vanagon40
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« on: May 31, 2022, 10:40:35 AM » |
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It's an 8 HP Briggs & Stratton on a Troy Bilt tiller. It ran like a top until this morning. To me, it acts like it is starved for fuel. Fuel flow to the carb is fine. Spark plug looks good. This is not my area of expertise. First video starts at idle and then wide open throttle. Second video is all wide open throttle. This morning, it was running great for twenty foot through the garden and then bogged down like it was out of gas. Restarted and made it only another foot. EDIT: Forgot to add that air filter looks fine. Any ideas? https://youtube.com/shorts/iTdp3uvjf4Mhttps://youtube.com/shorts/MkQsi2S0iIcUPDATE: Cleaned the small holes on the carburetor nozzle and adjusted the high speed valve. Problem solved and runs great. See details Here
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« Last Edit: June 19, 2022, 11:23:08 AM by vanagon40 »
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f6john
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Posts: 9380
Christ first and always
Richmond, Kentucky
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« Reply #1 on: May 31, 2022, 10:43:20 AM » |
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Depending on age I would suspect a bad diaphragm in the carb. Make sure no water has gotten into the gas tank also.
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vanagon40
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« Reply #2 on: May 31, 2022, 11:10:27 AM » |
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Age = really old (i.e., 1978 or 1979)
Gas is fresh (and I completely emptied the tank once this spring).
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Patrick
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Posts: 15433
VRCC 4474
Largo Florida
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« Reply #3 on: May 31, 2022, 12:37:30 PM » |
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Will it sit and idle when the throttle is back ?
Have you tried adjusting the carburetor ? There may be both low/idle and high speed adjustments. The high speed is in both video's near the bottom of the carb. in is lean, out is rich. Try turning the screw out about 1/8 turn. Try it see what happens. Try another 1/8 turn out see what happens. Thats a float carburetor and it seems like there may be some junk [ technical term] in the float needle valve which is kinda common. Access to the float is by removing the float chamber [ the thingy that the needle valve is mounted to. Generally that can be removed and looked without removing the carburetor. Try to be careful not to ruin the gasket.
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OnaWingandaPrayer
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« Reply #4 on: May 31, 2022, 02:55:22 PM » |
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No diaphram on that carb. I would take the high speed jet (coming at an angle from the bottom of carb ) out and let it drain to see if any trash is there. Also note if the flow is steady(perhaps the supply line has an issue). Install the jet back in place start engine and make high speed jet adjustments. From the sound and lack of black smoke I would turn CCW and see if that helps . It does seem to be starving.
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Robert
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« Reply #5 on: May 31, 2022, 03:32:07 PM » |
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Fuel, check the jets maybe clogged or it looks like it has a high speed jet open it up and see if it keeps running. Sometimes when those engines get warm and there is a fuel blockage they will die.
Check oil level also, I see a regulator that has something to do with oil coming out next to the filler hole. Taken those apart before and just dont remember what those did but it was something to do with oil.
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« Last Edit: May 31, 2022, 03:36:39 PM by Robert »
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“Some people see things that are and ask, Why? Some people dream of things that never were and ask, Why not? Some people have to go to work and don’t have time for all that.”
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signart
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« Reply #6 on: May 31, 2022, 03:37:11 PM » |
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As O W P suggest, drain the carb into a glass jar and look not only for trash, but water in the bowl.
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Oldfishguy
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« Reply #7 on: May 31, 2022, 04:56:38 PM » |
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Start simple. Replace the plug. A bad plug has fooled many a mechanic in to hours of needless carb work.
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old2soon
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« Reply #8 on: May 31, 2022, 05:18:15 PM » |
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Start simple. Replace the plug. A bad plug has fooled many a mechanic in to hours of needless carb work.
and the plug wire and plug cap. that plug wire catches a LOT of heat. RIDE SAFE.
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Today is the tommorow you worried about yesterday. If at first you don't succeed screw it-save it for nite check. 1964 1968 U S Navy. Two cruises off Nam. VRCCDS0240 2012 GL1800 Gold Wing Motor Trike conversion
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Bigwolf
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« Reply #9 on: May 31, 2022, 08:44:17 PM » |
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I have an 8 horse Briggs on a chipper/shredder that was giving me trouble. That on/off switch is a cheap piece of crap that was coming apart on mine! I replaced that switch with a good toggle switch and it now runs fine. Check it out. I don’t think fuel is your problem, I think it is electrical. It’s been a while, but I think that is the way mine was running before I replaced that switch.
Bigwolf
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oldsmokey
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« Reply #10 on: June 01, 2022, 01:42:38 AM » |
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As mentioned above, fuel getting to the carb. Is one thing, properly metering through it is another. Have you attempted to gradually close of choke to compensate for lean condition?
If you remove the high speed needle and seat there will be a long brass main nozzle inside that. It is threaded through the two halves of carb. A good hollow ground srew driver will remove it. ( note, must be removed before any attempt to separate halves)
You may find some debris there if it is a fuel issue
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Patrick
Member
    
