Kerry & Kathy
Member #007
I wanted to share a frustrating experience while troubleshooting a Cub Riding Mower that would not start after sitting over the winter…while adding a caution on the use of ethanol-blended fuel and replacement fuel system components.
I do regular maintenance on all my vehicles, tractors and mowers and have done so for many years…but this situation is one that I have never seen before and one I wanted to share.
I HATE ethanol based autogas. Especially for vehicles or equipment that sit for prolonged periods of time… such as tractors, chainsaws, weed eaters, and lawn mowers. Ethanol has created many problems with attracting moisture from the atmosphere into the gas…then having the water settle to the bottom of the tank. I had an 89 bronco with a new galvanized aftermarket tank that water rusted thru the bottom of the tank in less than eight years, creating multiple pin holes that leaked. In the past, I would always install shut off valves in the fuel lines and run the float bowls dry on my riding mowers after using, only to have water collect in the bottom of the plastic gas tanks requiring that the tanks be drained every spring. Often the ethanol would attack the rubber O-rings, gaskets and seals requiring replacement as needed every 3-4 years.
With three mowers, two working tractors, two weed eaters, and five chainsaws…it was becoming a genuine PITA to constantly have to do more than routine maintenance. I converted to lithium battery powered chainsaws, tree trimmers and weed eaters but the mowers were switched to 91 octane ethanol free gas. After draining the fuel lines, filters and gas tanks, of any ethanol blended gas, and switching to ethanol free gas…I thought that would help resolve the ethanol fuel issues for good. It did not.
When trying to start the Cub riding mower in Farmington two days ago…I could not get it to fire. It would crank easily…but would not start.
I checked the ignition first…plug was good, CDI magnet air gap was set to minimum tolerance and ignition tester showed a healthy spark.
Checked for fuel at the carb by pulling the fuel hose…no gas.
Checked the crank pressure actuated fuel pump and it was working properly.
Checked the fuel line between the carb to fuel pump to fuel filter…and all lines were clear.
Finally when I checked the fuel line from the tank to the fuel filter…it was plugged solid. Attempting to blow air in the line met with total resistance. This fuel line is about 4 ft long and snakes from under the rear plastic fuel tank over the transaxle, under the frame, along the frame rail, through an access hole in the frame, under the steering sector, up behind the engine and finally to the fuel filter. It is a PITA to replace and wire tie back securely. I replaced the line four years ago after it was damaged by a deck v-belt…with generic automotive fuel hose purchased from a farm supply. So…rather than replace it I disconnected both ends and forced 80 psi of compressed air through the line to clear it. Surprisingly there was water in the line…along with small bits of rubber. However not enough debris came out of the hose to explain why it was clogged so badly. But…compressed air was getting through…so I assumed fuel could as well.
Once I had compressed air flowing through the line I reconnected the fuel line at the tank and fuel filter. Put everything back together expecting the engine to fire right up…and NO CHANGE..!
I pulled the gas line back off again and tried to blow through the line…and it was still plugged, even though I had just successfully run 80 psi of air through the line. I was baffled. The line was ¼” I.D and I had a dowel rod that was 3/16” in diameter. When I tried to run the dowel through the line it would go in about 1 inch and stop. This occurred from either end. The line was plugged tight. Then I split a portion of the line lengthwise and found the problem. Even though I had been running ethanol free gas last summer, the ethanol I had used the previous three years had attacked the rubber hose and caused it to swell shut. In some sections the interior of the hose allowed flakes of rubber to separate into the fuel. To be on the safe side... I then pulled the carb, drained and cleaned the float bowl and replaced the fuel filter.
Replacing the fuel line with a high-quality Honda brand fuel hose I use on my motorcycles solved the problem and the engine started right up.
Then I recalled that last summer I had a couple of issues with hard starting and running lean with popping in the exhaust…an indication of a lean mixture or leaking valve. But…it was sporadic. It would occur briefly…then go away. Apparently, the hose restriction was reducing fuel flow even last year causing the engine to periodically lean out. Hopefully I haven’t burned a valve or damaged the piston…but it appears I got lucky. So far it is running normally.
The moral of this account is to avoid ethanol-blended fuel in any equipment or vehicles not specifically authorized to use ethanol. And even if they are…if you replace any fuel lines or fuel components that are gasoline rated…they may NOT be rated for ethanol. I would suggest only using a quality fuel hose that is rated specifically for ethanol.
