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I own a hustler mini z with the kawasaki engine. It has started dying after about 15-20 of use. I can choke it and it will restart and run chokes, but when I hed back to my shop it will try to dye every five seconds or so. If I stop my forward progress it will start running better five seconds and start trying to die again. I can let it cool down for 30 minutes and she'll give me another 15 mins. I have changed the air filter, fuel filter twice, cleabed fuel cap, drained and cleaned fuel tanks, new fuel lines, new fuel pump, and cleaned carb. I have noticed this morning the fuel filter was full of fuel, but when it started it's new routine it barely had any in it. If it starts with the choke on I would think it would be a fuel issue, but I would think I covered everything fuel related. I would greatly appreciate advice from someone with more knowledge.
thanks in advance.

Can anyone help?

giggs said:

Can anyone help?

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I'll take a stab at it. I'll share some of my personal experiences with you and maybe one of the reasons I found causing fuel starvation is the same reason you are experiencing fuel starvation or so it seems. I found a large seed of some type stuck in the fuel line elbow and after clearing the obstruction the mower ran fine. I also found the seat in the carburetor swelled to the point that it would let enough fuel past to idle the engine but when the engine was put under load it would act the same as you are experiencing. I also found that when people say they cleaned the carburetor it actually turned out that they took a can of carburetor cleaner and sprayed the outside of the carburetor and swore up and down that they cleaned the HE!! out of the carburetor. Go figure. Just because you say you cleaned the carburetor it doesn't mean you cleaned the whole carburetor or cleaned it properly. I don't know how much you know about cleaning carburetors so I have to question your procedure.

How about float level, did you check that? Did you check fuel pump outlet? Does your fuel pump have an impulse line? If so, did you check the impulse line? I have seen where the impulse line collapsed or had a hole in it preventing the fuel pump from pumping enough fuel when the engine was under load. You obviously replaced a lot of parts but none of them fixed your problem. What have you actually tested? What were the results?

You are the eyes, ears and fingers in the situation and all we have to go by is what you told us in your first post. How about some engine numbers?

I've given you some possible causes to the problem you are experiencing with your mower engine and it's entirely possible that none of the causes I mentioned will correct you particular problem but we have to start somewhere. From what you described it sounds like fuel starvation but did you check for spark when the engine dies? The coil could be on its way out and if it is we are on a wild goose chase looking at the fuel system.

Perform the checks/tests I mentioned and report back with your findings.

I have taken the carb completely apart, soaked in carb cleaner, cleaned each orface, and reasembled.
I am a hobbiest machanic, but I have rebuilt a engime or two. All lines from the tanks to the carb have been replaced, except for the small line inside the tanks, but I did blow them out. I have twin tanks that did run to a valve, but I replaced the valve with a t so the pump pulls from both tanks. I have tested spark when it's acting up and both plugs are receiving sparks. I just eliminated the fuel shut off solenoid, so no problem there. I also cleaned all fins and blades. Oh, the engine is a kaw FH 580V.
I am very appreciative of your help.

giggs said:

I have taken the carb completely apart, soaked in carb cleaner, cleaned each orface, and reasembled.
I am a hobbiest machanic, but I have rebuilt a engime or two. All lines from the tanks to the carb have been replaced, except for the small line inside the tanks, but I did blow them out. I have twin tanks that did run to a valve, but I replaced the valve with a t so the pump pulls from both tanks. I have tested spark when it's acting up and both plugs are receiving sparks. I just eliminated the fuel shut off solenoid, so no problem there. I also cleaned all fins and blades. Oh, the engine is a kaw FH 580V.
I am very appreciative of your help.

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How about the rest of the recommendations I made? Make sure to answer all the questions I asked in my previous post, thank you. I will keep thinking on this one and hopefully help get the problem solved.

Fuel pump outlet is good. Not sure what a impulse line is??? What has me stumped is after it cools if you look in the clear fuel filter, it's 3/4 full. When it starts acting up it is 99% empty. This has me puzzled. The line going from the valve cover to the fuel pump??? I'm just stumped.

giggs said:

Fuel pump outlet is good. Not sure what a impulse line is??? What has me stumped is after it cools if you look in the clear fuel filter, it's 3/4 full. When it starts acting up it is 99% empty. This has me puzzled. The line going from the valve cover to the fuel pump??? I'm just stumped.

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Yes, the line going from the pump to the valve cover is the impulse line and this is what "powers" your fuel pump. Check the impulse line for any defects.

The fact that the filter is 99% empty when it acts up is most likely your problem and you will have to find out where the fuel is being restricted. Check the fuel pump outlet when the problem occurs.

The impulse line was split a little where it mounts to the valve cover. I ordered one online but taped it up for the time being. Recheched and the tape is holding. Could it be something inside the valve cover like a push rod or something?

Doubtful that it's a push rod but anything is possible. Hopefully the split in the impulse line is the cause and the new line will fix it but time will tell. Just an FYI, as the piston moves up and down in the cylinder, the crankcase will be either under a slight vacuum or pressure depending on the position of the piston and this minor pressure difference is what "powers" your fuel pump. If there is a leak in the impulse line there will be less "power" to operate the fuel pump and obviously when the engine is under load is when it needs the most fuel.

Should the line not be the culprit, is it possible to use a electric pump?

I prefer to stay with what the engineers designed and built unless there is a known defect and the manufacturer comes out with a fix for the specific problem.

Carbs typically have an expected input pressure. I am not experienced with the little ones used on lawn equipment ,but it seems an automotive pump ( are there others?) would probably be too much and likely to knock the inlet valve open permanently . Auto pumps run 3 psi and UP. :2cents:

You will have very little 'pressure' in the fuel line to the carb... but you need some so don't abandon the factory fuel pump, it will give you enough without giving too much.
Have you tried running it with the gas caps off... your tank vent system could be plugged and then will not allow fuel to be pulled from the tanks...
also if the fuel line supplying fuel to the pump is getting Hot, it will vapor lock and not be able to pump... :smile:KennyV

You said that you eliminated the fuel shutoff solinoid. Did it run OK after "that" change? The fuel circuit on some of these machines can be tricky. I tried putting in a "T" in an Exmark Z and it wouldn't work. It's been a while, but it had something to do with the fuel return due to the fuel injection on the Kawai's

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"Have you tried running it with the gas caps off... your tank vent system could be plugged and then will not allow fuel to be pulled from the tanks...
also if the fuel line supplying fuel to the pump is getting Hot, it will vapor lock and not be able to pump... :smile:KennyV[/QUOTE]"


Had the same problem with my Husqvarna - loosen the fuel cap - problem solved.