www.iFourWinns.com

Another clue -- it gets more intruiging by the day -- I looked at the spark plugs and one of them was completely fried. The ground electrode was toast, in fact had burned off.

Not good.

That, coupled with the non-compression, leads me to fear the worst. Cannot figure out *why* a cylinder would run that ot without pinging...could be anti-knock feature of the engine, masking the severity of the problem. I am hoping that something, somewhere just got stuck and that I didn't burn up the piston.

Pray for me, gang.

Mark

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Four Winns 1996 Sundowner 205
5.0fi/SX engine (Volvo Penta)

Don't assume the worst yet. Your problem could be just a bad plug.

If you can get the compression gauge then do the test if not check w/ the guy who rebuilt the engine and have him confirm the 0 on the #1.


Was it the same people who diagnose the no compression on #1 the same ones that showed you the bad plug?

_________________
Walter

2003 248 Vista - VP 5.0 GXi
2009 Toyota Tundra SR5 5.7L 4x4

Walter, et al,

Nope -- the *generic* marine shop was the one who wanted to pull the head off. Today I towed the boat to my guy (more $$ guy)(who did the rebuild 2 years ago). As I told him what was going on I noticed a rag on a cockpit seat. Inside were all the old spark plugs (which had been pulled by the first shop). He looked them over saying, "this looks okay, this looks okay, this looks okay..." Then we came across one whose electrode was fried. Cooked. "That's bad," he said. "Not good. It looks like it got so hot it burned the base of the plug."

He said he'd get new plugs and run his own compression check. He was amazed that the shop who pulled the plugs didn't label them so he'd know which chamber the bad one came from. "Makes detective work a little easier," he said. But no worries, he'd find the cylinder and find out why it wasn't working. His big concern was that it got so hot it fried the piston. I have to say there was little of the little electrode left. There was no gap to measure, it was black, cooked, gone.

He asked if I heard a ping while it was running, but I said no. I do remember hearing "tics" while the engine ran, but that wasn't something I thought was too unusual. But the fact that I recall it tells me it was something out of the ordinary -- I guess I am tuned to what it *should* sound like. Still, it ran fine and continued to run fine until I came off the throttle as we pulled into the marina and I noticed the engine was running rougher than usual. Still didn't alarm me, the area we inhabit is famous for questionable fuel. I figured I'd burn it off and fill up at a different marina and the problem would go away. Never got the chance.

PS -- The engine never overheated, and the oil pressure was steady.

_________________
Four Winns 1996 Sundowner 205
5.0fi/SX engine (Volvo Penta)

Lets see what his compression check shows.

An overheated spark plug can happen for many reasons. Some more expensive then others. Perhaps they simply used the wrong plugs. Lets see what his compression test results are. Let us know.

_________________
Walter

2003 248 Vista - VP 5.0 GXi
2009 Toyota Tundra SR5 5.7L 4x4

UPDATE *** UPDATE *** UPDATE *** UPDATE ***

You probably thought I forgot about you. Well, I did not. The marine shop has been so busy leading up to Labor Day that they could barely look at the engine until last week. Here's what I know.

Something in the injector caused it to run lean.
It got so hot it melted the spark plug AND the intake valve, taking the injector with it.
The piston/cylinder is okay.

So I am in need of a valve job. It's not materials that is killing me, really, it's the labor.

Question is: What caused it? He doesn't have much to work with. He is bringing in a friend who works with fuel injection to scope it for him and, perhaps, learn what is causing the problem.
He does not want to button it back up and have it happen again in 3 years. But he admits it is an obvious problem with the timing that is "elusive."

I did fuel up at a dock just before this happened. Water in the gas? (It rained the night before, not that it has anything to do with it.).

It is a Ford 302 engine (Mustang) which he says it's pretty straight up basic, but can't find the key to the cylindar running hot. PS. It was not the same one I burned up 3 years ago. (Slightly different problem.)

that's the update. More when it becomes available. Stay tuned.

