The annual Z425 no start.

mg8t7gn

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Once again, it does not start. If I spray fuel into the air filter it starts and run as long as I spray fuel. This tells me ignition is ok, but no fuel delivery. 2 questions: how do I check the fuel pump, or just replace it? I have adequate fuel supply to the pump inlet and the vacuum hose is new. I here the fuel shut off solenoid clicking as I turn the ignition switch on and off. Is there a way to make it so it never closes off? i do have a fuel cut off valve in the hose from the tank to the pump. Thanks. I'll stick to Corvettes.......................
 

Born2Mow

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Some ideas....
  • Your mower does have a vacuum operated fuel pump. The diaphragm in these will give up. Some of the pumps allow diaphragm replacement, others you replace the whole unit.
  • Your root problem may be associated with stale ethanol fuel being left in the carb over the winter. A varnish-like coating forms on float bowl parts, including the inside of the jets. This can completely close off the slow-speed jet... which supplies the fuel for starting. When this happens the float bowl can be full, but the engine will be getting zero fuel.
  • And you could have water from washing or condensation in the float bowl. All it takes to stop a mower engine is about 1 teaspoon of water. Since water is heavier, it sinks to the bottom of the float bowl where it will completely block the flow of gasoline into the jets.

CCKJPB7.png

This guy has both the water and the brown varnish

Hope this helps.
 
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bertsmobile1

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Pull the fuel line off at the carburettor and crank the engine .
Fuel should pump out .
Put it back on and remove the carb solenoid , check it is retracting fully .
Put some thing under the carb to catch what comes out .
check for water, white jelly or foul brown fuel.
Remove the float bowl crank the engine you should see the fuel pouring out .
If all this checks out then off with the carb & give it a good clean
 
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mg8t7gn

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Thanks all. All ! got done today was pulling off the fuel hose and cranking. Fuel pumped out. Started raining so I am done for today. To check the fuel solenoid, remove it and cycle the ignition switch on and off and watch the pintle move? I can here it but have not visually verified it.
 

Born2Mow

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An
...was pulling off the fuel hose and cranking. Fuel pumped out.
Some ideas...
  • How old is the oldest fuel in the tank ?
  • Did the mower sit over the winter with fuel in the tank ?
  • Don't be too quick to call that stuff "fuel". Ethanol does NOT stay in solution with gasoline. It has to be agitated or shaken regularly. After a dozen weeks of storage your engine could get a big gulp of 15% or more of Ethanol, which your mower engine cannot burn. If that was the case, then the engine would stop, even though it looks like the fuel pump is delivering plenty of "gasoline". It may simply be pumping a liquid which the engine cannot burn.
Hope this helps.
 

mg8t7gn

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Born, guilty on all 3. I'm thinking of a steady diet of Sunoco GT 98 octane unleaded. I guess a carb rebuild is in my future.
 

xray man

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Born, guilty on all 3. I'm thinking of a steady diet of Sunoco GT 98 octane unleaded. I guess a carb rebuild is in my future.
I would try my best to find the non-ethanol fuel if possible. I don't think octane will matter. I've used non-ethanol "regular" 87 octane in my 4-stroke and 2-stroke equipment the past couple of years and haven't had any fuel related troubles with anything. I used to have to get carb. kits or at least a diaphragm for the 2-strokes every year. And had to spend some extra time waking up the 4-strokes.
Non-ethanol made a big difference.
Run em dry when the season ends. Fresh stuff the next.
 

Born2Mow

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I would try my best to find the non-ethanol fuel if possible. I don't think octane will matter. I've used non-ethanol "regular" 87 octane in my 4-stroke and 2-stroke equipment the past couple of years and haven't had any fuel related troubles with anything. I used to have to get carb. kits or at least a diaphragm for the 2-strokes every year. And had to spend some extra time waking up the 4-strokes.
Non-ethanol made a big difference.
Run em dry when the season ends. Fresh stuff the next.
More thoughts...
  • Octane is for acceleration. Since most mowers run at a constant engine speed, a higher grade of fuel will mean very little.
  • The only place more expensive fuel would help is with the fuel cleaners and conditioners found in major brands like Shell and Chevron in their premium fuels. Those cleaners DO work. BUT... you can add the same features to your "regular" grades by adding any number of fuel additive "stabilizers" and "cleaners".
Run 'em dry is the best advice ever !!!
 

mg8t7gn

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There isn't any ethanol free stations near me. Sunoco GT is what I use in my snowblower, Grand National, and 427 Corvette- with some 110 leaded added in. Octane is for knock suppression and since it's readily available at $8 a gallon, which is a lot less than True Fuel.
 

Born2Mow

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Look for a bottle of StarTron at your hardware, boat store, small engine shop, Lowe's, Home Depot... any place that sells or services small engines. This stuff cleans AND stabilizes. Add about 1/2 oz to your main 5 gal fuel can. In that way it works its way into all your small engines.

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It's an 8oz bottle, so you can see that at that rate 1 bottle is good for well over a year. It's really economical for the home owner. I started on this stuff over 10 years ago and I've had zero issues ever since... and ALL my yard equipment is gasoline engine driven.

Hope this helps.
 
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