1991 mercury sounding rough? fixes?

[1975oday22]

fresh gas, rough sounding ,shaking, any thoughts? ideas? also why is there water coming out the front of the engine. towards the tilt?

 

[dingbat]

fresh gas, rough sounding ,shaking, any thoughts? ideas? also why is there water coming out the front of the engine. towards the tilt?

Not hearing or seeing anything out of the norm for an outboard of that era.

The water is a different story.
Don't know that particular motor, but I would check to make sure water tube from pump isn't rotten out and or the rubber grommet is missing or damaged if it has one

 

[1975oday22]

Not hearing or seeing anything out of the norm for an outboard of that era.

The water is a different story.
Don't know that particular motor, but I would check to make sure water tube from pump isn't rotten out and or the rubber grommet is missing or damaged if it has one

at least i know now that the engine is fine. but that center hole where the water is flowing out of makes me a lil nervous. maybe missing a plug there? i dont know. i will check manual and see if that is something. ill also look online. but hardly ever do i find anything on 91

 

[1975oday22]

here is the hole where the water is flowing from when engine is running. not sure if its a threaded hole or not?

 

[1975oday22]

nothing at all in manual about this hole and ive spent awhile looking for it on line and nothing.

 

[dingbat]

at least i know now that the engine is fine. but that center hole where the water is flowing out of makes me a lil nervous. maybe missing a plug there? i dont know. i will check manual and see if that is something. ill also look online. but hardly ever do i find anything on 91

The only portion of the leg of the motor that is sealed is the gearbox. Everything else is open to atmosphere to facilitate drainage as evidenced by the hole the water is coming from

The only way to get pressurized water in that location is a compromised water tube or a leaking exhaust chamber. You need to drop the lower unit to see what is going on

 

[1975oday22]

what would i be looking for in terms of water flowing in this location? i hate not being able to find anything at all on my engine. everything else but 1991 merc 4 cyl.

 

[dingbat]

what would i be looking for in terms of water flowing in this location? i hate not being able to find anything at all on my engine. everything else but 1991 merc 4 cyl.

The only place you have pressurized water in this location is the water tube (pipe) running between the water pump in the lower unit and the power head.

Typically use a rubber seal to seal the connection. If you haven't changed the water pump assembly, it's time now

 

[QBhoy]

Sounds ok ti me. She’s also a 2+2 machine..which adds it’s own unique oddity and low rpm behaviour

 

[1975oday22]

Sounds ok ti me. She’s also a 2+2 machine..which adds it’s own unique oddity and low rpm behaviour

heres a better shot of the hole where the water is coming out of as well as a steady stream out the tell tale and the prop. im not exactly sure but i cant see how water would be getting up in there. ? and out for that matter.

 

[jimmbo]

That is a Drain for the Midsection, which fills with water after it is done cooling the Engine, and being that the midsection is about 20 inches tall, it develops its own head of Pressure at the Drains.

For running on 2 of the 4 Cylinders, it sounds pretty good, and very smooth.

 

[1975oday22]

That is a Drain for the Midsection, which fills with water after it is done cooling the Engine, and being that the midsection is about 20 inches tall, it develops its own head of Pressure at the Drains.

For running on 2 of the 4 Cylinders, it sounds pretty good, and very smooth.

thank you. now i can be rest assured that there is nothing wrong with my engine . now just to fix the tilt motor. lol

 

[havoc_squad]

fresh gas, rough sounding ,shaking, any thoughts? ideas? also why is there water coming out the front of the engine. towards the tilt?

That is what most 2 stroke carb'd outboards sound like under low idle out of the water (no backpressure/load).

The real test is how it sounds in the water and in gear. If it falls flat and stalls out or varies RPM wildly under low idle under load, then you need to do some investigation (compression test, spark test, fuel test, etc.)

 

[flyingscott]

Yup that motor sounds perfectly fine