I recently acquired a cub cadet zero turn with a Kawasaki fr691v. It has lived its whole life outside. It’s a 2012 model. It had been sitting for three years because it stopped moving according to the previous owner. Turns out the transmission belt was bad. After replacing the belt i drove it around and heard a metallic rattling noise. It turns out one cylinder had one bent pushrod and both pushrods had come off of the rockers. This cylinder had a large lump of grass packed into it. The cylinder definitely overheated and caused an issue. Anyway i got a used cylinder head and cleaned everything up and replaced it. I actually ended up cleaning both cylinder heads and lapped the valves. I ran a compression test on the cylinders and both are right under 100psi which is good according to the manual. I adjusted the valves and the engine fires right up but at full throttle it smoke’s horribly. It has 3 year old gas in it but i mixed in some fresh. I did not touch the carburetor. It seems to run really well. The previous owner did not mention any engine issues. I don’t think he realized there was an issue as it ran pretty decently on one cylinder. The engine has a little under 350 hours on it. I am not sure what to try next. My fear is the one cylinder hasn’t been working for a long time and has been washed with fuel and now the piston rings and bore are shot but I don’t want to jump to any conclusions yet as the cylinder looked visually pretty good to me. Also on the bad cylinder the intake valve where it seats was eaten away terrible say .005-.010. Also noticed when i took the valve cover off that it was milky inside. The other valve cover had normal black engine oil.
Kawasaki fr691v smokes badly
- Thread starter joegreen
- Start date
Propflux01
$100 Site Donor 2025
Check those coils to see if both are working. That grass might have overheated and warped that cylinder. My question is, how did the rods get bent when I see no evidence of any kind of valve contact?
This may not be your only problem but if you can check the rocker mount nut that comes loose (not talking about adjustment of the valve lash).
100 PSI is still good. I'd possibly try a new carb to see if that may be causing the issue of smoke. How long have you run it after head replacement?
100 PSI is still good. I'd possibly try a new carb to see if that may be causing the issue of smoke. How long have you run it after head replacement?
actually you just reminded me. I forgot when i removed the valve cover the exhaust rocker mount bolt was loose so i think that is why the pushrod fell off but was not bent. The intake pushrod im not sure how it came off but i was able to remove both valves although the intake valve was worn horribly. I have run it probably a total of 20 minutes.
Propflux01
$100 Site Donor 2025
Maybe coil misfiring?
Possibly the overheated head warped enough to allow oil into the combustion chamber through the slight gap in the head gasket area. If the exhaust smoke smells like burnt oil and it smokes heavier when the engine is under an extra heavy load, warped head.
The old overheated head is trash. I have a new head that i cleaned up and checked for flatness on a surface plate. I ran it again today and it smoked pretty bad. I definitely think it’s going to need a teardown. Choke is fully opened. Ill try a basic leakdown test next.
With the amount of debris blocking the cooling fins, i think the rings along with the head are shot from overheating.
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Hand you tried putting a timing light or a spark tester on the questionable cylinder?
What color is the smoke?
What color is the smoke?
No I have not changed the oil yet. I didn’t want to waste new oil. I did have to add about 1/2 quart though. No idea on the maintenance history although the cylinder heads were very clean under the valve covers with no varnish.
Yes that is the dead cylinder side
No i have not tried a timing light or spark tester. It starts very easily and runs good so i assume both plugs are firing properly. I don’t think there is any way to change the timing. The smoke is whitish blue.
Blue smoke is oil burning, so my money is on piston/cylinder/rings being the issue.
Maybe not since the cylinder was cooked due to the cooling fins being blocked.Sounds like a job for VRP
