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What is THIS??

Grumpy Bear

Grumpy Bear

Regular Contributor
1975 Mercury 500 50hp. See attached pics. A tiny little hose connected from the lower to upper powerhead broke (one pic shows where it broke, the other where it is connected on the lower end). With the motor running, it will only idle at full choke and fuel is spraying from the broken hose. What is it and how do I get that tiny brass tube that connects the hose to the powerhead outta there? Pull it or does it screw out??

Thanks!

photo1.jpgphoto2.jpg
 
kimcrwbr1 said:
http://www.marineengine.com/parts/m...639-usa/cylinder-block-and-crankcase-assembly
It is called a bleed hose and fittings the check valve is in the upper fitting. You should be able to just pull the chunk of hose off of the upper and lower fittings and put a new hose on part #s 24-26-27
http://www.marineengine.com/parts/m...639-usa/cylinder-block-and-crankcase-assembly
Click to expand...

THANK YOU! Only one caveat: The brass tubing for where the hose connects at the top broke. Does the top fitting unscrew out of the powerhead? Please don't tell me I have to get into the powerhead to replace that!
 
kimcrwbr1 said:
http://www.marineengine.com/parts/m...639-usa/cylinder-block-and-crankcase-assembly
It is called a bleed hose and fittings the check valve is in the upper fitting. You should be able to just pull the chunk of hose off of the upper and lower fittings and put a new hose on part #s 24-26-27
http://www.marineengine.com/parts/m...639-usa/cylinder-block-and-crankcase-assembly
Click to expand...

Oddly enough, the upper check valve on MY motor is *TINY* compared to those in the schematic. Motor serial # starts with 407. I have to replace it since the nozzle off of the check valve actually broke off. But I can't get a tool on the tiny nut on the top check valve to get it off. See the pic with my finger next to the check valve. The models surrounding this motor had much larger check valves. Gah!! How do I replace this? nut.jpg
 
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kimcrwbr1 said:
How long have you had the motor? How did it get broke? It should be a 7/16 brass fitting is it possible it just got broke off at the threads?
Click to expand...

Just got it a few weeks ago. This break is new. The nut/hex is still visible (as seen from the pic) despite the break-off of the stem. I will check the 7/16 but it seems way smaller than that.
 
If that don't work,there's a hole there already so use an easy out,heat the bejeasus out of it and turn it ccw,gently or the easy out may break
 
haventaclue said:
If that don't work,there's a hole there already so use an easy out,heat the bejeasus out of it and turn it ccw,gently or the easy out may break
Click to expand...

How would I heat it without the risk of blowing up (gas and oil all around it)? I will try again to find a hex bolt the right size and pop it loose that way. So, just out of curiosity, would this bleed hose loose, would that be the cause of the motor losing power or chugging out and dying when I take the choke off?
 
This hose must be replaced ! It returns the oil that has gone to bottom of the crankcase to the top bearing / cylinder for re-use.
 
I am well aware of how your motor works !----- this hose returns oil to the top for re-use !!!-------I own many of these motors and have worked on them since 1968 as well.
 
racerone said:
I am well aware of how your motor works !----- this hose returns oil to the top for re-use !!!-------I own many of these motors and have worked on them since 1968 as well.
Click to expand...

I'm sorry. I wasn't meaning to suggest you didn't know what you're talking about. Not at all! I appreciate your help. I was asking more for clarification. When you say it returns oil to the top of the crankcase, are you talking about the gas oil mix?
 
You need to understand the finer points of how a 2 stroke works.----------Oil from the mix works it's way to the bottom of the crankcase.-----it is then recycled to the top cylinder.
 
kimcrwbr1 said:
Be sure and use a six sided socket whatever size it is or you may need to drill it out! that will require splitting the crankcase.
Click to expand...

I assume you're saying that drilling would possibly put metal shavings in the crankcase which would not be good. The check valve is facing downward. If I drilled carefully and slowly, do you think I could drill it out without risking those shavings getting in there?
 
Someone shared with me that this upper connector is not a check valve but just a flow-through brass connector. Can anyone verify this? Would it really make much difference if it wasn't a check valve as long as the bottom connector was?
 
The hose returns oil to the top of the motor.------The hose usually has one check valve and it is the bottom fitting !
 
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