I cannot make these run!!

[Dirtcrasher]

I probably have 7 ziplock 1 gallon bags, each filled with numerous fastners, a pull start, a carburetor, a spark plug and other various other items from 2 stroke motors.

I COMPLETELY SUK at getting chainsaws, lawnmowers and weedwackers to run. Mainly chainsaws are beating me down bad right now, so bad that I bought an 18V cordless Dewalt Chainsaw. I am pulling muscles trying to pullstart these POS, so I got something that works, the minute I need it!!

I clean the carbs, replace the plug and put fresh fuel in, and they're dead; They're ALL DEAD!! This is getting ridiculous, I cannot make these WAMA ZAMA BAMA carbs to work or I am lacking fundamental skills with this type of equipment.

Seriously, does anyone else go thru this?? I have spark, compression, clean carbs and a new plug, but they just don't run



I try to apply all my basic engine knowledge from much more difficult combustion engines, but these things continue to elude me....

[El Camexican]

Same issues here. Tossed 3 Homelite trimmers before discovering exact replacement carbs on eBay for $15 bucks.

I don’t know if it’s todays fuel, or low quality rubber, but the primers and diaphragms just don’t last the way they did 40 years ago. My Dad has small Homelite chainsaw he bought around 1970 and he uses it at least 3 hours a year and as far as I know all it’s ever needed was chains and a couple guide bars. Same with mowers from the 60’s and 70’s, let them sit all winter and they started on the second or third pull 6 months later.

[83ATC185]

You are not alone. I bought a new cub cadet weedeater, paid a little extra for the straight shaft higher end model. Used it twice before it became damn near impossible to start. Suspected ethanol swelling the lines and diaphragm. Pulled it apart, nothing looked out of whack so i got ethanol free gas and got it running. Still impossible to start without wearing yourself out. Threw it in the corner of the shop and its been there since. My thoughts, I think the problem is that the mixtures are all set from the factory and are non adjustable because of emissions laws and if you're in a different altitude and climate than it was built in its not gonna run right

My stepdad's ancient stihl weedeater that he threw together from spare parts in 1990 something can sit all winter with old gas in it and he can fire it right up. My dads 300th anniversary husky chainsaw has been laying in the yard under a tree for 6 months and i bet you could go crank it right now but its like a half liter saw and you're gonna pull muscles regardless

[ironchop]

I gave away a three year old Stihl weed eater that was new in 2005 because every single year I was rebuilding carb even if I drained it before I stored it in a heated garage.

They are all making pieces of crap now.

I got an electric weed eater.

My neighbors newer Husqvarna chainsaw isn't quite as bad but I'm scouring yard sales for old chainsaws from the 80s or earlier like a Homelite, Husqy, Stihl, or Jonsereds. Those are the brands I see still running great after 30 yrs and easy to start. Probably hard to get parts for. There's no reason to have to do this much carb work every year

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[El Camexican]

You are not alone. I bought a new cub cadet weedeater, paid a little extra for the straight shaft higher end model. Used it twice before it became damn near impossible to start. Suspected ethanol swelling the lines and diaphragm. Pulled it apart, nothing looked out of whack so i got ethanol free gas and got it running. Still impossible to start without wearing yourself out. Threw it in the corner of the shop and its been there since. My thoughts, I think the problem is that the mixtures are all set from the factory and are non adjustable because of emissions laws and if you're in a different altitude and climate than it was built in its not gonna run right

My stepdad's ancient stihl weedeater that he threw together from spare parts in 1990 something can sit all winter with old gas in it and he can fire it right up. My dads 300th anniversary husky chainsaw has been laying in the yard under a tree for 6 months and i bet you could go crank it right now but its like a half liter saw and you're gonna pull muscles regardless

Those preset carbs are BS. If a guy had the time I believe there’s a plug that could be drilled out and tapped if one had the parts and tools.

[ironchop]

Those preset carbs are BS. If a guy had the time I believe there’s a plug that could be drilled out and tapped if one had the parts and tools.

Agreed. I had a push mower and a Coleman gennie (both 4 strokes)that both carbs had steel plugs rusted out of them inside somehow. I wonder how much water is in the fuel here locally.

The lawnmower I gave away too because a replacement carb was almost half as much as I paid for the whole mower new. I had to pay $135 for that replacement carb for the generator but went ahead and did it because the generator was free to me so it was worth the investment. Both were stored in a fairly climate controlled garage.

