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Engine won't start when hot. Kawasaki FH721V-AS32 Looking for any ideas on where to go, compression is 150.

flporter said:

Engine won't start when hot. Kawasaki FH721V-AS32 Looking for any ideas on where to go, compression is 150.

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One possibility is the coils. Do you have spark?

sjessen said:

One possibility is the coils. Do you have spark?

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yes, and have put new coils on it.

Is the engine getting hot? Does it just quit or act like it is running out of gas? If the latter, sometimes the problem is with the gas cap.

It starts fine the first time when cold. But if it is turned off, it just won't start when it is hot and has been running. When it cools off, it starts fine.

Hopefully, someone will post who has actual experience with this engine and/or mechanical ability.

Suppose in the short run you could leave it running as you go from lawn to lawn.

beginning to sound right!

Can you hear the fuel solenoid click when you turn the key to ignition only? (not to start) After you run it, the little solenoid coil may be failing enough to not open the fuel shutoff. gregjo1948

gregjo1948 said:

Can you hear the fuel solenoid click when you turn the key to ignition only? (not to start) After you run it, the little solenoid coil may be failing enough to not open the fuel shutoff. gregjo1948

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I am having the same exact problem. Was told its the carburetor. Lot of money to be guessing? Any for sures out there. Once it's running it sound great . Throttle it up quick and it back fires big. Greg

Greg1Warden said:

I am having the same exact problem. Was told its the carburetor. Lot of money to be guessing? Any for sures out there. Once it's running it sound great . Throttle it up quick and it back fires big. Greg

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I also hear the solenoid click each time i turn to on position. I take the air cleaner hose off the carb and fuel is in the outside of the carb , heavy. Eventually starts after hose is off, but wearing down battery. Greg

Service manual
http://www.parish-supply.com/pdf/kawasaki-fh541v-service-manual.pdf

Greg,

Did you find out what was wrong? I have one doing the same thing

"K&T Parts House Lawn Mower Parts and Chain Saw & Trimmer Parts" your manual is 12 down from top. See troubleshooting section 10.3.

I have been told by mechanics at Bramble Mower (Great Guys) it is the carburetor. I am having it rebuilt, Not buying a new one. YET (350.00). Everything else looks fine. My hands can't do those little parts. Greg

Yeah i broke down and am having carb rebuilt too..gotta quit thinking I can fix everything myself..How much is this aggravation costing me?

It could possibly be your ignition module too. My fc420v did the same thing until i replaced the module.

Remove blower housing top of engine and remove all dirt & debris, take your time doing this procedure getting everything removed from vanes on heads, flywheel, etc. with shop vac or by hand, you will be surprised at the amount of crud buildup.

flporter said:

Engine won't start when hot. Kawasaki FH721V-AS32 Looking for any ideas on where to go, compression is 150.

Click to expand...

Notice this is an old post, but I'm having the same problem. Was there ever a definite resolution? I'm pretty handy, but not wanting to tackle any big repairs myself and certainly don't want to be guessing.
Thanks, Don

:welcome:
Don,
You would not walk into the doctors and say "I feel the same as the other guy" and to some extent mowers are the same

So exactly what do see see, hear , smell & feel when you turn the key ?
How old is the engine ?
What is it on?
Does the engine crank & not star ?
Does it fire a couple of times but not carry on"
Dose it turn over ?

Silly little things happen like not having enough oil so once the engine has been running for a while and oil is splashed all over the engine the oil level in the sump drops just far enough for a slightly out of calibration oil switch to trip & kill the spark, particualry if the mower was parked slightly up hill. ( A real life call out cost the customer $ 60 to be told to add 4 oz of oil )

bertsmobile1,
Thanks for your response. Here's some more detail:
Only fails to crank when hot. Turns over strong (new battery, new plugs). A wait of 5 to 10 minutes cooling usually is enough to start. I drive about 300 yards to gas station and have to turn off engine to refill so this is frustrating when I have to sit a the pump for 10 minutes. Once I start cutting, I don't stop for about 3 hours or leave engine running on short breaks.
No particular smell unless engine gets flooded. Tried with choke on/off, starter engaged for short/longer periods.
Loud sound from flywheel or starter (I think). Almost sounds like metal scraping and seems to "grind" to a stop when ignition is turned off (after attempt to start). This occurs even on a cold start but once it starts (quickly), it runs smooth and at "full" RPM.
I checked the oil level and it was fine. I read that I should clean out the air cooling fan and blades. That makes some since considering the noise per above. Also read something about the pressure in the tank building up greater than the engine pressure if the gas cap air intake is blocked. I'll try removing the caps (2) next time this happens.
I've checked the air filter and cleaned it (have ordered a new one, just in case). The mower/engine is 13-14 years old (bought new in 2004) and has been awesome. The mower is a Cub Cadet KW60 (Tank). Residential use only, but I'm on 5 acres with about 4 acres of grass that I cut weekly in summer and mulch leaves several times in fall/winter.
Hope this helps and thanks again for any suggestions.
Don

Crank = turn
SO are you saying it rotates ( cranks ) but does not fire, just spins & does nothing. ?

