crossflow v4 rust in the lower left cylinder?

[GatorMike]

A few weeks ago I posted about my 115 Johnson that was frozen up tight. I soaked it for days and still couldn't free it up. Well I finally got around to removing the powerhead and opening up the crankcase. I started inspecting things with a flashlight. I expected to find all kinds of rust but everything looked pretty clean, just a little surface rust here and there. Then I shined the light into the lower left cylinder and it looks pretty rusty in there from what I could see. A lot of what I am seeing could just be sediment from other parts of the engine since I have over the past couple of weeks poured a gallon or two of PB Blaster & Marvel Miracle Oil in the thing trying to free it up but I think it is rust.

I haven't removed the crankshaft yet since I don't have the socket to remove the rod cap screws. Gotta run get one later today. Anyway before putting anymore time and money into this thing I thought I would try to determine how saltwater could have gotten into that cylinder and whether this powerhead is fixable. Any Ideas on how many different ways water can get into the crankcase side of the cylinder?

 

[tashasdaddy]

Re: crossflow v4 rust in the lower left cylinder?

head gasket, exhaust gasket, cracked block.

 

[Dhadley]

Re: crossflow v4 rust in the lower left cylinder?

There are several ways water can get in there. We know there is water in the bottom cylinder and most likely the bottom main, right? How's the top main?

 

[GatorMike]

Re: crossflow v4 rust in the lower left cylinder?

There are several ways water can get in there. We know there is water in the bottom cylinder and most likely the bottom main, right? How's the top main?

I assume you are asking about the main bearings? I haven't taken the crankshaft out yet so I haven't pulled the bearings out yet either, I think they come out with the crankshaft?
The upper bearing feels alright to rotate it but I can't really tell anything about the bottom.

I will add some information at this point see if it helps any on a diagnosis. I always clean the spark plugs before every major trip and do a compression test regularly just for my own information. The last couple of times I had it out I notice rust on the lower left spark plug tip, stupid me suspected a problem but didn't bother to fix it at the time. I used it for a week last April and when we got home from vacation the compression was excelent. If I had known the boat was going to sit for 9 months I would have fogged the motor and investigated the rust on the spark plug problem. Lesson learned.

 

[ezeke]

Re: crossflow v4 rust in the lower left cylinder?

You could have gotten water from a bad exhaust gasket, from a bad seal on the cylinder head, from storing the motor tilted up, from having too much water pressure on your flushing device, or from a cracked cylinder.

The fact that the water is on the #4 cylinder makes the exhaust gaskets a more likely possibility.

 

[GatorMike]

Re: crossflow v4 rust in the lower left cylinder?

I don't want to just assume this was the problem but, inside the inner exhaust cover there are 2 filler blocks that attach with 3 bolts each, the left block is broken around the lower bolt. Could this have been the problem? Like I said I don't want to just assume that was the problem without looking at other potential causes.

Came back to edit this because I don't think water circulates inside that inner cover anyway does it?

 

[ezeke]

Re: crossflow v4 rust in the lower left cylinder?

.....2 filler blocks that attach with 3 bolts each, the left block is broken around the lower bolt. Could this have been the problem? Like I said I don't want to just assume that was the problem without looking at other potential causes.

Came back to edit this because I don't think water circulates inside that inner cover anyway does it?

Very, very unlikely that the filler blocks have anything whatever to do with a water problem.

The problem comes from leaking seals between the exhaust manifold and the exhaust outer cover or between the exhaust manifold and the block. When replacing, be sure to use new gaskets, an appropriate sealer, torque to spec and re-torque after running.

 

[Dhadley]

Re: crossflow v4 rust in the lower left cylinder?

If there is no water on the top bearing then you can rule out water injestion. In that case you can follow Ezeke's suggestions. And those blocks will have nothing to do with leaking water. Actually you don't even need them.

 

[GatorMike]

Re: crossflow v4 rust in the lower left cylinder?

It is a bit worse than I thought, there is some rust in all cylinders just took the cap screws off the top two piston rods which were in the all the way in position and it took some taping with a block of wood just to get the pistons to move. If I remember from the last time I rebuilt one of these (several years ago) the pistons almost fall out when you remove the cap screws?

