[AllanC]

I am trying to get a Troy-Bilt 2 cycle gasoline trimmer to run. Unit is only several years old and was running earlier in the year but stopped. Pull repeatedly on starting cord but no start. Gasoline is correct mix of 50:1 fuel to oil. I removed the spark plug and it was fairly clean but decided to clean and gap. I hold the spark plug connected to its cable against the head and pull starter cord rigorously. Consistent spark jumps the plug gap so I know that the ignition module is functioning.

I opened the housing with the air filer and sprayed starting fluid into the carburetor opening. Repeated pulls on the starter cord and spinning the engine but still no start. I am stumped. Any engine that gets spark and has starting fluid sprayed into the intake should start and run a few seconds. Two cycle engines are pretty simple so I am befuddled as to the next step.

Picture below of carburetor in link. Could I have a flooding condition with the carburetor and the overly rich fuel mixture along with starting fluid is causing the no start?

Dropbox - Gasoline Trimmer (at https://www.dropbox.com/sh/j24mgzy8bv85zsr/AAC8LRtkQ6tNFxAVJaxPqjoca?dl=0 )

 

[Doug D]

How old is the fuel and is it E10? I've learned the hard way that E10 is not good for newer small engines and over time there will be carburetor problems. As a first step may try fresh fuel? Gasoline older than three months can be considered to be "stale". Only thing I can think of since you say you do have spark.

I had to replace the carburetor on my self propelled lawn mower (also a Troy-Bilt w/Briggs-Stratton engine) a few years ago. At the time the tech recommended using Startron (an enzyme that neutralizes the ethanol) or use non-ethanol fuel. This past month I started using non-ethanol fuel instead of E10 mixed with a capful of Startron. Engine seems to run smoother and starts on one pull. With E10 it sometimes took up to 10 attempts to start the first time.

 

[Bob Lincoln]

But if it were the E10 or bad fuel, it should have at least attempted to start when he sprayed starting fluid, right?

 

[Doug D]

But if it were the E10 or bad fuel, it should have at least attempted to start when he sprayed starting fluid, right?

Good point. Maybe the carburetor is gummed up just enough to cause starting issues? Since he has spark it seems to point to the carburetor. I know old fuel can be a problem (but not always) when trying to start small engines. I was trying to eliminate one possible cause.

 

[NYBo]

Since you have spark and fuel, the third side of the combustion triangle needs to be checked: compression.

 

[Bob Lincoln]

Yeah, not that familiar with small engines, but maybe a ring fractured?

 

[AllanC]

. . . How old is the fuel and is it E10? I've learned the hard way that E10 is not good for newer small engines and over time there will be carburetor problems. As a first step may try fresh fuel? . . .

Fresh fuel mixed in proper proportion 50:1 with oil. I am sure the gasoline has 10% ethanol. Fuel lines are clear as I removed the fuel tank and tipped it. Gravity flow of fuel through lines so not plugged.

. . . But if it were the E10 or bad fuel, it should have at least attempted to start when he sprayed starting fluid, right? . . .

My exact thoughts. Any engine with spark and timed right should start with a spritz of starting fluid through the carburetor but not on this machine.

. . . Since you have spark and fuel, the third side of the combustion triangle needs to be checked: compression. . . .

Good point as you have to have spark, fuel and compression. I can remove the spark plug, insert thumb into spark plug opening and spin the engine and see if I have any noticeable compression.

I discovered that Troy-Bilt engines have a "jump start" port on the engine. I had to research and found there is a tool adapter with a hex drive that fits into the flywheel. Attach an electric drill and you can spin the engine for easier starting and avoid yanking on pull cord. I am going to try that and see if I can get the engine to fire.

I will do some more detective work and then report back. Thanks for all the good ideas.

 

[AllanC]

I purchased a jump start adapter for a Troy Bilt engine. It is an adapter that fits an electric drill. You engage the flywheel and allows you to effortlessly spin the engine at high rpm to get it started. This adapter was $9.97 + tax at Lowe's.

I first removed the fuel lines and sprayed starting fluid into the carburetor throat. Spun the engine crankshaft with electric drill and manipulated the throttle. Still no start. I then reattached the fuel lines and primed. Spun the engine crankshaft again and finally got the engine to run for about 10 seconds at full throttle.

I reduced the throttle lever and engine spit, sputtered and died. Difficult to restart. So at this point I have good compression, good spark and erractic running. I think I need to remove the fuel metering screws and make sure the passageways are clear. Maybe it is just an adjustment problem but the engine is not that old. I have never opened a 2 cycle carburetor so this will certainly be an adventure and learning experience.

Having a means to use an electric drill to spin the crankshaft is a big help. Yanking on a pull cord is frustration.

To be continued.

