OK, folks. I did a search here and did not find anything about this, so hopefully I'm not just repeating something you already know.
Most of the country has been switched to E-10, or 10% ethanol.
There are several problems with Ethanol, but the two that affect us mostly are phase separation, and solvent action.
Phase separation occurs when the fuel sits up for a while and/or absorbs enough moisture. The Ethanol will absorb moisture right out of the air. When it gets enough, it will settle out of the gas and form a layer with the water on the bottom of the tank. Once this happens, its fairly permanent. You can't remix it. You have to suck out the old and replace it.
This causes several problems.
The water may rust the tank.
If its deep enough, the pickup will suck a water/alcohol mix into the engine. This can cause hydrolocking, or a real lean burn condition since the alcohol does not have as much calorie output as gas.
If your fuel pickup does stay in the gas, there is another problem. The alcohol is used to increase the octane rating. If the alcohol settles out, the octane of the remaining gas will drop several points. This can cause lots of knocking or pre-ignition damage.
.
If you run your truck daily, the phase separation problem will not be likely. But, if you are running a carb and keep finding sludge or strange trash, in the bowl, or you keep having to change fuel filters, the second part of the problem has grabbed you.
Ethanol is a really good solvent. If your truck is fairly new, the hoses and plastic parts that come in contact with the gas can usually handle the alcohol. If its older, the rubber and plastic might be attacked by it.
But even if its not, if it is over a few years old, there is going to be varnish, sludge, and other things in the fuel system.
Which the ethanol will cheerfully dissolve. And then redeposit them in places you don't want.
A friend of mine has an 85 truck with a carb. Despite two fuel filters, when the E10 first hit, his pretty much quit running. It would run rough at half throttle and above, but you could forget about it idling. I pulled the top of the carb off, and there was a bunch of brown sludge in the bowl.
We cleaned it out, the truck ran great. For about a half day.
Then, same problem, same sludge.
Despite changing both fuel filters twice, we just basically had to pull the carb top off about every other day for a week until all the stuff worked its way out of the tank.
Also, if you happen to have an aftermarket tank made of fiberglass that is over a few years old, the ethanol might just dissolve it.
Its a tossup then as to what happens first. The tank splits or collapses, or the dissolved fiberglass resin sticks your valves or coats your piston rings.
If you are using the gas out regularly, the phase separation problem is not likely. But, if the truck sits up for a while, such as a project truck, one that is being repainted or having a major mod done, the phase separation may occur.
Before E10, if you left the gas in the tank too long, it went stale, and might clogs things up a little, but pretty much would not hurt the engine.
Now, trying to start a truck with old E10 could cause major damage. Depending on how much separation has occurred.
The stuff will phase separate over time, but if it absorbs more than a certain amount of water, it will separate quicker. E10 can hold only about .05% at 60 degrees. This is about 3.8 teaspoons per gallon. If more than that gets in, it can PS immediately.
Also, for you folks in cooler climes, as the temp drops, the amount it can hold drops. Which means your truck might crank fine at 60, and not at 40 or below.
The links below are primarily for boats, but it can still happen to a truck.
http://www.fueltestkit.com/ethanol_engine_precautions.html
This one is selling kits, but has good info too.
http://fuelschool.blogspot.com/2009/02/phase-separation-in-ethanol-blended.html
Sorry for the long post.
J.
Most of the country has been switched to E-10, or 10% ethanol.
There are several problems with Ethanol, but the two that affect us mostly are phase separation, and solvent action.
Phase separation occurs when the fuel sits up for a while and/or absorbs enough moisture. The Ethanol will absorb moisture right out of the air. When it gets enough, it will settle out of the gas and form a layer with the water on the bottom of the tank. Once this happens, its fairly permanent. You can't remix it. You have to suck out the old and replace it.
This causes several problems.
The water may rust the tank.
If its deep enough, the pickup will suck a water/alcohol mix into the engine. This can cause hydrolocking, or a real lean burn condition since the alcohol does not have as much calorie output as gas.
If your fuel pickup does stay in the gas, there is another problem. The alcohol is used to increase the octane rating. If the alcohol settles out, the octane of the remaining gas will drop several points. This can cause lots of knocking or pre-ignition damage.
.
If you run your truck daily, the phase separation problem will not be likely. But, if you are running a carb and keep finding sludge or strange trash, in the bowl, or you keep having to change fuel filters, the second part of the problem has grabbed you.
Ethanol is a really good solvent. If your truck is fairly new, the hoses and plastic parts that come in contact with the gas can usually handle the alcohol. If its older, the rubber and plastic might be attacked by it.
But even if its not, if it is over a few years old, there is going to be varnish, sludge, and other things in the fuel system.
Which the ethanol will cheerfully dissolve. And then redeposit them in places you don't want.
A friend of mine has an 85 truck with a carb. Despite two fuel filters, when the E10 first hit, his pretty much quit running. It would run rough at half throttle and above, but you could forget about it idling. I pulled the top of the carb off, and there was a bunch of brown sludge in the bowl.
We cleaned it out, the truck ran great. For about a half day.
Then, same problem, same sludge.
Despite changing both fuel filters twice, we just basically had to pull the carb top off about every other day for a week until all the stuff worked its way out of the tank.
Also, if you happen to have an aftermarket tank made of fiberglass that is over a few years old, the ethanol might just dissolve it.
Its a tossup then as to what happens first. The tank splits or collapses, or the dissolved fiberglass resin sticks your valves or coats your piston rings.
If you are using the gas out regularly, the phase separation problem is not likely. But, if the truck sits up for a while, such as a project truck, one that is being repainted or having a major mod done, the phase separation may occur.
Before E10, if you left the gas in the tank too long, it went stale, and might clogs things up a little, but pretty much would not hurt the engine.
Now, trying to start a truck with old E10 could cause major damage. Depending on how much separation has occurred.
The stuff will phase separate over time, but if it absorbs more than a certain amount of water, it will separate quicker. E10 can hold only about .05% at 60 degrees. This is about 3.8 teaspoons per gallon. If more than that gets in, it can PS immediately.
Also, for you folks in cooler climes, as the temp drops, the amount it can hold drops. Which means your truck might crank fine at 60, and not at 40 or below.
The links below are primarily for boats, but it can still happen to a truck.
http://www.fueltestkit.com/ethanol_engine_precautions.html
This one is selling kits, but has good info too.
http://fuelschool.blogspot.com/2009/02/phase-separation-in-ethanol-blended.html
Sorry for the long post.
J.
