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Cub cadet runs for 5 minutes and dies


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08-06-07, 10:25 PM   #1  
Cub cadet runs for 5 minutes and dies

I have been battling this problem for weeks and at my wits end. I thought that I had a heat related problem but am not sure now. This is a Cub Cadet 1525 with a Kawasaki FH380v-as12 15 hp engine with a Walbro LMF carb. The service manual that I purchased from Kawasaki was pretty light in the carberator area, all over as a matter of fact. It did warn against poking wires through the orifices or using harsh chemicals because plastic plugs were used and could easily be damaged. After messing with the carb settings and attempting to spray the carb with cleaner and blow it out using compressed air I decided to put the machine in the shop. $130 later I picked up the machine and mowed for 2 hours before it quit. Consulting with the mechanic, she suggested that I had picked up some dirt in the carb and blew me off. More shade tree mechanicing on my part with no effect caused me to go to another shop. Another $80 ended in the same result. The machine will run for 5 minutes under load and begin to lope/surge then stall. Wait a few minutes and restart but fail after just a minute. I have replaced the fuel pump, filter, fuel line, both ignition coils, both spark plugs and I wrapped the fuel line with aluminum foil thinking vapor lock. Where do you suggest that I go from here. It's embarassing to keep borrowing the neighbor's machine. Oh yes, I added a water consuming additive to the gas tank just in case.


Last edited by jderk; 08-06-07 at 10:28 PM. Reason: another fact
 
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msidan's Avatar
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08-07-07, 05:55 AM   #2  
I never worked on a Kawasaki, but are you sure the gas cap is venting? Also, immediately after it dies the next time, check for spark.

 
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08-07-07, 06:50 PM   #3  
Did you check your fuel flow from the tank hose to a gas can? Sounds like a fuel cap, plugged tank vent or plugged fuel pick up from the tank. When it stops take the fuel cap off and see if it runs longer. If not look at what amount of fuel flows out of the hose. How full is the fuel tank when it first stops? A full fuel tank with a bad vent whether it is the cap or other vent will creat a vacuum in the tank faster than a half full tank. If you have some junk in the bottom of the fuel tank that is getting into the fuel pickup, you will get a slow fuel flow when you removed the line. Hope this gives you a start.

Does the engine have a fuel pump on the side of the upper shroud? Kawasaki is very sensative with the vacuum fuel pumps if there is a leaking gasket. Try the other and if it has a pump let me know.


Last edited by CAMINO KID; 08-07-07 at 06:51 PM. Reason: additional items
 
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08-07-07, 08:00 PM   #4  
Longshot here but I have seen it more than once. Did you check inside your tank to see if the aluminum cone that attaches inside the gas cap is in there? When they dofall in they can float around block the gas, then when machine dies it floats away from screen and can be back in minutes or an hour. Reaching here. Good luck

 
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08-07-07, 08:53 PM   #5  
Tried that.

This engine has a diaphragm type fuel pump which I have replaced. The gas flows freely from the tank and appears clean. I replaced the fuel line and have a new filter. I have removed the gas cap thinking about a possible inoperative vent. The spark appears intact but I have replaced both ignition coils and spark plugs. The fuel pump delivers fuel at cranking speed but I have no way to tell how much it gives at running speed though I guess it would be good. If there was a faulty component it should bum out off the go but this runs until it gets heated up.One thought was that one of the ignition coils was shorting to ground after heating but I've replaced them. Vapor lock was the first guess but this is the original design and I insulated the fuel line from the fuel pump to the carb using aluminum foil. I thought about water in the fuel and administered Heet, a dessicant for gasoline. I wondered about the carb to intake manifold gasket leaking after heating and sealed it off with rubber tape. After she heats up and has been running OK under load as it begins to fail the engine lopes as if starving for fuel. Applying the choke will give me a few more seconds but without load power. Wait a minute or 2 and restart but without load power just engine function. Cool down completely and I get another 5 minutes. The engine is clean and air passages are unblocked. The fan is intact and moving air. Ideas?

 
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08-07-07, 10:35 PM   #6  
I agree that you have a fuel starvation issue. Take the bowl off and crank the engine with a cup under the carb to catch the gas. View how much gas is pumping into the carb through the inlet needle and make sure it is a constant flow, not just a trickle.


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08-08-07, 07:11 PM   #7  
Another possibility would be an air leak in or around the intake manifold mounts to cylinder. Also I would check valve lash and make sure there is sufficient clearance.

 
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08-08-07, 07:48 PM   #8  
Just for reference, can someone explain to me what the wrapping of the fuel line in tinfoil serves?

Thanks

To the OP: I suggest a fuel starvation issue as well. However, it seems you've covered a lot of bases (which is good for a DIYer). However, since you have been to at least 2 different shops, could you not convince them to hang around as you "re-introduced" the problem? Also, can you reproduce the problem at high-speed idle? I just think something like an obstruction in the line, or a vapor-lock. But, I have never been introduced to the tinfoil method and am interested.