 

[ImperialCrown]

How does the spark plug tip look now? These can easily carbon-foul if rich. The carbon conducts at spark voltages and the spark will ground-out instead of jumping the gap and firing the mixture reliably.
I have a small sandblaster tool for cleaning fouled spark plugs. A wire brush, solvent and compressed air may work in a pinch for cleaning a spark plug.

 

[AllanC]

. . . . How does the spark plug tip look now? These can easily carbon-foul if rich. The carbon conducts at spark voltages and the spark will ground-out instead of jumping the gap and firing the mixture reliably. . . . .

I removed the plug last night and found it to be darkened somewhat. If this was a 4 cycle engine then there would be concern about an overly rich fuel mixture. But since a 2 cycle burns and fuel - oil mixture I thought a darkened plug should be expected??? Anyway I used sandpaper and cleaned the grounding terminal and the electrode tip. So I am pretty confident a fouled spark plug is NOT the issue.

 

[GaryS]

I'm surprised there haven't been more responses about having fuel issues. I've had to disassemble and clean carburetors on at least one or two of my small engines every year, with 2-cycles being the worst. Modern fuel is horrible, and despite seasonal draining, new filters, and always using fresh fuel, carburetors and fuel lines gum up.

This spring it was my pressure washer that first would not run at all. I disassembled the carb, soaked in carb cleaner and used compressed air to blow everything clear. Still wouldn't run. The second time, I found a microscopic, sticky glob by running a paper clip through the passages. Carb cleaner wouldn't dissolve it. It finally ran, but only for a minute or so and then it had to sit for two or three minutes before doing the same thing. When I pulled the fuel line again I could see that it ran too slow. I found more sticky residue inside the fuel tank that was restricting the flow. Lots more cleaning to remove that, but now it finally runs.

Current problem is my second-season leaf blower. It has lost power and will only run on half-choke. Last fall it was my Troybilt Roto-tiller, and a year-old Husqvarna trimmer that needed cleaning. I finally gave up in disgust trying to get my edger to run long enough to do my lawn more than once, so I threw it out. A three-year-old Husqvarna mower sits in a corner waiting for me to see if I can get it to run at high enough RPMs to cut.

Hot Texas summers and modern fuel don't get along at all. Not saying it's your problem, but I'm getting paranoid when it comes to small engines.

 

[Bob Lincoln]

This is one reason why I use all hand tools in the yard.

 

[ImperialCrown]

Rebuilding carburetors has to be considered a 'maintenance' task. I don't blame the fuel. Most carbs are easy to get parts for, simple to rebuild and adjust.
Sitting for months without use (even emptied of fuel) can shrink seals and gaskets. I had a brass float corrode a hole in it by resting at the bottom of an empty aluminum fuel bowl.
At least the solid state ignition systems are mostly trouble-free and mechanically I don't think that 2-cycle engines have ever been better.
The spark plug/fuel and oil must be what the manufacturer specifies and don't be taken in by the marketers 'better than OEM' ploys.

 

[Doug D]

I'm surprised there haven't been more responses about having fuel issues. I've had to disassemble and clean carburetors on at least one or two of my small engines every year, with 2-cycles being the worst. Modern fuel is horrible, and despite seasonal draining, new filters, and always using fresh fuel, carburetors and fuel lines gum up.

This spring it was my pressure washer that first would not run at all. I disassembled the carb, soaked in carb cleaner and used compressed air to blow everything clear. Still wouldn't run. The second time, I found a microscopic, sticky glob by running a paper clip through the passages. Carb cleaner wouldn't dissolve it. It finally ran, but only for a minute or so and then it had to sit for two or three minutes before doing the same thing. When I pulled the fuel line again I could see that it ran too slow. I found more sticky residue inside the fuel tank that was restricting the flow. Lots more cleaning to remove that, but now it finally runs.

Current problem is my second-season leaf blower. It has lost power and will only run on half-choke. Last fall it was my Troybilt Roto-tiller, and a year-old Husqvarna trimmer that needed cleaning. I finally gave up in disgust trying to get my edger to run long enough to do my lawn more than once, so I threw it out. A three-year-old Husqvarna mower sits in a corner waiting for me to see if I can get it to run at high enough RPMs to cut.

Hot Texas summers and modern fuel don't get along at all. Not saying it's your problem, but I'm getting paranoid when it comes to small engines.

In regards to the sticky residue that sounds like either the fuel turning to a varnish type substance or what ethanol laced fuel (E10) does to the fuel passages. Not sure if any is available in your area, but I strongly recommend non-ethanol fuel. E10 is the reason I had to replace the carburetor on my Troy-Bilt lawnmower (Briggs-Stratton engine). Or try using a product that was recommended to me - Startron. It is an enzyme that neutralizes the ethanol. An 8 oz bottle is $7.99 or so - only need a capful to treat a gallon. Ever since I have been using non-ethanol gasoline my mower seems to run smoother and definitely starts much easier - usually on the 1st pull. I'm fortunate that one local station does have non-ethanol available though it is far more expensive than E10 - $1.979 for E10 87 octane and $2.539 for non-ethanol gasoline (87 octane).

