STUCK VALVES

[ZANE]

Thought this might be useful information to somebody starting up an enigine that has been sitting for a long period of time.

I have a John Deere LUC two cylinder power unit that powers my Meadows grist mill that had been sitting at least a year since last started. I wanted to start it to crack 50 pounds of corn to feed to my big 4 chicken flock. After cleaning the plugs and digging into the high speed jet on the carburetor it started with the help of some starting fluid and ran good. I poured the 50 pounds of corn into the hopper and in about 10 minutes the corn was all cracked so I decided to let it run a few more minutes to clear out the grist mill. After about two minutes it began to sputter and puff smoke out around the intake of the carburetor where I had not tightened it up after working on the carburetor. It got down to hitting once in a while on one cylinder and finally quit. I tried restarting it with starting fluid etc and it would backfire and puff that intake smoke. Had absolutely no compression. Took the tapped cover off and found both intake valve stuck open. Thought it would be a simple thing to just pry the valves down. Nothing doing! I finally pulled the head and found both intake valves standing wide open. Could not push them down with my hand so got out my trusty air impact hammer chisel with a blunt tool and put it on top of the valve in the middle so as not to bend the valve. Got the valves to close but hard to move really. Turned the crank and they stuck again hard. I finally got them closed again and just continued to hammer and vibrate then with the impact and spray in WD40 till I could finally turn the crank and they would come up and go back down on their own.

I am thinking that there had to be some rust inside the intake manifold that came loose when the engine first began to run and got pulled up around the valve stems and finally locked them up.

I am going to take the manifold off today and sand blast it inside to make sure there is no more rust if in fact that is what happened???? I suspect that the alchol in our fuel caused the rust in the intake to form after sitting for some time. This is something that has never happened to any engine I owned in my 60 or so years of mechanic experiance????? Only thing I can think of to blame it on. Anybody have any other ideas of why this happened?????

Zane

 

[JMOR]

Sorry to say, Zane, but the EPA does not give a Rat's patotie about you or your chickens and would me made much happier if that old engine were melted down & shipped to China. In the mean time, mix about a quart of oil in every 20 gallons of crappy-gas (80:1) and maybe you can keep going awhile longer.

 

[mhb@ufe]

My brother was using his 841 and it started skipping and lost power. After checking everything else he pulled the valve cover and found 2 bent push rods. He called me and asked what might have caused this and my first thought was old gas. I asked him about that and he said he had some in a can that he had for a while and had dumped that in the tractor. The old gas gummed up two of the intake valve stems enough to stick them and bend the push rods.

Mark

 

[fireater]

a couple of cups of diesel fuel in the gas keeps them lubed up

 

[awhtx]

Mix a little MMO or ATF in the gas and crankcase oil to keep those valve stems free.

 

[MarkB_MI]

Assuming the engine was brought to operating temperature the last time it was run, any alcohol or gasoline left in the intake manifold should have quickly evaporated. It seems more likely water somehow got into the intake.

I always add a little Marvel Mystery Oil to my gas, which seems to help. Also, with single-cylinder engines, you should always turn them over so the engine is on its compression stroke so both intake and exhaust valves are closed. Obviously you can't have both cylinders on compression with a two cylinder, but if you can at least have one cylinder on its compression stroke it will help.

 

[john_Bud]

Zane, sorry to hear about your trouble. It may be due to alcohol in the fuel allowing moisture to collect. The gas alcohol mix is more corrosive than old gas ever was. I try to mix an oz of 2 cycle oil into all gasoline for old engines (128:1). The lubrication is supposed to help and I hope the oil helps to prevent rust. Can't say that it works, but I can say that it seems to help keep the rings free, the compression up and there haven't been any cases of stuck valves. I do the same to diesels to help increase lube with the high pressure new systems and the super duper low Sulfur fuel.

 

[juniur]

put stabil in your gas when you buy it . we have been seeing alot of auto engines that this happens to if they go unstarted for a couple months. have had to valve jobs on several . when the valves are removed there is a sticky varnish on the valve stems.its related to the "new" gas