Merc 5.0 won't start after freeze plug failure

2002 Merc 5.0 Port engine lost power and I looked at my temp gauge and it was at 200. stopped to check it out and noticed that a guiser was comming out of the top of the engine when I tried to restart it (there was never an over heating alarm). Found out a freeze plug on the top of the engine had a hole eaten through it. Now it won't start. Apparently salt water was spraying ALL OVER THE PLACE IN THE ENGINE COMPARTMENT, and water may have sprayed into the spark arestor and then into the engine. I dried out the engine, repalced plugs and wires and it still won't start. Also compresion test has 3 cylenders in th 80's the rest are OK. Any thoughts????

Re: Merc 5.0 won't start after freeze plug failure

and noticed that a guiser was comming out of the top of the engine

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Do you have a picture? There are no core plugs (mistakenly called freeze plugs at times) on the top of the engine?

Is it a geyser of water? Do you have spark?

If you get it started, your compression MAY come back.

Re: Merc 5.0 won't start after freeze plug failure

Also compresion test has 3 cylenders in th 80's the rest are OK. Any thoughts????

Click to expand...

Ayuh,.... Welcome Aboard,.... Yer way overdue for a new motor....

Re: Merc 5.0 won't start after freeze plug failure

Don S said:

Do you have a picture? There are no core plugs (mistakenly called freeze plugs at times) on the top of the engine?

Is it a geyser of water? Do you have spark?

If you get it started, your compression MAY come back.

Click to expand...

The spark is minimal when out of the engine, not like the spark on the good engine.

Re: Merc 5.0 won't start after freeze plug failure

The spark is minimal when out of the engine,

Click to expand...

What does that mean ?????????

What about my other questions?

Re: Merc 5.0 won't start after freeze plug failure

Don S said:

What does that mean ?????????

What about my other questions?

Click to expand...

Sory acutally we replaced the wires today and it had a good spark at all 8 cylinders. It stated and ran for 15 seconds then slowly died out.

I don't have a picture of the plug but it was a brass threaded plug on the top front port side of the engine.

We also tried swapping the ECM from the bad engine to the good engine. the good engine ran fine.

This is a 2002 290 sea ray amberjack with shut offs and keys in the control pannel down below in the cabin. When I first tried to start up the engine the next day, I heard a Beep alarm sound once when I turned on the switch for the bad engine in the control pannel. I have never heard that before????

Re: Merc 5.0 won't start after freeze plug failure

Help, we had a certified mechanic along with his computer come and take a look and it still won't start.
after the core plug failure.
1. switched ECM no start.
2. Switched coil and rotor no start.
3. volt readings at all the plugs good.
4. switched map sensor no start.
5. Checked fuel presures and gas all seem good.
6. fuel is avaiable at the injectors.
2 days ago after changing the wires, it did start normaly and ran for 15 seconds and slowly died. Has not started since. The emerc certified tech is contacting merc csuase he's stummped.

Any one with an idea??? It has spark it has fuel the only thing I can think of is that SALT water did get into the spark arestor, WHAT COULD THAT DO????

Re: Merc 5.0 won't start after freeze plug failure

eli whitney said:

Help, we had a certified mechanic along with his computer come and take a look and it still won't start.
after the core plug failure.
1. switched ECM no start.
2. Switched coil and rotor no start.
3. volt readings at all the plugs good.
4. switched map sensor no start.
5. Checked fuel presures and gas all seem good.
6. fuel is avaiable at the injectors.
2 days ago after changing the wires, it did start normaly and ran for 15 seconds and slowly died. Has not started since. The emerc certified tech is contacting merc csuase he's stummped.

Any one with an idea??? It has spark it has fuel the only thing I can think of is that SALT water did get into the spark arestor, WHAT COULD THAT DO????

Click to expand...

Also compresion test has 3 cylenders in th 80's the rest are OK.

Click to expand...

Ayuh,.... Fuel, Fire, Compression, 'n All the the right Time, makes our motors run....

Ya say it's got fuel, 'n fire... No mention of Timing, 'n yer lackin' Compression....