I dont think anybody out there can break down the circuitry the way you do. Nothing like being able to see in your minds eye whats going on. I have been able to troubleshoot so much better w all your teaching and circuitry breakdown. Just amazing.
Another excellent video which clearly explains the majority, if not all of the 'fuel starvation/choke on' problems encountered with small engines. The only fun left now is work out which one of these issues you are having? 👍
Had this problem with my small 2 stroke generator yesterday. Went through it after seeing this video, didn't actually see any issues, but after cleaning the system and tightening everything up, it now runs perfectly. Thanks for your help.
Thanks for the video! I had this problem, and after watching this video, I was able to pinpoint the problem. It was the metering diaphragm. It had become too stiff with time and it wasn't allowing the needle valve to come off its seat and allow sufficient fuel flow to the main jet after taking off the choke. Out of curiousity, I compared the new diaphragm to old diaphragm, and the new one was much more flexible.
Carburetors have always scared me because I never understood them. Until I have been watching your videos!🙂 Now I have more knowledge of carburetors and their workings!👍 Much thanks to you Sir!🙂
Great refresher for me. Used to race motorbikes forty years ago and had forgotten what I had forgotten if you know what I mean. Nice simple early 2 stroke tech, love it. Keep up the good work.
So very well done! Absolutely clear, concise and well shown. Couldn't imagine having it done any better. Cheers to an amazing job. Very much appreciated. Thank you!
Thank you for this great explanation. I was having a hard time figuring out what is going on with my two stroke outboard and this has helped me identify the problem and fix it. :)
I'm actually watching all of your applicable videos on two stroke engines because of my interest in flying 2 stroke engines on Paramotors. Not until today did I understand the low and high limit screws on my British made Parajet Maverick, that has an Italian 2 stroke engine made by Vittorazi. Oh by the way, your electrical explanation videos are great too.
Awesome Video.Everyone that works on engines should sit down and watch this.Thank's for sharing Your knowledge in a way that makes the whole fuel circuit easy to diagnose.
Excellence in action here, mate. Perfect presentation, clear explanation, perhaps showing actual examples of each component would help the inexperienced viewers even more. Not a criticism, encouraging the excellent work you have done.
Very good video. I have learnt alot. Thankyou very much. First time seeing 1 of your videos. And ofcourse I subscribed. Great job teaching us. Thankyou☺
all vids are great and very helpful. i did notice one lack or i missed seeing it. it is how a def hi ck valve preven ts purge bulb drawing in fuel and pushes out all fuel when in low speed. ck not closing on low circuit lets 14.7 lbs atmosphere pressure push into metering area pushing diaphragm away shutting off fuel supply and gradual starving down at low speed/idle and adding air to chamber and pushing all fuel out of purge bulb. with no ck /defective works good on hi speed and full choke starts ok 5-7 pulls like no purge bulb. engines. thanks for the great vids.
Thank you, you just made a small problem bigger. BUT in doing so you increased our understanding. Which I think is a good thing. You educate us and that is the best thing of all.
Good morning Craig. Your videos are the very best how to's. You explain everything very clearly. I watch every one of your videos and learn something every time. Thanks for sharing.👍👍
I think,one other problem could be that vacuum line(pipe) could be little cracked and fuel pump wont work very well and dont pump enough fuel. Thank you very much for this detailed explanations.
Thanks a lot for the video... it really help me to solve the problem that i was having (choke cable was not fitted properly and leaking/breathing through the cable seat. Thanks again :)
Excellent video it seems that you are a specialist as your name on this video, I had a problem with the manifold loose the 2 screws that connect to the carburetor but i noticed that the gasket is missing so this may be the problem. Thank you
An excellent explanation of the malfunctions of this type of carburettor! Maybe some advice about the fuel used. NEVER use alcohol containing petrol, this will dissolve the rubbers of the membranes. You can only see this clearly if you hold them up to a light. You then see the fine grid of the fabric on which the rubber was attached. These rubber particles contaminate the carburettor and all small holes need to be cleaned, sometimes very small ones.
