Any luck? Is the valve bent or some other problem?
It finally died JD F510
- Thread starter SHOZ
- Start date
I wonder if it dropped a valve seat, not super common on Kawasakis, but it can happen especially if there was a mouse nest or something and it overheated.
Be careful mowing with your new ZTrak. The engine will be fine, and the hydros are decent for homeowner grade, but I've literally had 3 of them in the last 2 months with bent decks.
Be careful mowing with your new ZTrak. The engine will be fine, and the hydros are decent for homeowner grade, but I've literally had 3 of them in the last 2 months with bent decks.
I was reading they beefed up the decks on the 2023 models. One of my concerns vs the older F510 is the sheet metal framing and low towing ability. They also brag about how well it mows in tall grass. That will be getting the extreme test.
That's good the deck is stronger, it definitely seems to be the weak point on the older models, or at least the mounting/lifting points. I can't comment on the high grass, since with all the test mowing I do in different sections of my yard the grass never really gets too high.
I would definitely fix the F510 if you can, even if you have to buy a new/used cylinder head. They are great mowers with a unique shared oil pan/hydro drive system. It was made back when even the homeowner grade John Deeres had a build quality above everyone else.
When I got it they had come out with the home owner line LX I think. The F510 was what I wanted but the local Deere dealer didn't want to even order it. Some BS about trade in value and what he could sell it for used. That was 23 years ago!
Anyway I went to another dealer over in Indiana and they were quite happy to sell at a discount and got one direct from the factory in Moline IL in a week. They were not so accommodating this time though.
But last year I towed around a semi load of shredded wood mulch and about 60 tons of cement and gravel rip rap. I think that is what overheated it as most of the time the engine was at low speed. No way can the new one do that though as far as towing.
Mobil 1 0w40 for most of it's life. And a oil cooler that was a bypass style ATF cooler. This caused problems below 30F last early spring. Never really used it in the cold previously. But without the cooler the oil in the sump with 5w30 would go over 300F after a 2 hr mow on a +90F day. Put the cooler on many years ago. Temp was usually under 210F-230F after that.
Overheating the engine will cause the push rods to come loose as you've found out.
Blowing air into the plug port didn't do anything. The valve moves in smoothly when I pry it and returns sharply but only about half way.
I bet the springs and weights on the cam for the compression release fell apart and is holding the exhaust valve open.
I bet the springs and weights on the cam for the compression release fell apart and is holding the exhaust valve open.
I don't think that's possible. The action of the compression release works through the pushrod. If I'm looking at your picture correctly, the exhaust valve's pushrod is not in place. The valve should be fully closed.
As suggested above, the valve seat may have fallen out, or the valve could be damaged. Possibly even some debris holding it open.
A strange one is when a muffler's internals come apart (typically a catalytic muffler) and bits of the honeycomb make it backwards into the cylinder. It is possible this type of debris is at fault. But I'm guessing it is a valve seat.
You're both not Wrong. The flat tappet valve rides on the camshaft lobe & the Decompression sprung arm comes up next to that lobe to bump the exhaust valve open slightly. The OP may be correct in that it fell apart but what I would do is follow this advice to put the pushrod back together & rotate the crank & watch for this minor "Bump" from the valve cover access. That might tell you if the decompression system is busted. Make sure to adjust the valve springs first to spec.I don't think that's possible. The action of the compression release works through the pushrod. If I'm looking at your picture correctly, the exhaust valve's pushrod is not in place. The valve should be fully closed.
As suggested above, the valve seat may have fallen out, or the valve could be damaged. Possibly even some debris holding it open.
A strange one is when a muffler's internals come apart (typically a catalytic muffler) and bits of the honeycomb make it backwards into the cylinder. It is possible this type of debris is at fault. But I'm guessing it is a valve seat.
Last edited:
Yes looking at the diagrams the cam and decompression mechanism is way down by the crank. It says it should open the exhaust valve just slightly after the intake valve opens below 600 rpm or so.
No way to tell by rotating as it is already held open much more that the slight lift it says. .25mm or so.
No way to tell by rotating as it is already held open much more that the slight lift it says. .25mm or so.
If it won't close all the way, my bet is on the valve seat being the problem.
I will when I have time. Looking at the exhaust bolts, it won't be fun.
You can do it
Kawasaki put a lot of metal covers, over the engine, on these & I had to remove a lot of them to get in there though.
Well I need to get it out of the shed for the new one. So I'll make some room out on the driveway pad and start taking things off. The fender and that cross brace need to come off and the shroud. Then I can start making offers to the exhaust bolt gods with some soaker stuff.