Bob - believe it or not they still make and sell non-motorized lawnmowers. It I had a smaller lawn to cut I would consider getting one. I think our local Tru-Value has them or they can at least be ordered.

 

[Bob Lincoln]

Bob - believe it or not they still make and sell non-motorized lawnmowers. It I had a smaller lawn to cut I would consider getting one. I think our local Tru-Value has them or they can at least be ordered.

I have had one for 16 years. That's why I said, I have all hand tools for yard work.

 

[chargermike]

Did it run fine the last time it was used? If so I will bet it`s the carb if fuel sat in it for a period of time. I run the canned fuel that is sold at home depot, lowes etc. Haven`t had a single issue since using it. As least use it for the final run of the year before putting it away. That fuel lasts longer and doesn`t have the E10 in it. Also, a new carb should be cheap to replace.

 

[GaryS]

I wish I had non-Ethenol fuel available locally, but the nearest advertised source is over an hour's drive away, and it's almost double the price. With the summer heat, buying in larger quantities doesn't do the job either, as all fuels break down quickly in summer...when I'm using the equipment. I'll have to look for the Startron product, as I wasn't aware of it...thanks Doug.

Bob, if I wasn't 75 years old and taking care of a two acre lot in 100 degree heat, I'd consider more hand tools!

 

[AllanC]

. . . . Rebuilding carburetors has to be considered a 'maintenance' task. I don't blame the fuel. Most carbs are easy to get parts for, simple to rebuild and adjust. Sitting for months without use (even emptied of fuel) can shrink seals and gaskets. . . . .

I tend to agree with this statement that keeping a carburetor clean on any engine is basic upkeep and is essential for a well running engine. Classic / collector cars that sit unused for longer periods of time tend to have this problem.

. . . .Did it run fine the last time it was used? If so I will bet it`s the carb if fuel sat in it for a period of time. I run the canned fuel that is sold at home depot, lowes etc. . . . . That fuel lasts longer and doesn`t have the E10 in it. Also, a new carb should be cheap to replace. . . . .

Gasoline trimmer belongs to my son-in-law. I questioned him about using a fuel stabilizer or draining carburetor before the long winter hibernation. I do not think that was done so as mentioned I suspect some carburetor passageway clogs. Being a smaller carburetor I think sitting unused and today's fuel can get gummed up in a hurry. Also since oil is mixed with the fuel this might be an additional, contributing factor to carburetor clogging due to non-use.

But I have had lawn tractors powered by Briggs and Stratton 1 cylinder engines. In November each year I drain the fuel tank and then run the engine until the carburetor is dry. Then the following spring season I add fuel and the engines start easily and run well. I go years and years without carburetor problems.

My 1991 Dodge Dakota with 5.2 liter V8 and throttle body injection has never had a fuel clogging problem. It tends to sit 4 - 5 weeks at a time between engine startups. If the engine had a carburetor I would probably have had to remove it several times in the 24 years I have owned it and cleaned internal passageways. I am somewhat amazed that I have NOT had a fuel delivery issue with this vehicle and its intermittent use.

Your comment about just replacing the carburetor makes a lot of sense. I have seen them for about $20 online and one cannot justify a lot of labor expense in cleaning. But I think that will be a last resort as I want to learn about these devices and see if it can be fixed easily.

 

[Doug D]

But I have had lawn tractors powered by Briggs and Stratton 1 cylinder engines. In November each year I drain the fuel tank and then run the engine until the carburetor is dry. Then the following spring season I add fuel and the engines start easily and run well. I go years and years without carburetor problems.

Kind of related topic. Back when I was young and daring, I bought a '82 Kawasaki KZ550. It had 4 synchronized carburetors. Winterizing included filling the fuel tank full (rust prevention), then turning the fuel line valve off (it had three setttings, off, on and reserve), then drain each carburetor to prevent any varnishing. I also added Sta-bil to the fuel in the tank. Come spring all I had to do was check the battery (charge if necessary), turn the fuel line on and it usually fired right up.

I'm hesitant to drain the fuel on my lawn mower engine (Briggs & Stratton) as part of the winterizing process. I did that one year and when I added fuel in the spring it began to leak from the bottom of the carburetor bowl. Turns out the gasket had dried up. Ever since then I'll fill the tank with fuel, but make sure I add Sta-Bil to the fuel before doing so.

 

[Rickorino]

What I find the most common issue(besides carb) is the fuel lines fall apart, inside or outside of the tank. There is often a filter on the end of the fuel intake hose. I have also run into several units where the head bolts loosen. Sure you might feel compression but often there is not enough to pull the fuel into the cylinder from the carb. If you tear into the carb, get the rebuild kit, you likely will not be able to reuse the gasket(s) or diaphram once they are peeled.