I really don't know, but then again I'm not a complete expert like some of the others here. Sure, I had Small Gas Engines in HS, and at the University. Still cannot beat the day to day experiences you get in a shop setting.

I will say this, those inlets you were speaking of cleaning (with the plastic stuff), if there is holes on the nut ( one through the threads, and out the top end of the nut) that holds the bowl onto the carb, CHECK and CLEAN that nut that holds the bolt on with whatever wire you can push through there. Maybe it is getting some trash in there as you run it. I owe cheese for that on one of my own projects. But, mine wouldn't start at all. Without "primin' her over and over). Thanks again cheese, still working like a champ.

Anyway, good luck. These things can be frustrating at times, for sure.

Edit: Here is a picture showing the nut I am referring to. It's in the 2nd column, 2nd picture. 1/2 down the page. http://cgi.ebay.com/Kawasaki-15hp-FH430V-Walbro-LMF-Carburetor_W0QQitemZ330145972596QQcmdZViewItem


Last edited by Heterman; 08-08-07 at 07:54 PM. Reason: Added Ebay picture link
 
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08-09-07, 07:02 PM   #9  
I have run into this problem on several Kawasaki engines the last two years on Toro Mowers. There is a leaking gasket, either the valve covers or the upper crankcase vent cover under the flywheel. You do not see any oil leakage as it is a vacuum leak and is drawing outside air into the crankcase. The diaphram fuel pump uses the vacuum created in the crankcase to pulse the fuel pump. I found this by attaching a vacuum guage to the hose from the crankcase or valve cover on the fuel pump and ran the engine on an external fuel supply direct to the carb. There should have been a flucuation in the guage but had nothing. I do not have the complete breakdown of your engine at my home and will not be going into the shop for several weeks due to an emergency surgery or I could get the part numbers for you. I ended up on both of these engines replacing the valve cover gasket and the upper crankcase gasket under the flywheel to solve the problem. I have two 20 hp Kawasaki engines running my JD tractor and mower but both of them have machinacial fuel pumps.

 
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08-09-07, 07:43 PM   #10  
I found this site that will give you a picture of the engine and parts.
http://www.messicks.com/cubparts.aspx?ID=2482&model=1525

look at the engine block illustration. You will need to remove the flywheel to get to the breather gasket part # KM-11061-7008. I used the widest puller that Snap-on had and also use a large "c" clamp to hold the fingers of the clamp on the flywheel. I tightened the puller bolt to the crankshaft and hit the end of the puller bolt to get the flywheel to pop loose. I used permatex #2 non hardening on both sides of the gasket and torqued the bolts on the cover. The valve cover gaskets are KM-11060-7001.

I spend several hours on the first one of these and that was after my boss had tried everything for several days before giving it to me. The last time I was putting this in they timed me out so I did not step you through the repair as before.

 
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08-09-07, 07:48 PM   #11  
Camino...Nice info. I'll tuck that in my mental files so if I run into this scenario, maybe I'll remember this.

You said you they timed you out. You mean this site timed you out, and wouldn't let you post because it thought you took too long to do it? I didn't know that this site used that practice.


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08-10-07, 01:43 PM   #12  
Tinfoil

In days gone by, some automobiles were designed so that tha metal fuel line would pass close by the exhaust manifold or some other heat producer. Once an exhaust leak would occur, ever so slightly, the gasoline could vaporize inside the line before reaching the carb. Wrapping aluminum foil around the fuel line would provide enough insulation to prevent the vapor lock and subsequent stalling.
Posted By: Heterman Just for reference, can someone explain to me what the wrapping of the fuel line in tinfoil serves?

Thanks

To the OP: I suggest a fuel starvation issue as well. However, it seems you've covered a lot of bases (which is good for a DIYer). However, since you have been to at least 2 different shops, could you not convince them to hang around as you "re-introduced" the problem? Also, can you reproduce the problem at high-speed idle? I just think something like an obstruction in the line, or a vapor-lock. But, I have never been introduced to the tinfoil method and am interested.

I really don't know, but then again I'm not a complete expert like some of the others here. Sure, I had Small Gas Engines in HS, and at the University. Still cannot beat the day to day experiences you get in a shop setting.

I will say this, those inlets you were speaking of cleaning (with the plastic stuff), if there is holes on the nut ( one through the threads, and out the top end of the nut) that holds the bowl onto the carb, CHECK and CLEAN that nut that holds the bolt on with whatever wire you can push through there. Maybe it is getting some trash in there as you run it. I owe cheese for that on one of my own projects. But, mine wouldn't start at all. Without "primin' her over and over). Thanks again cheese, still working like a champ.

Anyway, good luck. These things can be frustrating at times, for sure.

