BAD BAD day - HELP

Guys,

OK here is the story. I got the carb rebuilt in the boat and everything ran fine in the drive way. We tuned it and set the idle.

I finaly got a morning to run over the the lake and test it out. I get on the ramp, jump in the boat and try and crank her. She wont start. For some reason it looked like I had a weak battery. OK not a big deal. ran to get a battery. drop it in and get back on the ramp. After cranking it for what i thought was way to long it started.

I pull off the trailer and im going to the dock and I notice it making a light knocking noise.... I was pissed....

I ran it around close to the marina and the knocking continued but it wasnt consistant. It seemed stronger when the boat was n gear but idling. and light when the boat was out of gear.

so being scared of messing it up more i put it back on the trailer. I got back to town and checked the dip stick. it was milky....

I drained to oil....



Am I completely screwed? I need yalls opinion on what I should do next.

Im gong to try to up load some video to you tube. I think you can hear it if that helps..

at least you got the plug out without cutting the hose.

trouble free boating is mostly a fantasy only experienced for short periods if at all.

Have you considered adding horsepower? now is your chance.

Andrew,

I had water in my oil and it turned out to be one of plugs in the top of my heads had a pin hole in it.Water was getting thru. I know it is a long shot but an easy fix compared to the other options.

google video on water in 351

Whatever you do I would not run it again.
My symptoms were similar to yours at one point. I ran it because I already had intentions of scrapping the engine.

The flat tappets, will wear quickly, and that is costly. Just ask me.

Might be too late if it is already knocking.

ok so I’m guessing my best way forward is to build a stand and pull the motor? of do you think I can take the manifolds off and heads while its in the boat? I dont have an easy way of getting that motor out myself. I will need to source a local shop with some over head equipment.

I haven’t ever disassembled one before. Should be interesting. When I am disassembling I expect a lot of the sludge mixture to be present. What can I clean all this out with? I wouldn’t think water...

and yes manifolds and heads can be removed in the boat, just cover everything up so you dont make a mess. Do your best to start narrowing down the causes.

Yes, drain the oil and replace with new. I'd normally like to see you flush out the old oil and water and do another change, but until you figure out the knocking sound I'd hate to see you fire it up. You can pull all the spark plugs and spin the engine by hand to see if you hear anything and see if any water in the cylinders.

Water in oil can have a few causes like people described above, and catching it quickly like you did minimizes the chance the water does any damage. What we don't know is what that knocking sound is. If you could get that video up it might help.

I wasn't implying any power upgrades from you. Everyone is saying headgaskets, intake, exhaust manifolds or heads and then let's upgrade the heads while you're at it. I'm saying let's find out where the problem is first before you start pulling this thing apart.

Yes, change the oil as you normally would. You may end up doing it a few times before this is all over so be patient. You want to have clean oil in there so we can get the best data we can. Pull the plugs before you start it. Is there any water in the cylinders? How fast does the oil turn milky? To do a compression test you should have the engine warmed up first. Is it milky after that warm up? We still don't know for sure what engine this. I assume a 351.

A leak down test you get each cylinder to the compression stroke and then put compressed air into the cylinder and listen to where the air is escaping at. Heads, intake, block, or exhaust. It can be more accurate than a compression test but a compression test is a good starting point as all you need is the compression tester that's easily purchased about any place. Not everybody has easy access to some compressed air tanks.

Some of the usual suspects in these cases are the exhaust manifolds letting water into the cylinders. A blown head gasket. A cracked head. The 351 (if that's what it is) has had several cases of a cracked intake in the water passage on the underside of it. Everybody assumes the worst(a cracked block) but I think that's really pretty rare under the type conditions that you're descibing.

Let's do the compression test and if possible, a leakdown test and see what we got first. Then we can worry about the next steps.

yes, the semi random thump noise is what I am talking about. you can hear it good at second 54

Sorry Dave,
I can't watch the video here at work. Video sharing sites are blocked from us. I won't be able to listen to it until I get home tonight.

By what you're describing, it's not related to the one-to-one rotation of the engine. Crank or cam. If that's true, I think it's a good thing. If you're hearing the sound every 4-5 seconds and it's still random, I gotta believe that the rotating assemblies are OK or you'd be hearing something more consistant with every crank or cam rotation.

