KAW FH500V-BS11 loses power after 15 minutes

[BBQGuy]

KAW FH500V-BS11 (17HP) on a JD LT277AWS purchased new 1999.
After about an hour of cutting grass, stopped mower for about 15 minutes.
When restarting, motor sluggishly accelerated. When engaging the blade, the motor starts losing power, laboring but did not die, disengaged the blades and returned to the shop.
Returning the next day. motor stated as normal. After cutting grass for about 15 minutes, the motor started loosing power again.
Thinking of a fuel issue, emptied the carburetor bowl, it was clean. Fuel solenoid tested fine. Cleaned air filter/ no oil in the filter.
Replaced the fuel filter, it needed it. Plugs look ok, they are 1 year old, have not replaced.
A cold motor starts and seems to run normal, but after about 15 minutes it looses power.

Suggestions of where to go from here.

 

[mechanic mark]

Engine cold,remove blower housing, cover over engine, & clean engine completely, I prefer using a Shop Vac & cleaning engine by hand using small dental like instruments, no water is used. You may choose to use air hose gun, wear Safety Glasses. Clean out all of the crud between engine fins, etc. Let us know how it goes, thanks, Mark

 

[randyjoe]

KAW FH500V-BS11 (17HP) on a JD LT277AWS purchased new 1999.
After about an hour of cutting grass, stopped mower for about 15 minutes.
When restarting, motor sluggishly accelerated. When engaging the blade, the motor starts losing power, laboring but did not die, disengaged the blades and returned to the shop.
Returning the next day. motor stated as normal. After cutting grass for about 15 minutes, the motor started loosing power again.
Thinking of a fuel issue, emptied the carburetor bowl, it was clean. Fuel solenoid tested fine. Cleaned air filter/ no oil in the filter.
Replaced the fuel filter, it needed it. Plugs look ok, they are 1 year old, have not replaced.
A cold motor starts and seems to run normal, but after about 15 minutes it looses power.

Suggestions of where to go from here.

Check your valves for clearance, when metal heats up it expands, may be throwing your valves settings off .003 intake .005 exhaust when cold. I hope this helps out

 

[bertsmobile1]

Looses power ?
Misses, backfires , surges , sound fine but just no balls ?

 

[slomo]

Engine cold,remove blower housing, cover over engine, & clean engine completely, I prefer using a Shop Vac & cleaning engine by hand using small dental like instruments, no water is used. You may choose to use air hose gun, wear Safety Glasses. Clean out all of the crud between engine fins, etc. Let us know how it goes, thanks, Mark

Say it again MM.

Soap, water and a scrub brush, carb covered with a plastic bag. How ever you want to clean the fins. This is a yearly maintenance deal in ALL engine manuals.

slomo

 

[slomo]

Back to regular programming, since you found a filthy fuel filter, I would drain and flush the tank. Run new fuel line, paper filter and new shutoff valve. Verify good fuel flow AT carb fuel inlet.

Valve adjustment wouldn't hurt the ol' girl either. Do this yearly as well to keep her starting easily.

Then if it still flakes out, get a simple inline spark tester. Is the sparky blue or orange. Test in low light or dark conditions.

When checking the oil level, DO NOT SCREW THE DIPSTICK ALL THE WAY IN to verify level. Most Kawi's, you park the stick on TOP of the threads, remove and check level. It's even printed on the stick in English. If you knew this, disregard.

slomo

 

[BBQGuy]

Thank you for the replies.
Will give they a go.

 

[BBQGuy]

After a few weeks of vacation had some time to work on the engine.
Drained the fuel and add new. Replaced the fuel filter again.
Changed the oil, new filter, plugs, air filter, so a basic tune-up.
Adjusted the valves. Only 2 of the 4 valves (lower on on each side) were outside of clearance spec's.
Cranked up, cut some grass for about 10 minutes and the engine started losing power again.
Came back the nest day, engine starts, runs well, after 10 minutes it again starts losing power.
Any assistance is appreciated.

 

[slomo]

After a few weeks of vacation had some time to work on the engine.
Drained the fuel and add new. Replaced the fuel filter again.
Changed the oil, new filter, plugs, air filter, so a basic tune-up.
Adjusted the valves. Only 2 of the 4 valves (lower on on each side) were outside of clearance spec's.
Cranked up, cut some grass for about 10 minutes and the engine started losing power again.
Came back the nest day, engine starts, runs well, after 10 minutes it again starts losing power.
Any assistance is appreciated.

Did you clean the cylinder cooling fins? Wondering if the little guy is over heating? Should remove the shroud yearly and clean the fins. Maybe more if you store in a barn or have mice around.

Might want to flush the fuel tank out with gas.

Ignition coil might be weak. Take an old spark plug. Gap it to 6mm or 0.25". Crank the engine over and watch for spark. Should be a nice blue to purplish color. This will load test the coil. Simple 0.030" out of the engine is not much of a load.

slomo

 

[bertsmobile1]

Try mowing with the fuel cap loose.
Check the valve lash again, it it is out again you could have a loose guide.
I assume you have pulled the carb off & cleaned it out properly ? although I did not see you mention this .
Crud builds up in carb solenoids preventing them fully retracting and partially clogs jets