Or…simply avoiding ethanol entirely on all your equipment that is used seasonally.
I do regular maintenance on all my vehicles, tractors and mowers and have done so for many years…but this situation is one that I have never seen before and one I wanted to share.
I HATE ethanol based autogas. Especially for vehicles or equipment that sit for prolonged periods of time… such as tractors, chainsaws, weed eaters, and lawn mowers. Ethanol has created many problems with attracting moisture from the atmosphere into the gas…then having the water settle to the bottom of the tank. I had an 89 bronco with a new galvanized aftermarket tank that water rusted thru the bottom of the tank in less than eight years, creating multiple pin holes that leaked. In the past, I would always install shut off valves in the fuel lines and run the float bowls dry on my riding mowers after using, only to have water collect in the bottom of the plastic gas tanks requiring that the tanks be drained every spring. Often the ethanol would attack the rubber O-rings, gaskets and seals requiring replacement as needed every 3-4 years.
With three mowers, two working tractors, two weed eaters, and five chainsaws…it was becoming a genuine PITA to constantly have to do more than routine maintenance. I converted to lithium battery powered chainsaws, tree trimmers and weed eaters but the mowers were switched to 91 octane ethanol free gas. After draining the fuel lines, filters and gas tanks, of any ethanol blended gas, and switching to ethanol free gas…I thought that would help resolve the ethanol fuel issues for good. It did not.
When trying to start the Cub riding mower in Farmington two days ago…I could not get it to fire. It would crank easily…but would not start.
I checked the ignition first…plug was good, CDI magnet air gap was set to minimum tolerance and ignition tester showed a healthy spark.
Checked for fuel at the carb by pulling the fuel hose…no gas.
Checked the crank pressure actuated fuel pump and it was working properly.
Checked the fuel line between the carb to fuel pump to fuel filter…and all lines were clear.
Finally when I checked the fuel line from the tank to the fuel filter…it was plugged solid. Attempting to blow air in the line met with total resistance. This fuel line is about 4 ft long and snakes from under the rear plastic fuel tank over the transaxle, under the frame, along the frame rail, through an access hole in the frame, under the steering sector, up behind the engine and finally to the fuel filter. It is a PITA to replace and wire tie back securely. I replaced the line four years ago after it was damaged by a deck v-belt…with generic automotive fuel hose purchased from a farm supply. So…rather than replace it I disconnected both ends and forced 80 psi of compressed air through the line to clear it. Surprisingly there was water in the line…along with small bits of rubber. However not enough debris came out of the hose to explain why it was clogged so badly. But…compressed air was getting through…so I assumed fuel could as well.
Once I had compressed air flowing through the line I reconnected the fuel line at the tank and fuel filter. Put everything back together expecting the engine to fire right up…and NO CHANGE..!
I pulled the gas line back off again and tried to blow through the line…and it was still plugged, even though I had just successfully run 80 psi of air through the line. I was baffled. The line was ¼” I.D and I had a dowel rod that was 3/16” in diameter. When I tried to run the dowel through the line it would go in about 1 inch and stop. This occurred from either end. The line was plugged tight. Then I split a portion of the line lengthwise and found the problem. Even though I had been running ethanol free gas last summer, the ethanol I had used the previous three years had attacked the rubber hose and caused it to swell shut. In some sections the interior of the hose allowed flakes of rubber to separate into the fuel. To be on the safe side... I then pulled the carb, drained and cleaned the float bowl and replaced the fuel filter.
Replacing the fuel line with a high-quality Honda brand fuel hose I use on my motorcycles solved the problem and the engine started right up.
Then I recalled that last summer I had a couple of issues with hard starting and running lean with popping in the exhaust…an indication of a lean mixture or leaking valve. But…it was sporadic. It would occur briefly…then go away. Apparently, the hose restriction was reducing fuel flow even last year causing the engine to periodically lean out. Hopefully I haven’t burned a valve or damaged the piston…but it appears I got lucky. So far it is running normally.
The moral of this account is to avoid ethanol-blended fuel in any equipment or vehicles not specifically authorized to use ethanol. And even if they are…if you replace any fuel lines or fuel components that are gasoline rated…they may NOT be rated for ethanol. I would suggest only using a quality fuel hose that is rated specifically for ethanol.
Or…simply avoiding ethanol entirely on all your equipment that is used seasonally.
Last edited:
