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Merc 40 hp wont start

M

mellfam8

New member
"Hi everyone my mercury 1980 4

"Hi everyone my mercury 1980 40 hp will not start!!! Problems that I've noticed recently while it was running are misty spray of water out of the top spark plug hole with spark plug installed. It will not idle at all ( just had the carb rebuilt one month ago ), the last 3 times out the motor ran bad rough idle and sputtering and not getting on plane. before it got this bad it ran fine once it got up to speed but now it wont start and IF it does motor wont stay running. Can someone please assist me? Thanks"
 
You need to find out why that

You need to find out why that water is coming from the plug hole. You may have a cracked head which would account for the rough running. Have you done a compression check?
 
Compression check 75 top 135 b

Compression check 75 top 135 bottom cylinder. Any more advice before I take it to the shop? Thanks
 
"save the shop fee, she's

"save the shop fee, she's gone. You can remove the waterjacket cover (spark plug cover) and find the crack yourself."
 
Is it guaranted done or could

Is it guaranted done or could a bad water jacket cover make the compression low and the head not be cracked?
 
"How can water be coming out o

"How can water be coming out of the spark plug hole with the plug in? unless the head is cracked where the plug go in , With it running????????????The block would have to have a crack in it ,lower down letting water get in the cylinder. SOOOOO you could not see it, The water jacket has nothing to do with the compression, or the head , It has no HEAD This is a 2 part block, head and cylinder are the same piece"
 
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