Conquest specific engine problems

Mike leave this here a couple days as it is a Conquest specific engine problem.

Found a cracked piston in a machine along with the usual stuck valve problem in the front cylinder, intake valve had to be drove out which was replaced with a cleaned up used valve. The heads in this engine were replaced with new last year for the customer, I believed a lot of the problems were fuel related and we run startron, I also ran a bunch of 2+2 down the carb while running to clean the stems after repair.

After 1 piston and new rings in both cylinders at Busco we kept sticking valves, having what we had used chain lube as a lubricant to free stuck valves which did not last long( figured the wax), found some wd40 and freed them up better. The engine would run til you shut it down and then stuck valve, the engine has 30wt oil I plan to change now due to some extreme crosshatching I had hoped to cure.
So my question is might the lower wt oil cure this, will synthetic help with valve sticks or am I tearing it down again and cleaning and perhaps adding some clearance.

Just fyi, freed 1 valve leaving Busco started it and put in the trailer, today valve was kicked again before backing it out. Yes they are both the intake valves which had acted up, running super now with startron. Plan to suck fuel dry from the tank and start over.

Thanks, being lazy, Jim

Big Lebowski here.

Over the line!!!!!


The solution to the Kawasaki FD620D's infamous valve sticking problem(s.............) is to install stiffer valve springs all around. I've not done the conversion in a little while, but I would install valve springs from commercial duty slant single cylinder Honda GX engines. Poof... problem solved. Does running premium fuel and stabilizer help? Absolutely. But I've seen countless Conquests running said fuel and said stabilizer... same problem, but admittedly far less often.

The stiffer valve springs cured the problem just as easily as Yoda lifted Luke Skywalker's muskeg sunken ship in the Dagobah System.

May the force be with you.

I agree, The stiffer springs always fixed the problem in the John Deere Gators N 400's in the 90's

Same here. Those Gators were supercalifragilisticexpialidociously horrible machines. Made lotsa $$$ on them though.

I contacted both Argo/Kawasaki and John Deere many a time to inquire why on Super Mario's Green Earth the "engineers" had chosen to install what were basically miniaturized Slinkies as valve springs. The Answer? => INSERT ETERNAL SILENCE HERE <=

I don't deal with John Deere anymore, but the eternal silence from Argo is still going strong. And it ain't just about the valve springs either.

God bless you Mary Poppins.

Thanks guys, any ideas on the engine model or and single gx?

Its been a long time since I've done one but these boys set me up in the past. have the Dia and install height numbers, Your not runnin' crazy rpm's or lift so Ya won't need anything too fancy.



EC Distributing
2950 Hwy 48 South
Dickson, TN 37055
Phone: (615) 446-6807
Fax: (615) 446-9418

It's been a while since I invented the cure for "Kawasaki Sickness."

I'm not kidding. I am the one who found the solution to the infamous Kawasaki valve spring problem. Although to be fair, one must understand that Kawasaki lacks the intellectual prowess which I possess.

I believe I used valve springs donated from the incomparable Honda GX360 commercial duty air-cooled single cylinder engine. But I may be wrong as I've cured so many of the FD620D's over the years that my memory escapes me.

Regardless, the solution is unfathomably simple. Print out my cure for Kawasaki Sickness, head to your local engine rebuilder and in 5 minutes you will be armed with actual valve springs instead of miniature Slinkies.