a few victory laps around on our very level lawn area.
My final comments: I needed to go through a lengthy checklist to be certain of just what I was dealing with. I believe the major culprit was two-fold, I did not know of a proper warm up procedure, and having read of the proper setting of the idle control screw, 1-turn beyond fully closed, I just went brain-dead and left that setting alone. There just was not enough air available for this WB820 to idle. Thanks Steve for triggering my brain to “adjust the idle control screw to get the desired idle speed.”
I now look forward to this summer and doing something I have dreamed of since the summer of 1962, sitting behind the wheel of a GoKart 1200. Eric HoltAttachment: Kart Int Gask hole align.JPG (Downloaded 48 times) Last edited on Sun Mar 14th, 2021 06:00 pm by Eric
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