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Mercruiser 120 blowing exhast out the cooling lines

V

vroomZOOM

Regular Contributor
Hello

I have a buddy that bought my boat with a 2.5 mercruiser 1987 and now when he tries to start it, he says it just backfires out the carb and there is exhaust coming out the cooling lines. When I winterized the engine I took out the drain in the bottom of the block, and the drain in the bottom of the manifold with the nose of the boat slightly raised. I then disconnected the hose at the top of the thermostat and put a little antifreeze to flush out the water, just in case. What is going on with this troublesome engine again?:mad::mad::mad:
 
That unique motor has its intake and exhaust manifold combined in one unit. It's possible a crack or rotted hole in the exhaust could send exhaust out the carb.

Jeff
 
he says it just backfires out the carb and there is exhaust coming out the cooling lines.
Click to expand...

Ayuh,...... Back-fires through the carb is a symptom of a lean condition,......

Aren't the coolin' lines full of Water,..??..??
 
ROFLMAO LOL LOL LOL.just realized what is going on. its not a head gasket or anything. this was buddy's first boat so he must have ran it on the trailer to see if the motor was working, and he ran it without ears, so now the pump is shot DUH... now when he put it in the water he tried to find out if there was any water coming out the cooling lines. Ya, you got it, lol, there is no water in the cooling lines, and the exhaust pressure just goes right back through the riser and out the cooling lines. Heh heh that was funny,:D lolz, though I freaked at first though. thanks for the help. lesson learned for him - try just not running it without ears, and then you wont have to buy an unneeded head gasket.:D :D
 
lean condition because the boat sat for a while and the carb must have dried out, and needed some cranking to get er going.
 
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