4.3 wont start after overheating a little

[sebas54]

Hi, I am new to this forum. I really need some help. I have a 1987 4.3l merc engine. Today I was out and noticed the thermostat rising to about180-200 (usually stays around 130). I turned the engine off and called sea tow (the engine did not stall). While waiting I started it back up just to see. Well the temp kept going up, so I shut it down. Got back to the dock and tried her again and no start. SHE won’t even start Now!! Checked the oil and it looks fine, not milky or creamy. I tried a couple more times to star her and no go. The engine barely revs up when trying to start and sort of bangs or back fires. I really need to get this fixed. I love to fish and the fall is upon us. Please help.

 

[JustJason]

Re: 4.3 wont start after overheating a little

so many possibilities here..... best bet to take it to a shop....
if your looking to save a few bucks... you could always pay them for the diagnostics then do the actual work yourself..

 

[Haut Medoc]

Re: 4.3 wont start after overheating a little

Hi, I am new to this forum. I really need some help. I have a 1987 4.3l merc engine. Today I was out and noticed the thermostat rising to about180-200 (usually stays around 130). I turned the engine off and called sea tow (the engine did not stall). While waiting I started it back up just to see. Well the temp kept going up, so I shut it down. Got back to the dock and tried her again and no start. SHE won’t even start Now!! Checked the oil and it looks fine, not milky or creamy. I tried a couple more times to star her and no go. The engine barely revs up when trying to start and sort of bangs or back fires. I really need to get this fixed. I love to fish and the fall is upon us. Please help.

Pull the sparkplugs & look for signs of water intrusion.....
If you find water on only one side, I would suspect the riser dump is restricted from scale & forced the riser/man gasket to fail..........
How old are the riser/mans & how old is the raw water impeller?....
The first thing I would do is pull the plugs & check for water, right now, don't wait to take it to a mechanic or it will be too late if there is water present...
In salt water you have hours, not days..........
If you have a bad riser/man it will take some time for water to seep past the rings into the oil.......

 

[sebas54]

Re: 4.3 wont start after overheating a little

Hi, Thanks for the reply's. I think that the manifold and riseres are pretty new and in good shape. I coudn't remove the spark plugs but i stuck my finger in the oil fill cap and indeed there was signs of water. Cream. So now what. Can this be fixed inexpensively? What exactly is wrong? Thank again to this forum and everyone on it.

 

[180shabah]

Re: 4.3 wont start after overheating a little

Can this be fixed inexpensively?

Not if you wait too long to get the motor dried out. Like I said in your other thread(about the same problem) take apart whatever you have to to got that water out of there. You can get dirty now, or write a check for 5-6k later when you replace the engine.

 

[180shabah]

Re: 4.3 wont start after overheating a little

...What exactly is wrong?

Don't know, but a little bit of dirty work will reveal all.

It overheated, you shut it down, now it has water in the upper portion of the head and possibly in a cylinder or two.

Perhaps you will get lucky and it will just be a blown head gasket. It could also be head or block damage. Cracked head being the most likely if there is evidence of water through the cap, but not in the crankcase.

 

[Bondo]

Re: 4.3 wont start after overheating a little

Like I said in your other thread(about the same problem)

Ayuh,.............. Like WOW Man.............

I thought I was losing what little Mind I have left,........

'cause I Know I Just posted on this thread,......................

Thankfully,......... I was Right,....... or is that Wrong.....

 

[sebas54]

Re: 4.3 wont start after overheating a little

Thanks for all the info. Just got back from disassembling the risers/manifold and pulling the plugs. Well it looks like there was some water on the spark plug itself but once removed no water came out. All three plugs on one side seemed to have some moister. The fill cap had no water as I stated earlier. It was just condensation on the top of the cover. The dipstick oil is still black. I started removing the screws under the spark plugs (there were about ten) and they were filled with water. I removed the water and there were no signs of oil just water. ??? I stuck a hose in the spark plug hole and started pumping and nothing came out. I don't know what to do please help. I am sorry asking it two ways. Thank you again.

 

[akwalker]

Re: 4.3 wont start after overheating a little

I stuck a hose in the spark plug hole and started pumping and nothing came out. I don't know what to do please help. I am sorry asking it two ways. Thank you again.


,,,,,sir,,,,, please put the screwdriver down, and step away from the boat,,,,

 

[Haut Medoc]

Re: 4.3 wont start after overheating a little

You need to make sure that no water is being supplied to the engine....
If necessary, pull the drive so as to not damage the impeller or supply water to the muffs & diconnect the inbound water supply & divert it.....
Drain the block....
Put the plugs back in.....
Put the man/risers back on.....
Change the oil & filter....
Start the engine & run for no more than 30 seconds......
You can do this more than once, if you let it cool between starts.....
If the engine will start & run easily.....
Replace the riser /man on the 'wet' side.....
& get ready for the other side to fail if you don't replace it too....
Just how old are they anyway?.....​

 

[sebas54]

Re: 4.3 wont start after overheating a little

I think that the manifolds and risers are about 1 to 2 years old. When I removed them they looked good. The gasket looked good also.

 

[sebas54]

Re: 4.3 wont start after overheating a little

Haut Medoc you told me that I shoud drain the block. How do I do this? Thanks

 

[Gary H NC]

Re: 4.3 wont start after overheating a little

To drain the water from the block on a 4.3 there should be a brass drain on each side of the block below the manifolds and head,just a few inches above the lip of the oil pan..It will be a brass plug or a pitot type drain that unscrews.Should also be a drain plug on each exhaust manifold.