FD501V dies when hot, won't restart

arch252

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17hp liquid cooled twin cylinder. Runs perfect for about 20 minutes then suddenly dies and won't restart until it is cool. I have checked and both coils have good spark just after it dies. I've tried loosened the fuel cap. Newer fuel filter with no debris in it. Does not seem to be a fuel delivery issue to the carb. Any thoughts? Dies. consistently after 20 minutes every time.
 

bertsmobile1

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pair of new plugs
pair of in line spark testers
Can of carb cleaner.

Put the new plugs in and install the spark tester where you can see them easily.
Go mow, the instant it stops spray a VERY SMALL shot of carb cleaner down the carb and crank the engine while watching the spark testers.
IF the testers are flashing the electronics are good
If the engine fires on the carb cleaner then the valves are good which only leaves the fuel supply.
IF it fired the do the same again but before the engine stops give the carb another shop.
If you can keep the engine running like this for 30 sec or so, time to check the entire fuel system, from the carb through to the fuel tank & fuel tank vent.
Pull the fuel line off at the inlet side of the pump loosen the fuel cap and blow back through the fuel line a couple of lung fulls.
Reconnect & try to start the mower, runs fine + obstruction in in the fuel line between the pump & the tank.
ZTR engine eat dust,
For fuel to get out of the tank the dust laden air has to get in.
Add some grass clippings and you have a plug that can block off the fuel supply just enough to be unable to keep up with the engine.
 

arch252

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Thanks Bert, I'll give that a try
 
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Arch............ Fuel lines will act up and bedazzle a lot of people..... Bert gave you some great advice... Fuel lines seem to be good when you blow thru them... They do break down and flap on the inside due to etho in the gas though....

The best way to solve that is spend a few bucks for some new line...... Oh and make sure your outlet nipple is free and clear also.... Junk will float around until it finally gets sucked down into that small bottle necked area ............

Let us know Mon Ami ~!~!
 

arch252

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Ran it until it died, right at 20 minutes. Checked spark and it was good. It started with starter fluid and ran as long as I kept bumping the starter fluid. Definitely a fuel delivery issue. I didn't have time but when it does it again I'm going to remove the fuel line at the carb and see if the fuel pump is still pumping. That should tell.me if the problem is with the carb or from the fuel line to the tank.
 

bertsmobile1

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Definately a fuel supply problem.
So that cuts things down by 1/2
For the test you intend to do you need to time how long it takes to fill a container from the pump cold then time the same container hot.
needs to be about a quart to get a realistic reading.
Times should be exactly the same.
I like to use a temporary fuel tank plugged into the fuel pump when the engine starts to play up.
Problem goes away the blockage is between the pump & tank cap.
Stays the same then pump to main jet venturi is the problem.
When repairing we always try to avoid doing unnecessary dissmantleing cause you can do a a lot more damage for no benefit.
 

arch252

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So I ran it again until it died. Checked fuel flow to the fuel pump and had good flow. Checked the fuel flow from the fuel pump to the carb and it was not pumping at all. I've ordered a new fuel pump. I'll post when I confirm that was the issue. I didn't realize a fuel pump would fail when it gets warm.

I'm going to post an electrical wiring question on a Snapper with a 12hp Briggs when I figure out the best place to post that, any Snapper folks please check that out.
 
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