Kawasaki FR651V Runs then dies randomly

[Josh01010]

I have a Toro TimeCutterZ with a FR651V engine. (circa 2010). This season it has been plagued with stalling issues. When cold it will fire right up with choke out, push in and runs smooth. At times it may run for 15-20 minutes before it dies. It will usually restart just fine but will die quickly with light load on engine (PTO on/off, driving). Sometimes pulling the choke will keep it running, but no power. It seems to get caught in cycle of revving/bogging, you can see the governor opening/closing the carb.

I have replaced Plugs, Coils, Fuel Pump, Carburetor, Fuel Filter. At this point I'm at a loss. Plugs do get a little dirty, but I think that's due to the stalling issue and not the cause. I checked the valve lash and was a little out on one cylinder (exhaust), adjusted and no difference.

Digging around on this forum I may try the 'alternate' fuel tank option to rule out any funny business there.

 

[bertsmobile1]

Yes do that
!3 years is more than enough time to collect enough trash to plug the fuel tank outlet
And your problem has those symptoms

 

[Josh01010]

I rigged up a small fuel tank with some odds and ends around the house:
16oz vitamin bottle, some spare fuel line and shutoff valve, couple hose clamps and a metal valve stem.

I successfully ran three 'tanks' down without any stalling issues, about 40 minutes total. Time to see what's going on with the fuel system.

 

[MParr]

I rigged up a small fuel tank with some odds and ends around the house:
16oz vitamin bottle, some spare fuel line and shutoff valve, couple hose clamps and a metal valve stem.

I successfully ran three 'tanks' down without any stalling issues, about 40 minutes total. Time to see what's going on with the fuel system.

Sounds like trash in the fuel tank and/or line running from the tank to the fuel filter. Check for vent line blocks too. You would be surprised what mud daubers can do.

 

[bertsmobile1]

I rigged up a small fuel tank with some odds and ends around the house:
16oz vitamin bottle, some spare fuel line and shutoff valve, couple hose clamps and a metal valve stem.

I successfully ran three 'tanks' down without any stalling issues, about 40 minutes total. Time to see what's going on with the fuel system.

Well done 10 out of 10 for ingenuity
So now you either have trash in the fuel tank or failed fuel lines
There is a lot of cheap fuel line out there that is neoprene lined .
neoprene will soften & turn to jelly when exposed to fuel so clog the fuel line
Then there is defective fuel line made from the right material where the inner liner is not properly bonded to the outer so again blocks off the fuel line
Damage done by you pushing the fuel line on, so always use a little rubber grease when fitting fuel line .

Cleaning out fuel tanks is a PIA but if you have a good compressor then after emptying and allowing the tank to dry out fully you can remove the fuel cap and blow back through the outlet tube for a long time
A bit of strong wire & a micro fibre cloth wiped around the inside can go a long way to cleaning the tank out .

If you decide to remove the tank, be warned it is a big job
You have to raise the rear body panel near a foot to get it out and to do that you need to loosen the dash tower so it can rise about 1"
If you don't do that there is 99% chance you wil end up bending the foot boards which will make using the mower very uncomfortable.

 

[MParr]

Delete

 

[Josh01010]

The gas tank removal was actually pretty straight forward, remove 4 screws from control panel and move aside, remove the right-side pod (3 screws), clip the zip tie retainer and wiggle it out. Dumped the gas through funnel line with coffee filters into empty gas can. Surprisingly clean except for a few chunks of rubber from the pickup tube that had cracked. Fuel line inspection reveals no blockages or signs of decay. I suspect that the gas may be getting fouled due to the cracked plug exacerbated by the wet weather and humidity here in the northeast.

Working theories in order of likelihood to be valid:
Bad gas: humidity and cracked plug leading to condensation/water in the tank. Replacing the plug (on-order) and fresh gas. No non-ethanol stations near me so keeping the tank full a good option to reduce the effect. Also the cracked plug is a safety issue if you overfill your tank or operate on an angle (uphill especially).

Bad fuel pump/weak flow: I don't know a lot of how the pump works other than pressure from the crankcase?? that drives the impeller which sucks the gas from the tank and pushes to the carburetor. With my hillbilly setup, I'm going to run the engine, then put the line to the pump in a small container with gas and pump it back into the gas can and see how well it works. It's a new pump so I'm think could be weak/inconsistent pressure from the crank case. The hose to the pump looks good but have not had a chance to remove to inspect it more closely.

Fluke: The good run last night maybe was not a valid test meaning something else is going on. The temperature was low 70's and no sun. Most of my issues were in the day, 80+ and sunny/humid. Could be an overheat issue. I need to try my current setup again during the heat of the day.

I will say, the mower ran quite well last night and powered through the weeds and grass that had built up out back without a whimper, so I think i'm on to something.

Lastly, any wisdom as to what a faulty Diode would do? How would you know it's failing? My understanding it's a safety feature for the PTO clutch and would not have any operational impact?

 

[MParr]

Did you change out the pickup line?

 

[Josh01010]

Did you change out the pickup line?

No, the only issue I saw with it was the rubber bushing that holds it in the tank, that was cracked and not holding it firmly. That's on order from Amazon.

 

[volt]

I had similar problem. I found that the shutoff valve below gas tank was clogged. I removed fuel shut off valve and when I blew into it I could tell it was clogged. I had also removed fuel tank because I thought that it would be easier to remove and replace fuel shut off valve by removing Tank. I emptied tank so that got cleaned.