Valve "stuck" in 525
 

Stock 525 with no more than 200hrs. Ran the boat for about 45mins at 4K. Blew a u joint that took out the transom assembly. So had to pull the motor decided it's a good time to do valve springs. Got the motor and drive back in the boat. Idled the boat for 30 mins or so. Went to take off about 300 yards at 4K. Motor quit. Got. The motor out and valve over off four a rocker arm swisted and push rod pushed up past the rocker. Mechanic got the head off took it to their head shop and supposedly the valve was stuxk in the guide. The valve did tap the piston. Now the only thing I can find on valves sticking is a leaky header. Before the drive blew I did have a header that was leaking on that head (found the leaking header when they test ran the motor on the stand). So my question is could that valve have stuck from the water that was leaking before the motor was reinstated? I did buy a new set of headers and put them on that motor so there was no water leaking into that head when the valve "stuck in the guide". Or is there more likely a issue with the valve spring job? Thanks for he help (I have pictures of the head as when the rocker and push rod were still in the head also have a picture of the top of the piston )

I've heard of the guid corroding where it's pressed into the head and squeezing the valve stem. Haven't seen it first hand but heard of it for what that's worth

Did they only replace valve springs? Or did they do head work and install new valve guides? If they did, maybe your valve to guide clearance is too tight.

These are bronze guides since it's an aluminum head

Just did valve springs.

if the valve stem did not get lubed during assembly it will stick in the guide.

Dex cool does a great job of corroding the sh!t out of parts.
Guess I should've said corrodes the head around the guide

If they Knurled the valve guides and didn't check fitment on that hole, they will warm up and stick.

Only thing that was changed is the springs. Everything is still original from merc factory.

Heads on or off when they changed springs?

Heads were on.

If someone could post the pictures for me that would be great. Might help a little bit

I've had a valve stick from a leaky header. Pulled the head. The valve hit the piston. Piston was fine. Replaced the valve and all was good.

I dont think the guide is exposed to the water jacket like it is on a GM iron head, which i believe its only the exhaust valve that the guide is exposed to the water jacket.

Sounds to me like maybe something went wrong with the spring replacement. Like, rocker nut wasnt tightened properly, spring coil binded, keeper wasnt in properly, etc .

Of course most mechanics arent going to tell you they messed up and have to eat the repair bill. Easier to say it stuck a valve from a header leak.

If the valve tagged the piston, then there isn't much doubt in my mind that it's stuck in the guide. That is more than likely an effect, not the cause. As Mild said, something probably went wrong with the spring replacement (which happens very easily when changing springs with the heads on) and the valve hit the piston, causing it to bend and hang in the guide.
Eddie

The last motor I tore down had a stuck exhaust valve kiss the piston. Exhaust manifold had a leak which corroded the valve stem and guide. Leaky exhaust can be one cause.

Alright another valve issue. Here are the pictures. The one with the twisted rocker is the first time along with the piston that got tapped. Other pictures are the most recent failure. Running 3800. Motor just shut right down. Head of valve sheared off. Destroyed the piston and head. Cylinder wall is all bear up. Picture of the whole head with all the other valves still in. One bank of plugs were white as can be. Any idea what is going on? <iframe width="480" height="360" src="http://s1381.photobucket.com/user/kevin_joseph2/embed/slideshow/Mobile%20Uploads"></iframe>

Is that the same cylinder with 2different failures?

No first failure was cylinder 7. Second failure was #8

How many hours on those rockers?

that I don't know. The first valve that stuck we pulled the oil pan and a rod bearing and checked out the cylinders. the motor looks to be basically brand new. It def is a rebuilt motor though I know that

Anyone know what brand the stock valves are?

Is the push rod on that rocker bent? Are the push rods the correct length. How does that cam lobe look? What does the lifter look like. I When you removed the rocker was it installed correctly. I've seen them installed with the center rotated 180 degrees. Do the rockers move freely? Check the bearings on that rocker. What shape is the mounting stud in?

Push rod is not bent. Push rods are correct length. Cam and lifters are in excellent shape. Rockers move freely, Bearings are good on the rockers. Mounting stud is in good shape as well

Sometimes crap happens.
I replaced a set of valve springs (only) and 2 hours later had a solid lifter crushed and it wrecked lifters, cam, oil pump, a valve, bearings, etc, etc.

Pretty common problem on the 525 EFI motor I just had the same thing happen replaced heads small small spot on a piston with the valve been hittiing piston .I have fresh heads on the shelf new springs new retainers I did it all this week Motor is now back in the boat runs perfect

Can the oil/cam sensor adjust how much fuel is allowed? Thought I read that somewhere. Anyone know? Thanks