Edit: Here is a picture showing the nut I am referring to. It's in the 2nd column, 2nd picture. 1/2 down the page. http://cgi.ebay.com/Kawasaki-15hp-FH430V-Walbro-LMF-Carburetor_W0QQitemZ330145972596QQcmdZViewItem

 
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08-16-07, 08:09 PM   #13  
Best shot I've seen so far

Boy that makes a ton of sense. If I lose suction on that fuel pump diaphragm then when the carb bowl runs down it's curtains. I'll try the valve cover gasket 1st. Don't want to pull the flywheel if I don't have to. Thanks Camino Kid for the help. I'll let you know what happens. I'd like to use one of those happy face charaters in my reply. Thanks to everybody for the help.

 
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08-29-07, 11:05 PM   #14  
Fuel pump pulls constant vacuum

Well no smiley face yet. I connected a vacuum gauge and found a constant 1 to 2 ". That negates the lost vacuum thought. The tank is just a few inches lower than the pump. I am going to pull the carb apart and start from scratch. I do not recommend the Kawasaki engine because the parts are not easy to come by. While the engine may be good the service from Kawasaki and its dealers is lacking. Go with the Kohler if you want a Cub Cadet.

 
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08-30-07, 07:31 PM   #15  
Is there still gas in the carb bowl when it shuts down? Did you check fuel flow into the carb with the bowl removed?

I like Kohler, but I would'nt choose a Kohler over a Kawasaki.


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09-28-07, 08:49 PM   #16  
Alright! I have located the owner manual which tells me that all Cub Cadets of my model have a fuel shutoff solenoid that cuts the gas off on shutdown in order to prevent backfire. It seems likely that this could be the problem. After runnung for a short while the solenoid windings heat up and separate losing magnetism. The spring loaded valve slams shut. The fuel in the carb bowl allows it to run for a few seconds and then kaput. My current problem is that none of the websites that show parts diagrams/listings mention a fuel shutoff solenoid. The owner manual gives a process for extrication of the part but it is very involved. I cannot see it or feel it and as such I hate to get that far into it only to discover that no such part exists on this machine. Does anyone know how I can get the part # for the solenoid without actually having it in hand? If I have the part # then I can reference it in the Cub Cadet database online. Word phrase searches don't work. This machine has been down for the entire mowing season. The Cub Cadet parts network has been of no help. I'm thinking that I should have bought a machine from Sears for half the cost and where I can always get parts.

 
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09-29-07, 12:22 AM   #17  
Your thoughts are reasonable...if it is equipped with a shutoff solenoid, it could feasably be the problem. I've never seen one fail in this manner, but this isn't an ordinary problem you have either. Generally, the shutoff solenoid is screwed into the carb under the bowl, and is actually what holds the bowl onto the carb.


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09-29-07, 08:18 AM   #18  
I don't think you have a fuel solenoid on yours. If so there should be one or two wires going to the carb someplace. Usually they are as cheese said, screwed into the bottom of the bowl and actually hold the bowl on. Some are in the carb body themselves, but have not seen a Walbro like that.

I do think most of the common or simple things have been covered and it may be time for some deeper inspection. I have seen things such as rocker arms hanging or coming loose, ball bearing check balls loosen and suck into the cylinder and bounce around acting as a fouled plug...etc.

If you absolutely want to eliminate a fuel delivery problem, you could rig up an external gravity feed fuel supply. Use a small gas can and install a bulkhead fitting to run a fuel hose to the carb. Strap the fuel can to the hood and route the hose so as not to pinch it.

Otherwise I think it may be time to pull the valve covers and possibly the heads for further inspection.

 
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09-29-07, 08:25 AM   #19  
My lookup indicates that there is no fuel solenoid but that doesn't mean that there isn't, in fact, one installed. If yours does then you'll see a wire, maybe two, going to the carburetor bowl area. Do you see such?

 
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10-01-07, 05:46 PM   #20  
The 1-2 inch of steady vaccum is not good. It should fluctuate and be up to 5 inches or more. If you pull the output fuel line off the pump when it quits you should not see any fuel being pumped to the carb. Like I said in my previous post I had to train my boss on this and I got it from the Kawasaki folks when I had a simular problem with two Kawasaki engines.

 
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05-29-10, 11:16 PM   #21  
The problem turned out to be bio fuel.

Sorry that I haven't responded sooner but here is the answer. The fuel tank cap on this model is pretty big. This allows grandchildren to insert leaves into the tank. The leaves will gravitate to the current created by the fuel pump. The engine then starves for fuel and dies. When the fuel pump current ceases to attract the leaves they float away to await a new ride. This may take several minutes to return to the scene of the crime. The leaves were removed by a gargantuan friend who simply dumped the machine over and plucked out the offending bio fuel.
Thanks to all of the helpers for my problem. There were many good suggestions.Beer 4U2

 
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