F911 Kawasaki FD620D engine weak

[Bogart]

It will not reach max rpm or maintain rpm or power going up a slight incline with blades engaged. If I turn the blades off it will pick its speed back up but not where it should be. No load WOT should be 3800 rpm. Started at 3200, I have it up to 3500. I can push the throttle linkage at the carburetor by hand and get higher rpm easy.
I have:
Dismantled and cleaned the carb
Tested the fuel shut off solenoid
Cleaned fuel tank, fresh gas
Air filter is clean and no difference with filter removed
New fuel pump and filter
Adjusted the WOT per factory manual
Adjusted throttle mounting plate per fm
Adjusted the governor per fm

The only thing I can think of I haven't done is adjust the valves. Could that be it?

TIA

 

[zzvyb6]

Consider new spark plugs, especially if you've been using gas with ethanol in it. My F525 Kawasaki does the same thing. I was using the 15% ethanol gas in my truck (designed for it) and my gas mower (not designed for it). Truck is OK. Mowers and small motors are not. My Yamaha 4 wheeler (single cylinder) is also prone to the ethanol plug 'poisoning' for the want of a better word. A higher heat range is not necessary. Just a new uncontaminated set of plugs.


There is another thread on this forum concerned with the ethanol issue. Just about every station around here is up to 15%

 

[Bogart]

I'm glad I don't have any hair to pull out.

BOTH intake rockers were off their pushrods. How was this thing even running? Put them back, adjusted, turned the engine over by hand to make sure all valves were operating correctly. With much anticipation went for a test run. SAME THING!! Still losing power under the slightest incline. I am at my wits end...

Edit; Compression test 250 on one side, 30 on the side with the valve cover still on. Pull cover, rocker is off pushrod. Valve wants to stick in guide. Put rocker back on, compression 235. Gonna change oil with Royal Purple 10w-30 and let it idle for an hour, maybe it will loosen the valve in it's guide.

Thanks zzvyb6, no ethanol here.

 

[Spudland_Dave]

Edit; Compression test 250 on one side, 30 on the side with the valve cover still on. Pull cover, rocker is off pushrod. Valve wants to stick in guide. Put rocker back on, compression 235. Gonna change oil with Royal Purple 10w-30 and let it idle for an hour, maybe it will loosen the valve in it's guide.

Thanks zzvyb6, no ethanol here.

I was gonna post last night but didnt get around to it....My FIL had a similar issue....ended up being a bunch of bent push rods. He only found out when the original timing gear (plastic) went south...after replacing all the pushrods, new timing gear, and doing a valve job, she now runs like it should. From what I gather, its a pretty common issue on a certian range of the Kawaski's.

 

[Bogart]

I was gonna post last night but didnt get around to it....My FIL had a similar issue....ended up being a bunch of bent push rods. He only found out when the original timing gear (plastic) went south...after replacing all the pushrods, new timing gear, and doing a valve job, she now runs like it should. From what I gather, its a pretty common issue on a certian range of the Kawaski's.

Thanks Dave.