Correct. It rotates but does not start. I guess I used "crank" incorrectly as in " crank it up". Lawn Mower mechanic I spoke to yesterday says could be the starter or valves need to be adjusted (never been done). Probably gonna take it to him this week.

PapaDonLogan said:

Correct. It rotates but does not start. I guess I used "crank" incorrectly as in " crank it up". Lawn Mower mechanic I spoke to yesterday says could be the starter or valves need to be adjusted (never been done). Probably gonna take it to him this week.

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It sounds like your Lawn Mower mechanic misunderstood your problem. He gave you possible problems which may cause an engine NOT to crank.

A lot of confusion on here comes from words meaning different things to people. Maybe some kind of sticky post saying "Use these definitions when asking a question" with the definitions of words to be used to describe their problem would help, such as:

Crank = Starter spins the engine, but does not fire.

Turns over = Same definition as crank.

Fires = Starter spins the engine, and the firing sounds and possibly smoke comes from the exhaust, but the engine does not begin running on its own.

And so on.

I'm not criticizing, just suggesting.

Not starting hot is a funny thing to diagnose.
Usually it is a mal adjusted carb or a sticky valve.
After that you have a magneto coil on it's way out but I would expect it suddenly stop during mowing, or at least miss when hot.
Valve adjustment is an easy job you can do at home and takes about 1/2 hour or so depending upon how much cleaning has to be done.
The valve lash should be checked every 200 hours or so which would be every 2nd or 3rd season and go hand in hand with pulling the blower housing & cleaning the fins.

Unless the engine was turning over slowly it is not likely to be the starter, starters rarely give any problems till the drive gear has worn thin.
I have replaced 1 starter in 700 services and 2 sets of brushes and all of these were on mowers that were left in the weather.

If you want to have a go yourself then live with it for now and and pull it down at the end of the season.
Kawasaki manuals are all here http://www.mymowerparts.com/about_us.php and the only part you will need to but is a pair of rocker cover gaskets .
BEst done before you change the oil as the gaskets are generally stuck fast and bits of gasket always end up in the engine.

Re: kawasaki engine starter does not hit flywheel

I took the starter off checked put new solenoid work fine put I back on still does not flywheel?

PapaDonLogan said:

Notice this is an old post, but I'm having the same problem. Was there ever a definite resolution? I'm pretty handy, but not wanting to tackle any big repairs myself and certainly don't want to be guessing.
Thanks, Don

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Don't know if you found your problem, but had the same thing on my Hustler Z with FH 721V, adjusted the valves, took care of the problem.

I have a 2006 Ferris with FH721V - same problem over last two years. I adjusted valves, they were .011, so put them to .004. Seemed to help some, but not completely. Was able to start it hot twice, but not consistent. Compression shows 79 psi but spark plugs are black (new plugs 2 years ago) Mower has new OEM carb (thought that was issue). Still seems to be flooding when trying to start hot. I have ordered new ignition coils - just throwing things at it now, tired of misdiagnosing. (way cheaper than new mower) I will keep at it until I get the problem fixed. Hope to report back soon with good news.

1.Ignition control unit
2.Lower the float level inside the carb to slightly lean it out.
3.Adjust pilot screw.
4.Use real gas and stabilizer year round.
5.Use a fuel shutoff valve and a good paper fuel filter every time you mow.
6.Keep oil level at the FULL mark on a flat surface. Not in the back of a trailer parked uphill.
7.Remove blower/starter cover and clean out all the dirt, oil, grass and bugs from the engine block cooling fins.
8.Valve clearance in proper spec?
9.Good supply of cold beers?

slomo

JD is best said:

It could possibly be your ignition module too. My fc420v did the same thing until i replaced the module.

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I have replaced ignition modules with the same type of issues on cars and pick ups.

slomo said:

1.Ignition control unit
2.Lower the float level inside the carb to slightly lean it out.
3.Adjust pilot screw.
4.Use real gas and stabilizer year round.
5.Use a fuel shutoff valve and a good paper fuel filter every time you mow.
6.Keep oil level at the FULL mark on a flat surface. Not in the back of a trailer parked uphill.
7.Remove blower/starter cover and clean out all the dirt, oil, grass and bugs from the engine block cooling fins.
8.Valve clearance in proper spec?
9.Good supply of cold beers?

slomo

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On some carburetor you can't adjust float level.

Tinker Withit said:

I have a 2006 Ferris with FH721V - same problem over last two years. I adjusted valves, they were .011, so put them to .004. Seemed to help some, but not completely. Was able to start it hot twice, but not consistent. Compression shows 79 psi but spark plugs are black (new plugs 2 years ago) Mower has new OEM carb (thought that was issue). Still seems to be flooding when trying to start hot. I have ordered new ignition coils - just throwing things at it now, tired of misdiagnosing. (way cheaper than new mower) I will keep at it until I get the problem fixed. Hope to report back soon with good news.
[/QUO

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If it has an ignition module it would cause a no spark when hot,Check for spark when hot after engine dies. Bad coils could would do that.