Hi I’m new here . Have a question

[Volkswagen503]

I’m hoping for an mercury 850 thunderbolt expert .

just changing my water pump and noticed a small hose right near the one large stud . What is it for ?
vent hose ?

please give me some info , thanks

 

[roscoe]

Is a pressure hose for a long obsolete speedometer.

 

[racerone]

A picture would confirm.------I would say your motor has a much newer lower unit.----Yes the newer units used a pitot hole in the gearcase and wee tubing for a speedometer.-----I believe I am going to spring for a GPS driven speedometer for my project boat.-----Just supply 12 volts to it.

 

[Volkswagen503]

Yes I figured out that it’s for a speedometer.
thanks .

now I have a real problem .

i haven’t had this boat and motor very long and I have only let it idle in neutral and seems just fine . And this is with in a water drum .
but yesterday I decided to put it in gear for a second and fling all the water out but it just stalled .

so it isles fine in neutral but stalls when put into gear .
iv searches a lot and sounds like a lot of people have this problem but I haven’t found what the actual cause could be .

thanks

 

[racerone]

Open the low speed mixture screws 1/8th turn at a time and test run.