Cracked exhaust manifold, and then something stupid happened...

OctoberSea

Seaman Apprentice
Joined
May 27, 2009
Messages
30
Hi all,

5.7l Gi, 1996, TBI. Putting my frustration and subsequent embarrassment aside, here's the short roundup of a crappy day yesterday. Cracked an exhaust manifold, 4 port cylinders filled with saltwater. Within a few hours I pulled all plugs and cranked the water out. Following my mechanic's advice, I poured a modest amount of oil down the throttle body, and sprayed the inside of the cylinders with WD-40. While spraying the very last cylinder, the little red straw popped off and - I THINK, but am not certain - that it was sprayed right into the cylinder. There's hardly any space to look around and get any sense whether the %@%#$! straw is or isn't lying in some crevice in the tightly packed hoses, wiring, and motor. I'd say 70-30 that the straw is inside cylinder 8.

In probing my misery just now in the driveway, I was encouraged that replacing the manifolds and risers myself is a very do-able job. But I know that I need to confirm whether that &@#^$% straw in in cylinder 8. Should I even attempt pulling the cylinder head myself to try to save this boat, or is this something much better left to a real mechanic?

I'm a decent DIYer, but not very advanced... I am not a mechanic. I have my Seloc manual, and I can generally figure things out and follow instructions - I like fixing things myself, but am mostly motivated by not paying a marine mechanic $90/hr. I don't have a ton of to put into this, and baby #3 is on the way... so if I can't salvage this myself, I'm going to have to cut my losses and try hard to sell this boat as a project.

Thanks in advance, fellas. I really appreciate the help.
 

Don S

Honorary Moderator Emeritus
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Aug 31, 2004
Messages
62,321
Re: Cracked exhaust manifold, and then something stupid happened...

Don't worry about it. That little piece of plastic is not going to hurt anyting ane will blow out the exhaust very quickly.
 

dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,333
Re: Cracked exhaust manifold, and then something stupid happened...

first thing you need to do is get rid of the Seloc manual, you would be better off having your third kid fix the boat for you.

beg, borrow, or steal a boro scope or a fiber optic camera to look into the #8 spark plug hole for the straw

i would bet that a local repair shop would even look in the cylinder for you for no charge, it will only take a few minutes to verify if the straw is there

probably won't be that hard to get the straw out if it is in there

turn the motor over SLOWLY by hand, in SMALL increments to get the piston to the top of the cylinder and retrieve the straw
 

Bifflefan

Commander
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May 27, 2009
Messages
2,933
Re: Cracked exhaust manifold, and then something stupid happened...

The straw is about 6" long and the most stroke you have is 4". there for 2" of the straw would be hanging out of the plug hole, if it was in there. Also the angle of the plug hole is (likely) to great for the straw to have just fallen down there.
Id bet that its in the bildge and you just cant see it.
Even if its in there, if will burn up and go out the exhaust, so no worries.
 

wca_tim

Lieutenant Commander
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May 28, 2007
Messages
1,708
Re: Cracked exhaust manifold, and then something stupid happened...

trust me, at combustion chamber temperatures, that straw will easily burn fairly cleanly... not an issue.
 

OctoberSea

Seaman Apprentice
Joined
May 27, 2009
Messages
30
Re: Cracked exhaust manifold, and then something stupid happened...

Wow... thanks a bunch. I'm encouraged - at least about the straw. I was concerned that if it were in there (thanks, bifflefan, for putting the math to it - that's reassuring).

How fast do I need to move on the exhaust system, so I can fire the motor back up and blow out all the oil, residual water, and that straw? Am I at high risk of damage here? I live in Juneau, AK, where parts can be tough to come by and slow to arrive. I'm hopeful that I can find the manifold/riser kit locally, but if not it could be a week.
 

meesh

Petty Officer 1st Class
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Aug 24, 2008
Messages
256
Re: Cracked exhaust manifold, and then something stupid happened...

I would get it running as soon as you can. It sounds like you oiled it up real well, but your post did say salt water.
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: Cracked exhaust manifold, and then something stupid happened...

Wow... thanks a bunch. I'm encouraged - at least about the straw. I was concerned that if it were in there (thanks, bifflefan, for putting the math to it - that's reassuring).

How fast do I need to move on the exhaust system, so I can fire the motor back up and blow out all the oil, residual water, and that straw? Am I at high risk of damage here? I live in Juneau, AK, where parts can be tough to come by and slow to arrive. I'm hopeful that I can find the manifold/riser kit locally, but if not it could be a week.


Well, you need to get the thing turning pretty quickly.

You could unbolt the manifold and just run the engine a few min to "clear" the cyls.....( cap off the raw water lines to the manifold and riser.....and make absolutely sure you run the blowers and have no gas sitting in the bilge:eek:)


I'm not going to be up there until next month or I would just bring you the "stuff".......

I can just see myself going thru airport security with a set of manifolds and risers
toothlessgiggler.gif
 

myoldboat2

Petty Officer 1st Class
Joined
Jun 3, 2007
Messages
303
Re: Cracked exhaust manifold, and then something stupid happened...

i agree that it's probably not in the cylinder, and if these guys say it won't hurt anything, i believe them. being the curious type, i would try to see if it was in there. if you can't borrow a boroscope and the little claws that some of them have, maybe you could clean out your shop vac really good, tape some tube on the end that fits tightly over the plug hole and see what happens. it might pull out the straw or move it so that you can see it. if the shop vac is empty, work the hose (or an attached smaller hose) down into the bilge and see if you catch a straw.
 

OctoberSea

Seaman Apprentice
Joined
May 27, 2009
Messages
30
Re: Cracked exhaust manifold, and then something stupid happened...

Thanks, guys. Luckily I have some flex this week, so I hope to pick up the parts tomorrow morning and spend the day getting the new manifolds and risers installed. I'll definitely snoop around more in the bilge, as best I can. I've got a bunch of clean up to do in there anyway, with having blown water and oil all over the place.

Any particular pitfalls I need to worry about with this job? Having looked it all over and read through the manual section twice, it seems pretty straightforward... just focus on getting a good clean surface on the engine block for the new gasket?

Will report back.
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: Cracked exhaust manifold, and then something stupid happened...

Yeah, they're not all that hard to install. If your new gaskets are "silvery" they go on dry.....no sealant. use a torque wrench and don't over-tighten.
 

OctoberSea

Seaman Apprentice
Joined
May 27, 2009
Messages
30
Re: Cracked exhaust manifold, and then something stupid happened...

Got it done. Everything seems good. I searched and searched, vac'd, and searched, the grabber-tooled, used mirrors, and lights - never found the straw, in or out. So, after about 10 guys told me it would be ok to burn that straw if it were in there, I did it. The new manifolds/risers are great, and all systems seem good. Changed the oil twice, and have new plugs installed. Switched the original stud posts to #8 steel hex bolts, because it was a pain to have to back out each of those 12 studs with a mini pipe wrench (still, it was better than the alternative - cutting into the deck). Added some seafoam to both the gas and the crankcase oil to help clean everything up after this mess.

Thanks all for the input and help. The boat's back in the water now...
 
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