Ford 800 fuel issue/stalls when hot

Brad Shinkle · Jul 28, 2013

My Ford 800 start easily but seems to encounter some sort of fuel vapor lock. While mowing trails recently with air temperature in mid 50's, and water temperature in the green, the engine begins to experience high and low revs without any change in throtle setting. Gradually the engine looses power and eventually simply stalls completely. Given an hour or so to cool down the engine fires up normally.

Do others experience this problem? Any suggestions for a fix would be appreciated.

Thanks

old · Jul 28, 2013

6 or 12 volts can make a big difference as to the problem. When it dies the first thing to check is if you have a good blue white spark. Poor spark says a coil going bad. Good spark says boiling fuel in the tank or vapor lock due to bad tank vent. Also check for good fuel flow out the carb drain plug when it dies. Also carefully remove the gas cap and make sure it does not have a suction or boiling gas

Jimmyjack · Jul 28, 2013

Fairly typical of this series if the gas line goes behind the manifold and over the engine. Ethanol in the gas makes it boil at lower temps. Can help situation by running gas line around the engine in front works best. Use non ethanol gas. Will help the vapor locking if it pops and backfires when hot. Check comments in the archives.

Dean · Jul 29, 2013

It's not vapor lock and it's not fuel line routing.

Verify that the ignition is spot on and fuel flowpast the sediment bulb is adequate..

Dean

GVSII · Jul 29, 2013

(quoted from post at 20:05:06 07/28/13) Fairly typical of this series if the gas line goes behind the manifold and over the engine. Ethanol in the gas makes it boil at lower temps. Can help situation by running gas line around the engine in front works best. Use non ethanol gas. Will help the vapor locking if it pops and backfires when hot. Check comments in the archives.

First: Not typical.Second :Routing the fuel line around the front of the engine will do two things for you-make the line longer and subject it to more vibration. The as delivered fuel setup DOES NOT vapor lock!

Texasmark1 · Aug 2, 2013

Also is there a sheet metal heat shield between the engine/muffler and the tank? If not there should be to help and keep especially muffler heat off the tank.

Mark

showcrop · Aug 2, 2013

(quoted from post at 14:50:39 07/29/13)

(quoted from post at 20:05:06 07/28/13) Fairly typical of this series if the gas line goes behind the manifold and over the engine. Ethanol in the gas makes it boil at lower temps. Can help situation by running gas line around the engine in front works best. Use non ethanol gas. Will help the vapor locking if it pops and backfires when hot. Check comments in the archives.

Click to expand...

First: Not typical.Second :Routing the fuel line around the front of the engine will do two things for you-make the line longer and subject it to more vibration. The as delivered fuel setup DOES NOT vapor lock!

GVSII; Personally, I don't believe in vapor lock and despite some hard work on hot days with ethanol gas neither of my old 4 cylinders have had this sort of problem. I do recognize however that ethanol gas has a lower boiling point so I don't dispute that some people under the right conditions could have the problem. Back in the day my uncle tried all kinds of cures to try to prevent gas from boiling in the tank of his 860 while chopping corn. I am not sure that your use of capitals really makes it impossible for vapor lock to happen.

GVSII · Aug 2, 2013

(quoted from post at 06:38:05 08/02/13)

(quoted from post at 14:50:39 07/29/13)

(quoted from post at 20:05:06 07/28/13) Fairly typical of this series if the gas line goes behind the manifold and over the engine. Ethanol in the gas makes it boil at lower temps. Can help situation by running gas line around the engine in front works best. Use non ethanol gas. Will help the vapor locking if it pops and backfires when hot. Check comments in the archives.

Click to expand...

First: Not typical.Second :Routing the fuel line around the front of the engine will do two things for you-make the line longer and subject it to more vibration. The as delivered fuel setup DOES NOT vapor lock!

Click to expand...

GVSII; Personally, I don't believe in vapor lock and despite some hard work on hot days with ethanol gas neither of my old 4 cylinders have had this sort of problem. I do recognize however that ethanol gas has a lower boiling point so I don't dispute that some people under the right conditions could have the problem. Back in the day my uncle tried all kinds of cures to try to prevent gas from boiling in the tank of his 860 while chopping corn. I am not sure that your use of capitals really makes it impossible for vapor lock to happen.

Showcrop,I'm useing the same ethonal gas that most of the U.S. is useing-no vapor lock.Should any vapor form in the fuel line where is it going to go? It's not going to go DOWN to the carb.It's going to go UP to the fuel tank.The as delivered fuel set up does not vapor lock and never has. I don't dispute that some are haveing a problem but the problem isn't V/L.

jeff pk · Aug 2, 2013

I had that problem and it turned out to be a leaking exhaust manifold gasket. It got worse when it warmed up and then started to surge---first thought it was boiling fuel etc.

Hobo,NC · Aug 3, 2013

I had a 850 that the fuel would stop flowing at any given time time,,, Its EZ to check remove the drain plug in the bottom of the carb... If fuel flows fuel is not your issue... Use a spark checker and check spark...

DollarBill · Aug 3, 2013

Checked the point setting lately? When mine does as you describe the points have closed up on it. Re-gap the points and it's back to work.

One other very simple thing to check is making sure the gas tank is venting properly. Does it hiss when you loosen the cap?

Ford 800 fuel issue/stalls when hot

Brad Shinkle

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old

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Jimmyjack

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Dean

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GVSII

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Texasmark1

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showcrop

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GVSII

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jeff pk

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Hobo,NC

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DollarBill

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