Good video, working on my Strimmer engine right now, after many years of no use (because it wasn't working correctly), found several faults, partial fuel filter blockage, leaking fuel tube inside of fuel tank and air filter blockage. Ran it after rectifying the faults and found it working on partial choke quite well, will try it under load tomorrow. Was going to buy a new electric strimmer so if successful you will have saved me much needed money (Pensioner). Many thanks for your info.
Great video. I had replaced the carb on my Echo trimmer and couldn't get it tuned. Watched the video and decided that maybe I should take it all apart and start fresh, thinking that maybe there was a leak somewhere. Took off the carb and even though I thought I still had the screws in far enough to hold the gasket, it was off on one side, hanging down. I continued checking tightness of everything and put it back together, making sure that the gasket was correct. Wet through setting it up from scratch again (idle speed, High and low needle valves) and had it running like new in a few minutes. Thank you for the great explanation.
I found the problem is usually an air leak in an old fuel line, the solution is cut off the cracked end and reconnect. It could also be in an old tank where the tank take up hardens and expands. Replace the old parts or wrap teflon tape to make the take up plug in tighter.
Carburettors, don’t you just love them!? Fuel/air mixture can be critical on a two stroke engine. I learned about fine tuning carbs when I had my tuned Yamaha 250 and 350 RDLCs. I certainly knew my way around Mikuni VM 26s and 28s.
@@TheRepairSpecialist I checked the tank, I even bought another tank and was going to install it today. But I never tested the vent. I'm certain this is what's happening. The tank is warped kind like there was excess suction inside it like a gas can does in the cold. I don't know why it didn't occur to me sooner, I've even seen it suggested in other videos. I've been through the whole outboard at this point. It runs like a top until you open her up. That's gonna change today thanks to you sir. This old pontoon has a fuel fill and vent attached to a broken trim ring and they're all super weathered. I'll replace it all but for today I'll take your suggestion and leave the cap slightly loose. I can't wait for my family to wake up lol. Your walk through on how all this stuff works and works together is the best on RU-vid. I'm grateful to have found your channel
Excellent channel. My Stihl 600BR used to run well before a Stihl certified tune up. Now, it runs when the machine is warmed to room air, started and operated above 0 degrees C. At -30 degrees C, it starts and idles but bogs down as the throttle is advanced. I’m curious how to diagnose and fix this.
Hi, have a weird problem where line trimmer starts and runs and i can add more fuel or lean per the screws but after a period when hot, it wont idle anymore. Part choke saves it but it not happy engine!! Have switched carbs (3) and gravity fed fuel and even cut the pump vanes off and fed it fuel in case the pulse channel was dying after a period, but why would that happen? unless piston bore clearance and pressures suddenly drooped off. so cant be fuel delivery problem or vent valve as bypassed all that. Also i quickly checked for spark when it died and seemed to be still sparking but too weak when hot? Could it be simply a weak coil thats dying when warm and spark not strong enough? Also one time after 15 mins it refused to go above half revs even when i pumped the throttle. Electronics in coil failing and restricting RPM? a few mins later it was back to full power and rev up down ect. I honestly thought this machine was haunted as intermittent running problem with plenty of juice available on start so good fuel and spark then but not good spark when warm? Would part choke save a weak spark situation ? Also when after start, idle screw needs to be changed a bit, it wont lock on to one setting. Comp test was around 100psi. cold. Could the engine be bleeding off suction and pressure when hot as its old? . 3 carbs , 2 new and 3rd completely rebuilt on this machine of varying throat sizes but they all idle and fail the same after about 15 to 30 mins. same symptoms. Also pressure tested engine and got 9 lbs, no leaks but replaced all seals and crank seal in case they were bleeding when hot. So engine is air tight. Baffling!! thanks if you can help...
Id be trying a coil,,,,i know its easy to just say and throw that out there from a chair but i would try a new coil and spark plug. This is of course is figuring all of the other basics are good which sounds like you got covered (vacuum leaks, etc). Love to know what you find. Stay safe and good luck
Do you have a spark arrestor on that unit? Pull it and check it. If clogged, use a propane or mapp flame to char it and brush off the soot. Interesting problem. I'm gonna assume you fixed it or had it fixed. What was the problem?
