Logo
FULL SITE MENU

Just got a used boat, possible cracked block, advice? Thanks!

C

COchoa

New member
Hi guys. I'm new on here. Any help would be appreciated.

I just pick up a 1988 Sunbird Eurosport. The engine is a 4.3 L 260 CID V6 OMC Cobra. The boat was basically a gift. I was told the engine leaks water. The previous owner doesn't know where the leak is coming from. He just assumed it was a cracked block. (This is why it was basically a gift) The motor apparently runs but I haven't tried to start it yet because I cant check the oil. The dipstick hole near the starter is plugged and I don't have any information on the last oil service. This is my first I/O boat. Previously I owned an outboard. This leads me to my questions...

1. How do I remove the plug in the oil dipstick hole to check the oil? I want to verify that there is no water in the oil and that there is in fact oil to begin with.

2. Are there common issues or locations for a water leak or cracked block? IE: Freeze plugs, gaskets, water jackets and so on...

3. Do you have any suggestions or advice to go about checking the motor over? I don't know much about the motor or service records.

Any advice would be a great help.

Thank you in advance,

Chris,
 
OMC didn't use the GM block dipstick hole. OMC installed a pipe that runs to an elbow on the oil pan drain plug hole. In the pipe was the dipstick, and the pipe is also threaded for attaching a pump to change oil.
see lower right corner of this pic:
154151.jpg
 
COchoa said:
2. Are there common issues or locations for a water leak or cracked block? IE: Freeze plugs, gaskets, water jackets and so on...
3. Do you have any suggestions or advice to go about checking the motor over? I don't know much about the motor or service records.
Click to expand...

chevy v6's crack in the galley area of the block under the intake in where the lifters reside.
like this:
miscapril2007012.jpg


to check for cracked block, remove the hoses running from the tstat housing down to the exh. manifolds and block them off with bolts (or wood dowel etc) and clamps at red X's
then remove water supply hose and introduce regulated air pressure of 5 to 10 psi at green arrow
if you hear hissing, you have cracks. If removing the valve cover or even just the oil fill cap makes it louder, the block is probably cracked by the lifters.
searay.jpg
 
I may have worded that wrong. This attached picture is the engine I have. On this picture from the internet, there is a dipstick on the bottom right. However on my engine, the hole OMC 4.3.jpghas a metal plug in it.
 
I don't know what that cut off tube is in your pic, but I doubt it was the dipstick.-looks like a chopped fuel line or something. maybe it's the dipstick, but it doesn't go to the block if so - it goes to the bottom of the oil pan.
ALL OMC 4.3's have the GM dipstick tube hole in the block plugged off because they use the system I described above. do not try to unplug it. There will be a welch plug that would have to be drilled which would contaminate the engine crankcase.
 
First, There is nothing free about a "free boat". The engine in your picture is definitely not the original. By the time you are done repairing (replacing) this engine you can purchase a running boat that is not obsolete.
 
Welcome aboard !

So the pic you put up is not your engine correct ?

Ok run your hand over the drain plug on the pan feel it ? Is it solid or is there a hole in it you will feel it. Maybe sharp pieces of metal where the dipstick pipe used to be ?

Mine was half cracked off. I finally just broke it off removed the plug soldered the hole closed, and re-installed it. I then carefully drilled my welsh plug using a vacuum i don;t think one little piece of metal made it's way into the pan.

I went down to the local junk yard and they gave me the tube and dipstick. I think i gave the guy a beer.

Sounds like something you can do ?
 
Back
Top