_________________
Four Winns 1996 Sundowner 205
5.0fi/SX engine (Volvo Penta)

Could it be as simple as a failed injector? Very sorry to hear this... but glad it isn't worse.

_________________


Mike
2005 Four Winns 230/240
VP 5.7GXi/DP
1998 F-150 XLT
Boat Pic

I would suspect that the intake manifold is warped or most probably the intake manifold was torqued to tight, im going off memory here I think the torque spec is 18 to 24 ft lbs here is the problem they need to be torqued to 12 ft lbs or they wont seal correctly which causes an air leak which makes a cylinder run hot. The reason I say this is I rebuilt a 302 and when I was doing the engine break in I had a simular problem a phone call to fel pro
( the gasket mfg ) they said the torque spec was 18 to 24 but to do a 12 lb
I did and it cured the problem.
P.S I went through 3 gaskets before I called fel pro the 4th was a charm.
Hope This Helps Take Care Gregg

Along the same train of thought... I've worked on many 302's as well. The thing that helped me the most was by heating up the intake bolts (on the grill) to about 300F immediately before installing. The idea being as they cool down, they shrink just enough. I had similar problems before trying that, and haven't had one since.

Your problem may have been as simple as a partialy clogged or poorly functioning injector. Did you replace the injectors when the motor was rebuilt last? Did the same cylinder get hot as last time? All good questions. Remember, running too lean can cause overheating as well.

_________________
Walt B
"Debt-Charged"
Black '07 H210SS
6.2L Bravo One turning a 21P HIFive
Wakeboard Tower with Perfect Pass Stargazer version
Missouri River; Kansas City, Mo.

Now the conclusion to our story:

The head was lifted off and it was found that the #5 Valve had melted, disintegrated. The spark plug had also melted. But the piston had not been harmed (thank goodness). Somehow the cylinder ran lean.

What was the cause? No one could tell. It was, and still is, a mystery.

Fuel injectors? We pulled them all and sent them out to be cleaned. They found nothing out of the ordinary, their sprays were nominal.

After some machine work we put the engine back together and ran oscilloscopes on the system. Nothing out of the ordinary EXCEPT we were given advice to replace the cap, rotors and wiring just because they were now 12 years old and, in a fuel injected system, can be susceptible to odd conductivity causing problems such as mine. We replaced the cap with new copper plug posts – where before there had been aluminum. We also got rid of the aluminum engine cover -- was there more for cosmetics than anything else, or so I am told.

Some machine work on the valve and new plug wires, plugs, and the engine sounds better than it has ever sounded before.

My guy tells me that he cannot say for sure what caused the valve to melt. We went through every possibility – water, bad fuel, fuel pump, injectors, plug wires, shorts, faulty connections, on-board computer – none of them came back positive. It will make for some nervous times on the water, but we are expecting a good weekend here in Oregon and I am going to take her out and give it a go on Saturday.

Thanks for all your advice. You are appreciated more than you know!

Mark (Picture of our last ride before the work -- just west off Orcas Island, WA.)

_________________
Four Winns 1996 Sundowner 205
5.0fi/SX engine (Volvo Penta)

Sounds great Mark. Thanks for letting us know the result. Hope you have a great weekend and that the fix was not to heavy on your pocketbook!

_________________
Walter

2003 248 Vista - VP 5.0 GXi
2009 Toyota Tundra SR5 5.7L 4x4

UPDATE: She is back in the water after a valve job (This was actually done last winter and now I am shaking her down). Everything SEEMS to be fine BUT I suspect the engine is still running a little lean: From 75% throttle to 100% is very little difference in power or torque.

QUESTION: Can a shop CHECK to see whether ian engine is running lean? Is it a major operation?

Am thinking I might want to replace the fuel pump, too, just to be sure. Have abig trip coming up.

Mark

The AIRWAVE at Roche Harbor, San Juan Island, Washington, USA

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Four Winns 1996 Sundowner 205
5.0fi/SX engine (Volvo Penta)

Maybe. It would have to be an EFI engine to put a scan tool on it though. If it's carbureted, no.