@@alext8828 Hi, i found the problem. You need about 90 psi for 2 strokes to work and i was getting 100 cold but only 70-85 hot?? and thus it couldnt run but took 10-20 mins to get hot and bleed off. Caused by worn bore and rings. Put new rings and checked hot and back to about 100 but the piston the bore clearance ect is not good so this wont last too long and that will be that for this machine . Good learning experience and i had to work this out myself as engines are supposed to increase psi as they warm up not the opposite. 2 strokes are very picky as they have to compress and suck the mixture in, so clearances are very tight. Thanks for replying. all good now..
I've just dealt with my " the handy" strimmer. The beast kept dying off choke. The fuel supply line had snapped. No vacuum equals no draw of fuel. Resulting in a dead cut.
I've given up on rebuilding the fuel system on my chainsaw ,which I've had for 25 years and replaced fuel lines an carburetors I'm done! I'm going electric 40v 18"
Wow...very very well explained. Just what i need to fix my weed eater.... BUT my carb got only one screw,, just above where the inline fuel pipe connects with the carb... 🤦♂️ There is no H or L... 🤷♂️
Thank you for your nice feedback. Its very much appreciated. Take a look at this other video of mine, which explains the basics on single adjuster screw systems on carburetors. It might help make things a little clearer. Here it is: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-oDkVVL0CJqk.html . Thanks. Craig
The 2 stroke engines must be able to exhale freely. If the engine idles but has no power, or simply won’t accelerate, and you checked all the first eleven things you might check for restriction to the exhaust. This maybe a piece of woven wire in the muffler that has accumulated over time exhaust oils baked on the screen installed as a flame, or spark arrester. Exhaust holes at the piston exit can build up crud and restrict the exhaust also. This takes many seasons to accumulate, but the seasons pass quickly, it maybe older than you remember.
Thank you for this video, however, I have a weedeater that I replaced the fuel line, the carburetor (it's the recommended for the brand, not a generic brand), the gaskets and the spark plug. The engine is still bogging down when I try to push the throttle, and it has a baging noise that seems like the piston is hitting something. What could it be?
Hi. Thank you for your nice feedback. I really appreciate. I would start by removing the carb again and look into the induction tube at side of the piston. Use a torch. See if it has any scoring marks on it. Turn the stop switch to off and turn over the engine slowly to see it clearer. If there is scores present then this is showing wear on the engine that needs to be corrected by an engine strip down or replacement of the whole machine. Also, I would remove the exhaust and look down the exhaust port hole to see if i could see the same sort of scoring. If so, then same outcome unfortunately. I hope this helps as a starting point considering the other things you have already done. Thanks Craig👍
SIR i'd like to ask, i have Chinese chainsaw 52CC (stihl MS5200 - not genuine Stihl) bought it last December 20, 2021 after typhoon RAI hit in my country that wreaked havoc in Central Visayas area, Philippines. After weeks of continues used by cutting trees the engine started to run abnormally up until now, though still usable. After few minutes of running, when I revv the engine the sounds will changed (PROT PROT PROT SOUND) like out of fuel and then I dies, when in fact it was half full-full tank, but when IDLING the sound is normal. I already adjusted the LH and Carb dials so I can get the correct air and fuel mixtures. It will just run few minutes and back to the problem again. So, what I did was I cleaned the carburator (disassemble & assemble) and the clutch (i didn't detached) brushing only. Still the problem not solved. LAst week I bought new Carburator and Fuel breather and installed it correctly, after few minutes of running the still the problem persist. The PROT PROT PROT sound not solve and then the engine dies. WHAT COULD BE THE CULPRIT? I've been searching this problem months now in the internet, but I haven't seen any videos/articles that could address my chainsaw problem..I'm thinking Maybe you have an answer for this.. Hoping for your reply. Thanks in advance.
Oh small 2 strokes…. I have a collection of mixed Echo and Stihl, my diagnostic starts with throwing on a new carb and usually that solves my problem(s)