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[OTAlucard]

There's multiple reasons why you're all having problems.

I am too tired to go into detail but. I've rebuilt too much way too many pieces of equipment. But if it isn't high quality I won't even mess with it. You need to find a Shindaiwa t25 or t270. They run forever. Stihl weedeaters suck. Sorry. I don't know why people have a love affair with the pro models they all suck. I've had them all and still run them they'll start up and run but have problems.

They get air leaks too easily. Plus stihl didn't even make their own engines zenoah did.

The br400 to 420 backpack blowers from stihl are great. Stay away from anything else 4 mix. Is bullshit.

Most stihl stuff has a stamped connecting rod. Junk. Junkkkk. Run your oil at 40:1 minimum and you'll have better results.

Either put a ton of atf in the gas and pump it through the carbs. Or.

Do what I do. Run them for 10 seconds on av gas with a high oil mix rate. I've had chainsaws start up and run fine after 2 years. Generators etc. The lead protects it seems like.

[sweetip2000]

Use the stabil with 89 octane. Dont use 87 or 92. Alcohol. Water and less gasoline = more problems. Everything is made in China so now we have Chinese problems with shitty fuel. The odds are against us for sure. Use the stabil all year round for everything. Hope all is well. This winter really sucks here in the north east this year.

[fabiodriven]

Steve is it the old McCulloch's you're having problems with? I don't have first hand experience with those but they're supposed to be fantastic saws. Something is definitely awry here.

My Husqvarna 576XP bought new in roughly 2012 has been flawless. My remanufactured Husqvarna 435 bought around 2013 has also been flawless. My Husqvarna straight shaft weed eater needed the fuel lines replaced once after about two years of ownership. It was definitely premature but it was easy to fix. It's run perfect otherwise.

All of these machines start reliably hot or cold every time. I use Star Tron fuel treatment. People love Stihl, and Stihl is a great manufacturer, but I've had Stihl and it wasn't a Husqvarna. I own all Husky now and their stuff has worked out fantabulous for me.

[Rob Canadian]

Those little engines always got me for most part when they don't run. I hate B&S... Had my run in with a gas weedeater. It got the best of me after 1 year. Cheaper modle... I have a electric one now.

Mower is good. 20 year old craftsman.

You are not alone.

[plastikosmd]

Ya, I thought it was just me. U ain’t alone

[RIDE-RED 250r]

Hey Stevo!

I have been playing with saws for awhile now, and while I can't promise I will be able to get you up an running without putting my hands on them, I'll give it my best.

After reading your post, it sounds like you are having a fuel delivery issue. There are a few reasons this can happen.

1: Carb issue. You say they are clean, but are they REALLY clean? Did you disassemble the carbs completely, including pulling the welch plugs and remove the mixture screws? Under the welch plugs, you will find your tiny fuel passages where the metered fuel is pulled into the carb venturi. These passages are very small and the slightest bit of contamination will give you issues. Also, there are sometimes tiny little screens under those welch plugs put there to prevent small debris from entering those passages where it is much trickier to clear. When the screens get obstructed, you will not get adequate fuel into the venturi. Complete disassembly and verification that all passages are clear is a must to eliminate the carb from the list of suspects.

1A: Carb metering lever height/metering needle not stuck/sticking. This is relatively easy to check when you know the make and model number of your carb. Most carbs the metering lever should be even with the carb body. Some however are not, having your carb make and model number will help determine proper metering lever height. (basically, a needle and seat that rapidly opens and closes allowing fuel from the pump diaphragm side of the carb to enter the metering side, feeding the fuel to the mixture screw passages). Too low and it will be starved for fuel and barely run, if it runs at all. Too high and it will flood the case with raw fuel as if you poured it into the saw with a funnel.

1B: Carb impulse system. These carbs also act as your fuel pump to draw fuel from the tank. It utilizes the pressure/vacuum cycle in the crankcase to drive the pump diaphragm in the carb (found on the opposite side of the carb as the metering diaphragm) The most common methods of providing crankcase impulse to the pump side of the carb is either A: a small hose connecting the case or base of the cylinder directly to the carb in the case of a saw that has a rubber intake boot or B: an impulse port in a solid intake block that connects the carb to the cylinder. You will see corresponding impulse ports on the mating surfaces of the intake on the cylinder as well as on the mating surface of the carb where it meets the intake block. These ports are pretty small, about 1/16" give or take.

