I have a Scag Freedom Z with a Kawasaki FH580V-AW00 that is 14 years old with less than 700 hours. I've changed the oil and filter regularly and run only non-ethanol 87 octane. Never had any problems until now. Recently it wouldn't start and seemed the cranking speed was slower than in the past. I never really paid much attention to the cranking speed because it always started quickly. Because the battery was old, I went ahead and replaced it. Same problem. On one attempt it did start with the use of some starting fluid. Experienced a couple of backfires in the process. I shut it down after a few minutes and it restarted fine. After returning from a trip and no activity with the mower for a couple of weeks, again it won't start. Slow turn over.
I removed both plugs to see if there would be any change with no compression. Still slow. I had replaced the plugs 5 months ago. I can see some spark with the plugs in place and the plug wire held near the plug terminal. I know an ignition coil can be "bad" and still produce a spark, albeit inadequate, but it doesn't seem like both coils would fail at the same time. And of course defective coils wouldn't cause a sluggish crank. I've wondered if a hotter spark would result in a good start up at what I think is a sluggish crank.
Is it safe to assume that there is no issue with the starter because it does engage and turn the engine?
Prime suspect is bad power cables
Run boosters from the battery directly to a good ground on the engine and directly to the + on the starter
If it cranks faster then one ( or both ) of the battery cables need attention.
Prime suspect is bad power cables
Run boosters from the battery directly to a good ground on the engine and directly to the + on the starter
If it cranks faster then one ( or both ) of the battery cables need attention.
I tried the suggestions above without any change. I've removed the starter and connected directly to a good auto battery using heavy jumper cables. The starter seems to run fine with no load. Using a strobe app I downloaded to my iPhone it appears that the starter is spinning at around 1200 rpm. (I don't have a lot of confidence in the accuracy of this app.) Spins ccw looking at the gear end. No unusual sounds. The gear does initially run out to around 3/8", then returns to about 1/4". Returns to 0" when powered off.
Does anyone know what the unloaded rpm should be? Is there any way to simulate a load?
I can turn the flywheel with little difficulty. I have not idea how much force it should take. Don't laugh, but when i put a torque wrench on the flywheel nut it appears to take about 10 ft lb to turn it through a compression stroke.
Is the starter growly when you try to start it? Those old starters on the FH engines were notorious for the top bushing to get dry and drag and sound growly. Try lubricating the top bushing. Don't get any lube on the drive between the driver and the gear or it will just spin when it engages the flywheel.
As stated above, I attached cables directly from good battery to starter. The starter barely turns the engine.
#8
Scrubcadet10
If the starter still is not able to spin the engine with the plugs out, and hooked directly to the battery (with jumpers), and the battery is good, to me that points to a bad starter.
Then either the engine is bad or the starter is bad
Try it with one plug removed
The other plug must be grounded or you can damage the magneto
If the engine starts thn the starter is bad
If the engine does not fire then the engine is bad .
I had a local repair shop pick up the mower. They said it's not uncommon for a start to appear to operate OK when on the bench, but "bog down" under load (as I suspected). They replaced the starter, and adjusted the valves while they had it. Now it starts faster than ever and runs great.
