Diagnosis HELP...... Mercrusier 165 inline 6

[Michaelbluewolf]

Hello,
I have a 1970 Sea Ray SRV 190 with the Mercrusier 165 inline cylinder thats all stock. The problem is number #6 cylinder is taking on water. Removed all sparkplugs today and turned over the engine, There was a geyser of water from the rear cylinder #6. Now, I had just hooked up the water hose to the water feed hose at the front of the engine that goes to the water outlet/thermostat housing. Then performed the above operation. The engine was not run for 6 months prior to this.
I have 30 plus years as a Auto mechanic, but my inboard boat engine diagnostics are not that great, I am looking for some experienced help here. Please, accept my humble thanks to all who respond.
Mike
P.S.
I am thinking headgasket leak, but, like I said not sure about inboards. Could this be a manifold problem?????

 

[BonBini]

Hi Mike: Basic water flow would be, to the thermo stat housing, block to cylinder head via water pump (just like auto), out thermo stat to exhaust manifold (exclusive to marine).

With your water hose test, you may have let water enter #6 from cooling water exiting exhaust manifold. Try blocking off water to exhaust manifold and retest.

 

[Red Horse]

It is probable that your exhaust manifold is bad. They will rust out and allow water into the cylinder much like a blown head gasket.

I had a 165 HP six cylinder in a Glastron that was run in salt water for years. Good solid engine that ran well. Only thing other than routine maintainance was exhaust manifold, one starter and one altenator. That was from 1977 to 1994.