I personally think that you pull the plugs to see if there's any water in any of the cylinders and do a compression test. Maybe do the compression test cold at first to see if there's anything obvious that jumps out at us. Do this on the trailer with a water hook up in place and pressurized at that time (aka Fake-A-Lake). With the plugs pulled and cranking the engine over for the compression test, if you have an exhaust leak that's bad enough, you might get water spitting out a cylinder or cylinders. That would a good thing in the overall scheme of things. A simple (or not so simple) exhaust gasket or cracked exhaust manifold).
Then again, you might have to get the engine warmed up and the thremostat open before you'll see the leak. If that's the case, you're only option is running it. Knock or no knock.

No matter what, I feel that you need to find the source of the water intrusion before worrying about the knock. I'm guessing one fixes the other from the problem history and description but I'm certainly not an expert.

Hey y'all, went and did the compression test this morning. Here are the results
1-130
2-130
3-130
4-140
5-125
6-115
7-110
8-120

Thoughts? Didn't have all my tools to get those exhaust manifolds off. I'm guessing that is the next step?

Update..... Nothing to update other than I'm married, I have a dog now, and I bought two (new to us ) cars. So having fun with the f 250.

Now, the reason for the post. I was honestly thinking of just buying a rebuilt motor from thunderbolt in Houston and having the swap the damn motors and be done with this boat. But after a lot of searching and chatting with buddies which is always fun, we are diving in to this issues tomorrow. Plan is to take the heads off and inspect. Hope for a bad head gasket on the port side. If that's the case I plan on taking the heads in and getting them checked.

Theory. I can't mess it up and if I do I was willing to buy a new motor anyway.

You guys have any advice? I'll be on tonight but everything should be on this thread.

Honestly without this site I would have sold this boat for a huge loss months ago. Love reading you guys posts and looking at pics more!!!

I took a lot of videos when I had the boat running last. After going back a watching I honestly think you are right. I don't really hear it from the motor in the video more the trans side of things.

I could be going about this the wrong way but I think opening it up and inspecting if anything won't cause any harm and could shed light on the water in the oil situation

With the low compression in 2 cylinders it seems I will find the issue pretty clear

Quote from the thread starter first post:
"I finally got a morning to run over the the lake and test it out. I get on the ramp, jump in the boat and try and crank her. She wont start. For some reason it looked like I had a weak battery. OK not a big deal. ran to get a battery. drop it in and get back on the ramp. After cranking it for what i thought was way to long it started."

To me, this one statement is a neon sign indicating a hydraulic bind. 90%+ chance its a riser or manifold. A simple gasket will do it.


As for the engine, drain the oil and fill it up (full) with diesel fuel until you tear into it. This will keep it from rusting internally while nothing else is being done.

Gahh looks a little rough. Did you see any point that looked like would have been leaking water by the headgaskets? Check thoroughly around the cylinders and mostly where you want to look on the head gasket would be on the top side making a trail from the water jacket holes into the lifter valley. The ends of the intake manifold where the water crosses over are also big suspects in water intrusion. Take the rises off the exhaust manifolds and take a look there too.

Take the heads to the machine shop and have them magnafluxed to check for cracks. Someone has been in there before because they used the paint on the rockers to mark which side or head the rockers came off of.

Might want to invest in a good straight edge and a feeler gauge to check the block surface once it is cleaned for flatness. Like I said before, if the heads and all check out ok make sure to flatten the surfaces of the risers with a file and install new gaskets on both sides. Stick it all back together (preferably with a fel-pro marine gasket set). Make sure you attempt to clean out any residual oil you see anywhere visible. Like stated above don't freak out if the fresh oil turns milky when you first run it. That may be left over water and oil from before. You might need 2 or 3 oil changes to clean it out.

Stick it back together and fire it up.

Also, if it were me I would have the machine shop go ahead and clean up the heads, new valve job and new seals/guides. If you do this and the engine is trash you can still use the heads on another engine or sell them. If they are off you might as well do it. Some of the holes were slightly down but it may be because of worn valves? Either way it won't hurt or break your wallet.