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Got a 25hp Kawasaki FH721V I can't get to start

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Indiana_Tom

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Discussion starter · #1 ·
Hi all, I have a 25hp Kawasaki FH721V on a 61 inch zero turn mower. I have had it for about 3 years and I bought it new. It has always ran great. I put a float charger on it for a day one time a month in the winter to keep the battery up and start it about every 45 days and let it warm up good. About 2 months ago, it would crank fine but would not start. After I cranked for a long time, it fired and gave one sputter. Some more cranking and it did the same. Working with the choke it backfires several times and it finally started. I let it run till it was full temperature and shut it off. Next time, it did the same thing. It has to be cranked for several minutes and go through some sputtering and backfiring before it will start.

I pulled the gas line going from the fuel pump to the Carb off and cranked the engine and it had a decent flow. I have checked the valves and adjusted then but that made no difference. The choke is closing completely so now I am not sure what to check. When it finally starts it runs great. it just does not want to start with out the crank crank crank cycle.

Help !!!! Any ideas?????
 
#2 ·
Discussion starter · #4 ·
Thanks for the replies. And for the service manual. I went out and checked the spark and it looks good. Then I put the plugs back in and cranked for about 30 seconds. Man when it backfires in my tin barn, it will jar your teeth. :) Then, I pulled one of the plugs and it seemed dry. Maybe it is not getting fuel thru the carb?????? But when it finally starts, it purrs like a kitten. The gas in it was from last fall, late in the year but I have never had it go bad. It is either 10 or 12 gallons in the saddle tanks. Then when it does start, it runs great. Last time it started, about two weeks ago, I mowed a quarter acre with it before I put it way.
 
#5 ·
Indiana_Tom said:
Thanks for the replies. And for the service manual. I went out and checked the spark and it looks good. Then I put the plugs back in and cranked for about 30 seconds. Man when it backfires in my tin barn, it will jar your teeth. :) Then, I pulled one of the plugs and it seemed dry. Maybe it is not getting fuel thru the carb?????? But when it finally starts, it purrs like a kitten. The gas in it was from last fall, late in the year but I have never had it go bad. It is either 10 or 12 gallons in the saddle tanks. Then when it does start, it runs great. Last time it started, about two weeks ago, I mowed a quarter acre with it before I put it way.
Click to expand...
With the choke on for that long, the plugs should have been wet. Try putting a little fresh gas directly in the carb. Try starting it.
The gas today is garbage, especially with ethanol. I bet your carb could use a good cleaning as well.
 
Discussion starter · #6 ·
I figure they should have bee wet when I pulled them. I will try removing the hose on the carb coming from the air cleaner and then giving it a drink of gas. That will have to be in the morning. The carb appears easy to take off but I am not sure what to do to clean one other than spraying it good with cleaner. I had wondered about the solenoid but it takes a very skinny wrench to take it off. I hope it is not bad because they are so expensive. And I am not sure if it could cause this problem or not.
 
#7 ·
If the solenoid was bad, it would not run at all. Take off the air cleaner and pour a little gas down the throat of the carb. Dont pour too much or you will flood the engine. Try and start the engine and post your results.
 
#8 ·
Sometimes the solenoid clicks but it doesn't actually pull the plunger back to open the gas port into the carb. Mine had a gunk build up around it and would hang up every once in a while. Pulled the solenoid off and cleaned the gunk and and fires up like it should. You will need a thin 1/2" wrench if I remember correctly to remove the solenoid.
 
Discussion starter · #9 ·
Ok, went back out to try the gas down the throat. I may have over done the gas. I am not sure. Not even a sputter. I could have flooded it but after working all day I will have to wait till tomorrow now. I plan to make one more trip out to put the float charger on it for the night.

I had tried to take the solenoid and check it but I will have to find a wrench that is thin enough to fit in the skinny access area.

Thanks for all the suggestions guys.
 
#10 ·
I dont believe it is your solenoid. Gas down the throat goes right to the cylinder and should light off if you have spark and compression. I would check the plugs to see if they are wet. You may have put too much gas in. That is why I said, a "little." If the plugs are wet, let them air dry and try again tomorrow.
 
#13 ·
Condensation forms in the air space of partially filled tanks and will collect at the bottom where the pickups are. It's highly doubtful that just sitting for a couple months caused any mechanical ailments. Plugs look fine outside an engine but under the pressure of compression they can snuff out. I would replace them. If you don't want to drain the tanks run some Seafoam through it for 15 minutes WOT. Top off tanks with ethanol free fuel.
 
Discussion starter · #14 ·
I do need to get new plugs so that will be on the list the next time I get to town. I know about the condensation and so when I know it will set like over winter, I fill the tanks to prevent the condensation. I have an idea that it has to be something in the carb since it was running so nicely when I put it in the barn for the winter. I started it once or twice during the winter but then around early Feb when I tried to start it it would not start. I do the same thing with my Harley. Starting it every thirty days keeps the fuel system from getting gummed up.
 
Discussion starter · #18 ·
Well, I did not get many things checked out on the zero turn today but I will tell you what I did. I poured a very small amount of gas right into the carb first thing and tried to start it. It didn't even sputter. Now it could be that I did not put enough in. Anyway, I started cranking it and choking it of and on. After choking for a while 15 to 20 seconds I pushed the choke in and continued to crank. Finally I got a sputter. Then I choked it again for a several seconds then pushed the choke in and got another sputter after a few cranks. The motor has always been a little cold blooded and it is a little hard to work the choke and keep it running when it first starts. After a few seconds it was purring like a kitten again. Now, I really need to get this starting problem fixed but I also really really needed to get some mowing done. So I mowed 4 acres before it got too long to cut. After that I parked it just outside the garage. Two hours later, I started it but it took several cranks again. After having to pick up 2000 downed limbs, I was too worn out to think about motor problems. I am not so sure the problem isn't the fuel pump after all. Since it is only about $23 I think, I will just replace it. I did do a test by replacing the line that left the fuel pump and went to the carb and ran it into a jar. It looked like it was pumping but now I am not sure if it was not just a gravity flow.

Ok, that was todays progress.
 
Discussion starter · #20 ·
Ok, finely back to the zero turn. Getting a new steel garage roof put on and got sidetracked.

I stopped at the small engine shop yesterday and got the new plugs and a new fuel filter. I had called and talked to the attendant the day before and he said he had the fuel pump for it in stock. The price was $29 so I figured I would just get it but wanted to check the fuel filter again before I opened the package on the new one. But, when I got there the man I talked to was off work that day and a young gal that is fairly new at the shop was the only one there. She said if she had been there for 20 years like the man had she would know which one it was too but since she was new, She was a little lost. Of course, it was my fault because I could only remember the FH721V and not the other numbers she needed to look it up. So that is a long story about why I did not get the pump.

Got the new plugs gapped and in and the fuel filter on.

Now when I checked the fuel pump the first time several days ago, I pulled the hose that went to the carburetor, off the pump. Then I used a 5 ft length of clear hose I had and pushed it on the open outlet on the pump. Put the other end in a glass gar and cranked the engine. Appeared to have a good flow of gas. Now today, after using my head a little I decided I had a good chance of just seeing a gravity feed of gas. So I did the same thing but held the hose up to eye level which is 2 feet above the saddle tanks and cranked the engine. The gas would bob up and down but would not go any higher in the hose. So I am sure the problem is that I need a new fuel pump. I hate it when I make a silly mistake when checking something. But I want to thank everyone for their help in tracking down this problem.
 
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