Posts: 15433
VRCC 4474
Largo Florida
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« Reply #11 on: June 01, 2022, 03:47:54 AM » |
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I have an 8 horse Briggs on a chipper/shredder that was giving me trouble. That on/off switch is a cheap piece of crap that was coming apart on mine! I replaced that switch with a good toggle switch and it now runs fine. Check it out. I don’t think fuel is your problem, I think it is electrical. It’s been a while, but I think that is the way mine was running before I replaced that switch.
Bigwolf
Thats a good point.
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Patrick
Member
    
Posts: 15433
VRCC 4474
Largo Florida
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« Reply #12 on: June 01, 2022, 03:49:32 AM » |
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I have a Troy-built. At the angle they run at the high speed adjustment can be finicky and the needle needs to be tweaked at times.
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vanagon40
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« Reply #13 on: June 01, 2022, 04:57:59 AM » |
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Thanks for all the suggestions. I will be out of town the rest of this week, so this project will have to wait until next week. I will post the progress and/or results.
Thanks again.
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Robert
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« Reply #14 on: June 01, 2022, 05:46:43 AM » |
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Thanks for all the suggestions. I will be out of town the rest of this week, so this project will have to wait until next week. I will post the progress and/or results.
Thanks again.
Kill Joy, does not satisfy the needs of the immediate gratification crowd, LOL.
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“Some people see things that are and ask, Why? Some people dream of things that never were and ask, Why not? Some people have to go to work and don’t have time for all that.”
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indybobm
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« Reply #15 on: June 01, 2022, 06:53:47 AM » |
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I am assuming that you putting E10 gas in it. I would add a high dose of Chemtool B12 in the tank and run it while varying the throttle. I treat all of my gas with Lucas Ethanol Fuel Treatment, about an ounce to each five gallons of fuel. i usually add a little extra. i do this with each tank of gas on my Valkyrie and each of my gas cans. I had the same problem with my Mantis 4 cycle tiller. By the way, Chemtool B12 is about $4.00 at Walmart and the Lucas Ethanol Fuel Treatment is about $11. Lasts a long time.
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So many roads, so little time VRCC # 5258
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Patrick
Member
    
Posts: 15433
VRCC 4474
Largo Florida
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« Reply #16 on: June 01, 2022, 09:16:00 AM » |
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Thats a good point too. I only use non-ethanol in the small engines. That damn ethanol does raise He!! with float valves and jets.
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LTD
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« Reply #17 on: June 01, 2022, 02:37:13 PM » |
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change the air filter same symptoms changed it good to go
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vanagon40
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« Reply #18 on: June 19, 2022, 11:20:20 AM » |
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Finally made time work on the tiller (my wife wanted the garden tilled). I replaced the spark plug and there was no change. I removed and disassembled the carburetor. I was amazed at how clean it was inside.   The only problem I could find was one or two of the pin holes on the carburetor nozzle were plugged.  Cleared that and reassembled the carburetor. There was improvement in wide open throttle, but still stalled out under load. A slight adjustment of the high speed valve cured the problem.  I am good to go. Thanks for all the suggestions and advice.
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da prez
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« Reply #19 on: June 19, 2022, 07:33:12 PM » |
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I tell all my small engine customers to use mid-grade fuel with marine stabil added. Summer for lawn mowers and winter for snowblowers. It also takes care of storage problems.
da prez
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Patrick
Member
    
Posts: 15433
VRCC 4474
Largo Florida
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« Reply #20 on: June 20, 2022, 06:26:38 AM » |
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Good, easy fix. I like easy,
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Jess from VA
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« Reply #21 on: June 20, 2022, 06:38:03 AM » |
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I thank my stars that there is a top notch lawnmower (and all small engine) shop (Stihl dealer) that has been in business for some 40 years, that services nearly all the hundreds of local lawn and tree businesses, about a mile from my house. I do my best to maintain my various small engines and equipment, but that is never good enough. They get all my business and new purchases, even though I can beat their higher equipment prices at the big box stores.
There may be 75 lawnmowers (and other) ahead of me, so I shoot to get work done in wintertime, if I get that lucky. Same exact deal with my good Valk mechanic, an hour away.
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