50 Yama front p hole tube?

[Big-G]

My 2005 50 hp 2 stroke Yamaha (recently purchased) has a small tube extending from the front of the engine under the cowling to the inside edge of the transom. The tube has been crimped with nylon/plastic ties but the rubber on the tube has dry rotted and leaks what appears to be sea water into the boat. I can cut away the waste and cap the tube with a rubber nipple and clamp but I am reluctant to do so because the flow of water must have a purpose and I don't know what it is. Records show $300.00 plus maintenance on motor in March by Yama dealer and the ticket says nothing of the tube so I'm assuming clamping the tube would not cause problem. Need some feedback from you knowledgeable folks. What is the purpose of the tube and is it safe to cap it?

[phatdaddy]

not sure of that model, is it a flush tube that had a hose adaptor on it to flush without running motor

[Big-G]

Originally Posted by phatdaddy

not sure of that model, is it a flush tube that had a hose adaptor on it to flush without running motor

Found schematic of motor that shows original configuration (tube without crimp) and it does show a plug at the open end of the tube. This plug looks a lot like fuel connections on some of my small engine devices. The plug is tapered and has ridges so that a small tube could be pushed over the plug and remain stable. If it is there for flushing the engine it would make sense, however, the input tubing that attaches to this plug would have to be small.

G

[smokeonthewater]

Speedometer pressure tube.

[phatdaddy]

previous owner might have had a pressure gauge on his console.

when does it pee water?

[Big-G]

Originally Posted by phatdaddy

previous owner might have had a pressure gauge on his console.

when does it pee water?

Pees water when under way, not at idle. Pressure gauge sounds right.

Thanks a bunch. Will cap it off and take her out tomorrow. You guys are great!

G

[smokeonthewater]

Not pressure gauge, speedometer..... The key is that it only produces water while underway.
There is a pickup on the lower unit of the motor and the faster you go the more water pressure there is so the higher the speedo would read...
If it was for a water pressure gauge it would discharge water any time the engine was running and revving the engine in neutral would increase to pressure/flow.

[phatdaddy]

smoke, if i understand him right, tube is coming off the block under cowling,
i thought the speedo comes off the lower unit.

if he's got a schematic, should be able to follow to source or if it pees on a hose, part of cooling system, if not, speedo.

either way, not that hard to trace

[Big-G]

The schematic shows the tube coming from under the cowling and clamped down with a clip attached to a grease fitting that may be for the steering rod encasement. Cannot follow tube (using schematic) beyond the cowling.

I do remember a similar tube my older motor - 1985 Mariner. The southern end threaded through the lower unit and could have been there to provide water pressure to the Northern end of the tube. I didn't pursue it further because the motor always performed to expectations.

G

[phatdaddy]

ok, if it's off the foot, it's speedo

good call smoke