 

[GatorMike]

Re: crossflow v4 rust in the lower left cylinder?

I think my best bet at this point is once I get this thing disasembled I will take it to a guy I know who has had a motorcycle machine shop for about 30 years around here. He bored out my last rebuild and seems to be pretty knowledgeable about 2 strokes. I'll let him look at the parts and see if this thing is salvagable.

I really don't know what I am looking at as far as rust damage and I am afraid even with you guys expertise I may need somebody to at least take a look.

 

[GatorMike]

Re: crossflow v4 rust in the lower left cylinder?

I've got a bad feeling about this one. The lower left piston, the one that looked the worst when I first got it open actually came out the easiest, one tap with the mallet and she slid right out. However the bore does not look good to me I can feel the rust around one of the exhaust ports, everything else feels smooth. It took some tapping with a hammer to get the two top pistons out but the bores feel smothe. All the rings were intact and not much visible rust on them.

I really don't know what normal is supposed to look like so I am trying to discribe everything. The rod bearings although they had rusty oil on them cleaned up shinny. Right now I do have a hangup I am working on though, the lower right piston is still stuck and the crankshaft is not in a position where I can get a socket on the cap screws so I still don't have the crankshaft out. I'm going to try again in the morning.

 

[Dhadley]

Re: crossflow v4 rust in the lower left cylinder?

Normal would be no rust anywhere on the inside, no water anywhere on the inside. We're not too woried about rust on the cylinders, they can be bored. We're not woried about rust on the bearings, they will be replaced. We are worried about rust on the rods and crank. They are expensive to replace.

We're most worried about where the water came from that made the rust......

 

[GatorMike]

Re: crossflow v4 rust in the lower left cylinder?

Thanks, so far I have seen no rust on the rods & crankshaft. Like I said though I haven't got the crankshaft out yet. Once I get that last piston to move so I can get to the cap screws maybe I can tell a little more. Then I will clean up the block and start trying to figure out where the water came from.

 

[GatorMike]

Re: crossflow v4 rust in the lower left cylinder?

We're most worried about where the water came from that made the rust......

Ok I have an update. I never got that lower right piston to move so the piston & crankshaft are still in the crankcase. I did stop by the motorcycle shop that is going to bore it out for me and the machinist told me to bring it to him he will get it out. Yes I said motorcycle shop, this guy runs a one man motorcycle machine shop/fabrication/welding shop and came highly recomended. He does a lot of outboards and did my last one for me years ago. Anyway I am sure he will look the thing over for me and make any suggestions he has but I thought I would ask anyway. What do I look for in trying to determine how the water that caused the rust got into the crankcase?

Like I said earlier all 4 cylinders had some rust in them, the top two were more like surface rust that cleaned off with an oily rag once the pistons were out. The bottom left looked nasty and has some rusty areas that are still rough however strangly that piston was the only one that came out easily. The lower right piston is still stuck. The crankshaft and rods are still shiney at the smoothe areas but have a little surface rust on some of the other areas. I'll let the machine shop guy determine the damage since I'm sure he is a lot more experienced at these things than I am. Hopefully he can help determine where the water got in too but I thought I would ask here also.

Oh I thought I would add, most of the rust in that lower left cylinder that is rough to the touch starts at the exhaust ports and runs back into the cylinder. It is at the bottom of the cylinder and wider at the exhaust port then tapers down narower deeper into the cylinder.

 

[emdsapmgr]

Re: crossflow v4 rust in the lower left cylinder?

Any chance you have water in the fuel tank or oil tank? Have you taken a sample to check for it?

 

[GatorMike]

Re: crossflow v4 rust in the lower left cylinder?

Any chance you have water in the fuel tank or oil tank? Have you taken a sample to check for it?

I won't rule that out, however I seriously doubt it came from the tank. I have a fuel/water separator on the boat and the last time it was used, last April on vacation I ran a tank and a half of gas. One would think if there was any water in the tank I would have ran it out.