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Blown head gasket?


Bryant fish

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Hi all ongoing saga with tohatsu mc40 has been running rough .steam coming out of exhaust relief idont know how to check  correct operation of that have removed  thermostat and replaced impeller .talking to mechanic he thinks maybe head gasket blown any thoughts  before  I take head off as gaskets $80 thanks

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Compression test should reveal head gasket, do not leave the thermostat out, did you replace the entire water pump kit, or just the impeller? Check the spark plugs, if water is getting into the head, they will be steamed cleaned.

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OK, let's go way back to the start, is the motor over heating? Does it run rough all the time? Have you checked the spark? Have you cleaned the carbs completely? You need to know the basics before jumping to other possibilities.

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3 hours ago, Bryant fish said:

Ha ha was actually easy expected seized bolts but no dramas

Did better than me... I snapped 2 stainless steel bolts in my Yamahaha water jacket cover.....

I sold the boat "as is" and the buyer had the skills to get them out!

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So being out of work tried to use gasket off a spare motor and save some coin guess what big improvement but still small amount of steam coming out.have ordered new gasket and will do it right this time i know I'm a dickhead☺

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YeahSo being out of work tried to use gasket off a spare motor and save some coin guess what big improvement but still small amount of steam coming out.have ordered new gasket and will do it right this time i know I'm a dickhead☺

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Ok so after a brain fart got new head gasket. There was some pitting on the head from saltwater so used head from old spare motor went to do that first time and tried to put thermostat housing on different from newer motor place I got gasket  had older thermostat  cover all good.went out today from parsley bay to target blue spots wind was terrible nothing like report crap fishing but motor run great I have a twin setup and motor I bought new never missed a beat other motor  was a bargain about 5 years ago so do expect some problems 

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