View Full Version : 21hp Kawasaki Zturn runs for 1 hr then looses power

06-03-2007, 12:17 PM
I've got a 3 year old Ferris with a 21 Kawasaki and about 700 hours. For the past several months I've been chasing problems keeping it running.

As of today, I can't run the PTO on the right tank, but I can run the engine on the right tank.

I can mow on the left tank (full , 1/2 full , nearly empty...doesn't matter) for about 1 hour to 1 1/4 hours (outside temperature doesn't make any difference ...same results). After this time it begins to die, like it's loaded down, ease off on handles and you can nurse it for about another 15 minutes or so.

Checked the clutch gap. OK
Drained fuel from carb petcock when it acts up. No difference noted.
Cleaned the carburetor.
Plugs were changed in Fall 06.
Mows great (for an hour) in nearly any conditions.

My dealer has been useless in solving this...any suggestions?


06-03-2007, 12:56 PM
Does the engine shut down completely ? If so does it start right back up ?

06-03-2007, 01:00 PM
The only thing I can think of is replacing first the inline fuel filters, but also the in-tank ones.
Beyond that, I guess you have to know if all the maintenance is up to date, you might try switching to premium fuel for a gas tank full, also I would be for pulling the carburetor bowl and cleaning all the float mechanism and inside the bowl out real good.

Eric D
06-03-2007, 01:01 PM
It sounds like an over heating issue to me if you can keep it going by “ease of on handles”. Check to make sure that cooling fins are clear. Had a unit brought in that a mouse built a nest right on top of the cylinder under that baffling where you couldn’t see it. The mower would work fine for a while until the temp got up high enough to start seizing the piston in the bore. Not to mention the chewed-up wires!

Ignitions coils can start to flake-out with heat as well.

Eric D

06-03-2007, 01:06 PM

I was thinking possibly a restriction in the tank valve (trash) not letting enough fuel flow to run under load but just enough to run. Possibly the vent in the gas cap but most show up before a hour but could still be possible.

Or could even be a coil heating up and dropping one cylinder, It can be difficult to denote on some twins if running on both cylinders without a spark test.

06-04-2007, 08:26 AM
I have a 25 hp. Ferris on 1500 and had a problem with it sucking air at the barbed fitting at the top of the tank. My dealer gave me a new pick up line and so far so good.

Eric D
06-04-2007, 09:35 AM

Any news on the engine issue?

Eric D

06-12-2007, 08:50 AM
OK, feel kind of stupid, but since my dealer had same problem locating problem I don't feel too bad.

Problem was a partially clogged inline fue filter.

Because the left tank fuel line is about 9" long but the right side is 2 ' plus, the right side line was not able to pull fuel through with the PTO on but the left side could pull fuel until the line got warm enough to start collapsing rather than pull fuel through a partly clogged fuel filter.

Lesson learned: Just change out all the inlline fuel filters each year as part of end-of-season maintenance.

Thanks guys.


Eric D
06-12-2007, 10:25 AM
Lesson learned: Just change out all the inlline fuel filters each year as part of end-of-season maintenance.

It is the little stuff that always seems to bite, changing out the filters is good advice.

Thanks for sharing!

Eric D