Oil Injection line question

[Z-man228]

I recently went into the garage and found 2 stroke oil on the floor under my 1988 Yamaha EXTG starboard motor. From what I can see, it appears to be leaking from a line while running, gathering in the buckets, and then running down the midsection and foot onto the floor while parked. I looked up the schematic and Yamaha has 2 different lines coming from the pump joined In the center with a "connector". My question would be
1) is the connector necessary? What function does it provide?
2) could I get some petroleum safe rubber tube and route to each carb from the oil pump in a single piece and eliminate the connection.
3) any recommendations on the type of tubing to use if I don't order the OEM Stuff

[boscoe99]

Need a complete model identity.

Better still, a link to a parts catalog reference that depicts the line/hose in question.

[Z-man228]

it is a 1988 Yamaha 150 extg oil Lines running from the oil pump to the Carbs
oil.pdf

[boscoe99]

I recently went into the garage and found 2 stroke oil on the floor under my 1988 Yamaha EXTG starboard motor. From what I can see, it appears to be leaking from a line while running, gathering in the buckets, and then running down the midsection and foot onto the floor while parked. I looked up the schematic and Yamaha has 2 different lines coming from the pump joined In the center with a "connector". My question would be
1) is the connector necessary? Only to connect two hoses together it would appear. What function does it provide? To join two shorter lengths of hose into one longer length of hose.
2) could I get some petroleum safe rubber tube and route to each carb from the oil pump in a single piece and eliminate the connection. Yes, don't see why not. If the connector is really just a connector.
3) any recommendations on the type of tubing to use if I don't order the OEM Stuff Tygon or other oil resistance tubing of the same ID.

On the original version of your motor the connectors are stated as being a "joint". Which is typically Yamaha's name for a hose barb.

Now if your model motor has the upgraded oil pump then the connectors will no longer be connectors. They will have been replaced with check valves.

In the original motor check valves were in the oil pump. The oil pump was discontinued. The replacement pump does not have internal check valves. So check valves were installed in the oil lines.

[Z-man228]

So they do serve a purpose if they are check valves. I don't know if the pump has been upgraded or not. I have owned these since 2003 and have never had an issue with the Oil injection system until now. All the lines are rock hard so it looks like time to replace. Any way to tell if the pump has the check valves in it?

[boscoe99]

So they do serve a purpose if they are check valves. Yes. They allow for the movement of oil in one direction only. I don't know if the pump has been upgraded or not. I have owned these since 2003 and have never had an issue with the Oil injection system until now. All the lines are rock hard so it looks like time to replace. Any way to tell if the pump has the check valves in it?

Look at the connectors. A check valve might have a directional arrow on it whereas a "joint" should not.

[Z-man228]

Cool thanks for your help and Advice will see what I can find out after work tonight

[rodbolt17]

its even easier than that.
the old kien pumps the outlet nipples point up.
the mikuni pump,uses check valves, the nipples are about horizontal.

[Z-man228]

Mine point up. Will start to disassemble and see what is cracked/broken. Are the check valves still available if needed?

[boscoe99]

Mine point up. Will start to disassemble and see what is cracked/broken. Are the check valves still available if needed?

If you have the old style pump you don't need separate check valves. They are integral with the pump.

Only the updated pump uses external check valves.

But yes, the check valves are available. So are the joints aka hose barbs.

6R3-13183-00-00 YAMAHA VALVE, CHECK

6E5-13132-00-00 YAMAHA JOINT

[99yam40]

Could it be that a check valve is not doing its thing properly allowing the oil to flow out of that line more that it should be even if it is cracked or not.
Just a thought

[boscoe99]

Could it be that a check valve is not doing its thing properly allowing the oil to flow out of that line more that it should be even if it is cracked or not.
Just a thought

Maybe the OP needs to thoroughly clean the motor and then run it to find out where the oil is coming from. Might be helpful to add some dye to the oil.

As you probably know a little oil can go a long way and the leak will seem much worse than it really is. Hopefully just a new clamp might be needed.

What is not known is if he keeps the motor tilted up. The sensor seal in the oil tank is known to leak when the seal gets oil and loses a bit of grip.

[Z-man228]

I should have been more concise. Motors are in down position In the garage. it doesn't leak while just sitting there i.e leaking until oil tank goes dry, it only does it after being run which tells me something is leaking while it is under pressure. Hard to tell where it is coming from when the motor is running as 1/2 of the hoses go behind the carbs and exit on opposite side of motor from the oil pump.

One thing I did discover is all of the lines are hard as rock, time to replace them anyway. I just wanted to really understand the system before I just dove into it.

[Jerry Bailey]

Just to follow-up. No one really commented on oil lines being hard except to say use tygon or oil resistant line. When should they be replaced, hard/soft? Is vinyl not oil resistant? Where would find this tygon?

[boscoe99]

Here is some. Not sure if it is the correct size for a Yamaha outboard motor or not.

NATURAL CLEAR OIL INJECTION TUBING 5/32 INCH from Aircraft Spruce

POLYURETHANE TUBING from Aircraft Spruce