What is your WOT RPM and GPS speed?

What did it turn (RPM) before you had the engine worked on?

What is the RATED MAX RPM for that engine? (from the owners manual)

Why do you think you need to replace the fuel pump?

EDITED because I was finally able to go back and read all the previous posts!

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1987 Four Winns Liberator 211, formerly OMC 460 King Kobra powered, replaced in 2006 by a 1997 Mercruiser 454/Bravo III

Wow that is an interesing story.....I had something similar (but with less expensive results) occur with my old 88 FW...the engine was OK when we first got it, but the next season it would not plane out the boat...I tried everything I could think of but would up taking it to a very good local OMC shop...they found that the anti siphon valve on the tank was corroded, restricting fuel flow and the mechanic said it was good that I didn't try to keep running because the lean mix would have burned out the valves....that and a carb rebuild and it's been fine for 5 years...
I always check the color of the spark plugs after running it at speed at some point...you can tell much from inspecting them... they should be a light brown...grey is OK too..not blistered white...if you get that you have either a lean condition or a vaccum leak which is what happened in your case....I'd be checking these plugs frequently to make sure all is Ok, if not go back and check the basics again...Good luck the boat looks nice!

BTW my old 88 4.3 is still running well....21 years old....
Finally...make sure you use premium gas... make sure your timing is not too advanced...and make sure the boat is not over-propped...that can put an unreasonable load on the engine...I found that my boat peforms much better with a 15x17 than the 14.5x19 it came with....

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

This is strange, I couldn't read all the previous posts until I logged out.....


I went back and read thru the thread and I would say that you had a serious detonation in that cyl. (Maybe due to a lean injector) Detonation doesn't always melt/break pistons. It can burn valves, plugs, pistons, though.

Did you replace your injectors or flow test them when you had the engine rebuilt? If you didn't, it may still be partially plugged. Even if you did you might check them again.

Because the high loads on a marine engine (much like an aircraft engine) The damage is usually "done" before you know it (or can prevent it) when there's a detonation event.

Also, you don't always hear it.


Put a gage on the fuel rail and check the pressure. If it's where it needs to be you probably don't need a fuel pump.

"Prop" it so the engine turns MAX rated RPM when the boat is loaded where you always operate it. You don't want the engine turning to slow at WOT....(lugging)

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1987 Four Winns Liberator 211, formerly OMC 460 King Kobra powered, replaced in 2006 by a 1997 Mercruiser 454/Bravo III

Stats/information:

1996 5.0L SX Electronic Fuel Injection
Volvo Penta Drive
Prop: 4 ¼ X 21 (same prop size since purchase)

Before engine rebuild:
RPM at WOT is at or slightly over 4000. GPS speed 47mph under ideal (flat) conditions.
After engine rebuild:
Same RPM, about 43mph – although water conditions have not been ideal. But about the best I could pull from the engine.

Maybe 4mph is nothing to quibble over. It just *feels* different.

BTW – I rarely run at WOT speed. I think under good circumstances here in the NW I can maintain 3000-3500rpm (30+mph) for only a few minutes at a time (mostly rivers and lakes), if that. But during my trips to the San Juan Islands in Washington I find opportunities to run at almost full throttle for extended periods (30 minutes or longer)(with frequent throttle-downs for wakes and vessel traffic) when conditions warrant. But it was during such a trip that I suffered the valve burnout last year. It occurred after fueling at a dock. I asked some other mariners who used that dock regularly if they had any problems, and it was negative – so fuel might just be a coincidence.

OMC manual: Full throttle operating range 4200-4600.

Fuel filter idea thought comes from a mechanic who says dirty filters might make the boat run lean. However I get the boat serviced (winterized) every year. So I am certain they check that.

Lou, you make an interesting statement about premium gasoline which will prompt me to start another thread.


At rest in Friday Harbor, Washington

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Four Winns 1996 Sundowner 205
5.0fi/SX engine (Volvo Penta)