154 Stuck Valves

Mon Feb 11, 2013 6:01 pm

:lost: Hi All
Did you ever buy think you were getting a great deal and find out later it wasn't such a great deal? Well I have been looking for a snow plow for my 185 for a year or so. Don't know why for sure, we usually plow snow with a truck, but I kinda wanted one for the fun of it. So i found a 1969 154 for sale with a belly mower and a snow plow. Talked to the guy, he said it hadn't run for about 3 years cause it leaked gas so bad out of the carb. So I bought it figuring I would keep the plow and resale the tractor after I fixed the carb and got it running. Tractors in average to better average shape. I will post a few pics soon. Got it for what I thought was a good price, $850 and brought it home.

So tore the carb off, and guess what, someone had broke the idle tube off. AHHHH! $30, alot more than I think they are worth. Another $50 in rebuild stuff and gaskets and i got the carb mostly rebuilt. Still leaks a little gas when you crank the motor. The top half doesn't seal real well with the bottom. So have to work on that. But good enough to try and start the old girl.

After trying to start it, determined there is no spark. So the plugs looked original, so I bought new champions. Still no spark, but I figured what the heck when I have the plugs out I should see how much compression the tractor has. Bad got worse....cylinder closest to tractor seat had 30# on first revelution and max at 90# after 3 revs.

Anyone know if that is typical? But I am thinking not bad for an engine that sat for 3 years. The second cylinder had zero # pressure. Really bad and the front cylinder had zero #. Now I am thinking my great deal is not so great.

SO I pulled the valve cover off, and with no surprise two of the valves are not moving down.

I am open for suggestions here, but I am guessing my next step is to pull the head and try to remove the valves and clean them up or replace them. Let me know what you guys think. Also, would you try to clean the valves seats up in the tractor or pull the motor out and go all the way in the rebuild. If I have to pull the head I will check the bores to see how much they are worn.

Re: 154 Stuck Valves

Mon Feb 11, 2013 6:48 pm

Spray the valves with PB blaster Liquid Wrench, etc. Work them up and down, with a pry bar. Put a little oil in each cylinder. Prime the oil pump before you try to start it. File or replace the points. you should be good to go then

Re: 154 Stuck Valves

Mon Feb 11, 2013 7:19 pm

spgeid wrote:Cylinder closest to tractor seat had 30# on first revolution and max at 90# after 3 revs. Typical?
Typical. Usually do or take 5 compression strokes to get an accurate reading per cylinder test.

Follow Boss Hog's suggestions. With hood off you can easily reach the spark plug holes. Obtain one of the plastic tubes that comes with some aerosol containers. Try to spray solvent under each valve head. Inside the valve spring chamber, spray the heck out of each valve stem.

I would free up the valves, get the engine running. Seafoam in fuel and crankcase. Operate the engine for a while, perhaps 6 months or so to determine how it ran and condition.

Re: 154 Stuck Valves

Tue Feb 12, 2013 7:44 am

Thanks guys! that makes me feel a little better. I tore most of it apart last night. I will give the Pb blaster a try before I take the head off her.

Re: 154 Stuck Valves

Tue Feb 12, 2013 8:58 am

Not much to see with the head off. Pull the valve cover (behind the carb manifold) and slide the cover down so you can see the valve stems. The cover doesn't come all the way out without pulling the carb, but it slides down far enough to get out of the way. Use a piece of wood or a soft screwdriver to work the valves down that are currently stuck in the up position. Use a good penetrating oil.

Again, good advice from others with adding Seafoam to the oil and fuel and giving it a good workout.

Re: 154 Stuck Valves

Tue Feb 12, 2013 9:28 am

If that is all you have for problems you did good.

Re: 154 Stuck Valves

Tue Feb 12, 2013 9:59 am

My experience is that valve operation is key to having a healthy engine. I recommend removing the head, cleaning away the carbon, freeing-up the valve stems, inspection and servicing worn valves and seats and related hardware and making an assessment of the cylinders and piston rings while they're exposed. You'll need a valve spring compressor tool to remove the valves. Once you determine what needs replacement, (re-)set the valve clearances and you'll have a good runner. The resources to learn about this engine and how to evaluate and service it are available on this website.

