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View Full Version : Kawasaki FH680 Hard Starting when Hot


D C
04-17-2009, 07:30 PM
I have a new-to-me Cub Cadet with the 23hp Kawi FH680 with about 280 hours.

When cold, it fires right up.
When hot, it doesn't. Coughs, spits, backfires through the carb & exhaust & even has had flames coming from the exhaust (which was admittedly kinda cool, even though my wife was :eek: ) Doesn't help mugh if the choke is on or off. I've found that if I play with the choke a bit I can get it to start with continued cranking, but certainly not very easy.

Plugs: Gapped fine & they look great
Compression: Good in both cylinders
Stator/Coil Gaps: Reset those today
Carb: Everything looks good, took it off, cleaned it, checked the float, etc... (I was surprised to see that this thing doesn't have any mixture screws, or hardly any adjustments for that matter)

When it's running with the mower engaged, I notice some bogging & exhaust popping when going up hills. Trying to just even the tips of the grass off and not really cutting to speak of, and the slopes aren't very steep at all.

I did have the flywheel off today to repair the stator wires. One of them had rubbed through, and I suspected that it grounding out was maybe causing part of the problem. Fixed that and after cleaning the carb & everything, it's only slightly easier to start when hot.

Could I be having a coil issue, or a stator issue from that wire being grounded out (if it was)?

Anywhere else to look?
I know it's coming up on the 300 hour maintenance and I'm planning on at least checking the valve lash in the near future.

Thanks!
Dave

Restrorob
04-17-2009, 08:05 PM
Dave,

You need to go ahead and check the valves, In most cases backfiring and fuel spit-back is a sign the valves are out of adjustment.

ABeautifulCutAboveInc.
04-18-2009, 08:25 AM
I have the same problem. I have the 23hp Kawi, FH680V on my Hustler. The motor has been well maintained and just passed 800 hours. New plug, fuel filter, coil and plug wire. Restrorob, I'm fairly mechanicaly enclined, what's the procedure to check the valves?

D C
04-18-2009, 09:16 AM
I found the engine service manual online. It has the procedure (as well as everything else) http://www.lapab.com/Engine%20FH451V-FH721V.pdf

Herbert02
01-31-2011, 01:17 PM
Hey DC! What was wrong with it? Was is the valves?