2: Fuel lines and filter. You want to make sure the fuel line and filter are in good working order, especially if they are getting pretty old and/or ethanol fuel is used.

3: Crank seals. As with any 2-stroke on a wheeler, chainsaws need a good seal from the crank seals in order for everything to work right and run. You can rig up a pressure/vacuum tester pretty cheap. And you want to check both pressure and vacuum if you have the means.. Plug the exhaust by taking a piece of inner tube and sandwiching it between the muffler and the exhaust outlet, just like making a homemade gasket with bolt holes and all, only don't cut it out for the exhaust outlet. For the intake side if you have a solid intake block between the carb and cylinder, you can fashion an inner tube plug the same way you did with the exhaust. If it has a rubber boot and the intake opening is round (as most with a rubber boot are) you can usually find an expansion plug at a hardware store that will get the job done. Now that the intake and exhaust are sealed up, crank the engine to BDC and you can rig up your method of pressurizing the engine via the sparkplug hole using a compression tester hose connected to regulated air with a shut off. Just like a 250r, you want to pump it up to 8-10psi and make sure you don't lose more than 2psi in 10 minutes ideally. Use the same setup to pull a vacuum if you have a vac pump.

All of that said, will they run if you drop a tablespoon of premix right into the sparkplug hole??

And..... REMEMBER THE DAMNED FLYWHEEL KEY! LOL! But seriously, no joke... a shifted flywheel will disable a saw just like anything else..


Jet limiters: Well what can I say... THEY SUCK! Most are fairly easily defeated (or as our hippy friends in the EPA would say, "tamper with") The kind with the plastic caps with restrictor tabs that snap over the jet screw heads are probably the easiest, a razor blade clamped in a small pair of vice-grips and heated up with a propane torch makes quick work of those, and you still retain the small flathead screwdriver compatability by keeping the caps but cutting the restrictor tabs off of them. Lately they have gotten more creative, but you being a machinist, I'm sure you can find a good way of disposing of those. Removing jet limiters is paramount to the ability to PROPERLY tune your 2-stroke OPE! I have run brand new OPE out of the box with the jets set as rich as the limiters would allow that were obviously set too lean... no power at all. Defeat the limiters, re-tune, and they run like they should.

Back to the carb disassembly, I believe Walbro has some very good instructional vids on their small diaphragm carbs. Walbro, Zama, Tillotson, Bing, all different brands of carbs used on saws but all basically the same. Let me see if I can find that vid and post a link. It is very informative. BRB

[RIDE-RED 250r]

Here ya go Stevo. Alot of stuff I'm sure you already know, but I think some parts if this vid will help better explain some of the stuff I was referring to about the carbs.

https://www.youtube.com/watch?v=cDaOcNrS6BM

[coolpool]

Fabio and ride red touched on the first thing I do with a chainsaw/whacker small engine that is cranky, replace the fuel line with quality stuff right up to the weighted pick up tube in the tank. I don't like hocus pocus much but the Stabil Marine 360 works for our fuels up here. And look at your primer bulb (if so equipped) for miniscule cracks.

[Dirtcrasher]

Steve is it the old McCulloch's you're having problems with? I don't have first hand experience with those but they're supposed to be fantastic saws. Something is definitely awry here.

My Husqvarna 576XP bought new in roughly 2012 has been flawless. My remanufactured Husqvarna 435 bought around 2013 has also been flawless. My Husqvarna straight shaft weed eater needed the fuel lines replaced once after about two years of ownership. It was definitely premature but it was easy to fix. It's run perfect otherwise.

All of these machines start reliably hot or cold every time. I use Star Tron fuel treatment. People love Stihl, and Stihl is a great manufacturer, but I've had Stihl and it wasn't a Husqvarna. I own all Husky now and their stuff has worked out fantabulous for me.

Yes John, that one too doesn't want to run either I'll post a pic of the other 2, 1 being a Pro Mac 40 which is a cool old saw.

That 50$ saw is the one I pulled a muscle on the other day and I was screwed, I had no options. I had to 2nd day mail (Amazon) me this 20V DeWalt Chainsaw so I could get out my front yard!!, but it works!!