Inspecting Manifold

[merc 140 pontoon]

1974 Merc 140. Combined intake/exhaust manifold.<br /><br />The manifold is off. How can I check for cracks that might allow water (from the raw water exit passages) to leak into the intake ports?<br /><br />Is this strictly a visual process (with or without dye penetrant), or is there some pressurization method?<br /><br />I ran water through the water passages, and none came out of the exhaust ports, but the manifold was cold. My boat shows excessive steam from the exhaust, but only when the temp climbs above 190 degF, and I'm shutting down. (I'm troubleshooting an overheating problem.)<br /><br />Thanks.

 

[The Marine Doctor]

Re: Inspecting Manifold

Your local machine shop is your best bet.<br /><br />TMD

 

[cobra 3.0]

Re: Inspecting Manifold

You manifold may hac=ve been leaking at the gasket. It may not be cracked.

 

[rodbolt]

Re: Inspecting Manifold

hello<br /> 190 degrees is way to hot for this motor. check the seatater pump. replace it if it has not been done in the past 2 years. then check the circulating pump. then check the riser/manifold mating passages. some of the parts for this riser may be hard to find. and the riser is a choke point for the discharge water. if ya cannot get the water out the motor will get hot. good luck and let us know