Re: 154 Stuck Valves

Tue Feb 12, 2013 11:05 am

Just do as Eugene and I have said, there is a 90% chance that the head will not need to come off. Cubs are like Golf, The guy that has played 3 times will give the guy that has played once Golf lessons :lol: :lol:

Re: 154 Stuck Valves

Tue Feb 12, 2013 11:53 am

Yup. What Boss Hog said. You may find that the engine in petty good shape. Just get engine running, fluid change, tune up, perhaps flush the block. Operate for a period of time - this will provide an opportunity to evaluate entire tractor.

Typically the Cub Low-Boy 154 is/was used as a lawn mower. Guessing, other than a bunch of piddly things, tractor is in pretty good condition.

Re: 154 Stuck Valves

Tue Feb 12, 2013 8:05 pm

For $850.00 not only did you get a good deal but you stole that 154. I am not a huge fan of them but for a mower I don't think they can be beat especially for estate sized properties.

Gotta agree with David and Eugene. You DO NOT have to take that head off to get these valves free. I have just been through this with my '47

Subject: Compression problem

Rudi wrote:Stuck valves :!:

Why do I know this :?: Dealing with the exact same problem with my 47 - Granny - here is the thread - Stuck Valves. Pull the plugs on 2 and 3, pour in 1 tablespoon of oil, rotate engine by hand a couple times. Take the side valve cover off. Spray the valves/valve springs and tappets with your favourite penetrating oil. I like Nut Buster and Loctite's Solvo-Rust. Rotate the engine by hand with/without hand crank again but while watching the valves functioning. You should see whether it is exhaust or intake valves that are sticking. Take a standard screwdriver and very.. very gently tap the offending valves once or twice. I used a dead blow mallet to reduce the shock to the valves. Spray the valves in the spark plug holes with your favourite penetrating oil. Rotate the engine by hand a couple times hopefully twice each cycle. Continue to do this until the valves drop and drop they will. They are just stuck up because of carbon/oxidation.

After the valves have dropped, add another tablespoon of oil to each spark plug hole and hand crank the engine again. When you feel the valves are moving freely, add some SeaFoam to both the gas tank and the crankcase according to the directions on the label. This will help clean the valves/valve stems and guides. It may still take a bit to get the engine to fire up, but this is the first step.

Suggest you use a piece of wooden dowel instead of the screwdriver. Less chance of damaging the valve itself. Just keep tapping, lifting and spraying until the valves travel full cycle by themselves when rotating the hand crank.

Re: 154 Stuck Valves

Tue Feb 12, 2013 8:30 pm

I 'd listen to Boss , Rudy and Eugene for sure, they have always given me great advice.

Re: 154 Stuck Valves

Tue Feb 12, 2013 8:38 pm

Joe Malinowski wrote:I 'd listen to Boss , Rudy and Eugene for sure, they have always given me great advice.
Rudy and Eugene for sure. Not so sure about Boss, even though he said it first. :oops: did I say that.

With the hood off and spark plugs removed - with light you can see the edge of the stuck valves. After soaking in solvent, bit of hard wood dowel to tap down any valve still sticking. May take a few or number of tries to fully free up stuck valves. Tap down, solvent spray, rotate engine to lift/stick valve - tap down. Sat 3 years, shouldn't be stuck that tight.

Re: 154 Stuck Valves

Tue Feb 12, 2013 9:29 pm



Re: 154 Stuck Valves

Tue Feb 12, 2013 9:44 pm

I played golf once.... Only once took a head off (I could explain the mushroom theory).

I go with pull the valve cover and get them lubed and free. Change the oil and filter (gets whatever you used on the valve out too), prime the oil pump and give it a shot.

Good cheap tool to have is a light you put on a plug wire. I am with Boss on the points.

There is a lot of good info on carbs here, try a search.

My guess is you got a good deal. Better deal if it was stored under cover.

Re: 154 Stuck Valves

Tue Feb 12, 2013 11:01 pm

Great advised from all. Thanks Guys. I got the carb and exhaust manifold off. SO lots of room to work on it now. One of valves came loose right away with one spray and tapping it down. The other is very tight. I can get it to come down but it takes a lot of torque on the front pully to move it back up and then it sticks again and has to be tapped down again. I will soak it for a few days and see if it gets any looser.