Mercury 300xs Oil Injection System Question

[Pachanga_rick]

Ok, I'm so used to pre-mixxing my oil this system has me 2nd guessing myself.. question is

I primed the system as the manual says - Turn on the key, pump throttle forward 3 times and allow system to prime.

No problem, sucker drank down almost 1/2 the oil tank on the engine..and called it a night as the bugs were biting.

This morning I noticed this oil line running into the oil injection pump looks clean and dry, like not oil was pumped to the injector pump.

Should this line show oil? (Clear line with white breading)

[Euroski]

I will check mine later this eve. It's been setting since Sunday

[Euroski]

Mine still has oil in hose. I would re-run the prime again and then check.

[mjw930]

The prime will not push oil from the tank to the motor reservoir, it takes pressure from the motor when it's running to pressurize the remote tank and push oil back into the motor tank. The procedure to refill the motor tank is to crack the reservoir cap when you start the motor and carefully watch as the reservoir fills up then close the cap just as the reservoir fills up, this purges the air from the system. It will fill quickly once pressure builds so be quick to close the cap or you will have a bit of an oil spill to clean up.

[Euroski]

True, but it looks like from the picture it's the hose between the pump and engine mounted oil tank. So... that hose shouldn't be empty unless the engine mounted tank got too low.

The prime will not push oil from the tank to the motor reservoir, it takes pressure from the motor when it's running to pressurize the remote tank and push oil back into the motor tank. The procedure to refill the motor tank is to crack the reservoir cap when you start the motor and carefully watch as the reservoir fills up then close the cap just as the reservoir fills up, this purges the air from the system. It will fill quickly once pressure builds so be quick to close the cap or you will have a bit of an oil spill to clean up.

[mjw930]

True, but it looks like from the picture it's the hose between the pump and engine mounted oil tank. So... that hose shouldn't be empty unless the engine mounted tank got too low.

The problem is oil isn't pulled into the reservoir, it's pushed in so without the motor running there's probably not enough residual pressure in the tank to replace the oil pulled in to prime the system.

[Pachanga_rick]

This is almost comical so bare with me..

I primed the oil system again (4 times total now) and more than 1/2 the oil in engine mounted tank was sucked through, so the motor had oil.. yet the hose still looked clear. So I removed the hose entering the pump and... ready for this, Mercury used a gold'ish color oil in the system for break in.. lol. I was expecting blue oil.

I refilled the engine oil tank with Hi-Perf (blue) oil and fired the engine.. I smoked the yard heavily and you could slowly see the oil in the line change color.

So long story short, I was worried about nothing...

[Turborr]

Better to be worried about nothing than not to be worried about anything!

[ghost28]

Opti oil is gold not blue...that line is full....be careful with priming the oil pump more than once as i have seen guys who thing if once is good 5 times is better and they hydrolock a cyl on oil.....

[mjw930]

Actually, the high performance, aka Mercury Racing oil is red, not sure what the blue stuff is.

[Pachanga_rick]

Actually, the high performance, aka Mercury Racing oil is red, not sure what the blue stuff is.

They offer a red oil and blue, I was told both are acceptable in the 300xs. I'm not sure of the difference, I think the "red" is a new blend. I'll look it up today.

[vnemous]

I'm not sure about the XS but going in and out of gear with engine off but key on a bunch of times may put you back in break in. Ghost is correct DFI oil is gold.

[mjw930]

They offer a red oil and blue, I was told both are acceptable in the 300xs. I'm not sure of the difference, I think the "red" is a new blend. I'll look it up today.

They don't make it easy, they specify one oil in their brochure and another in the owners manual.

Here is an official response from Mercury regarding the recommended oil for the 300XS, "The customer should be running the Mercury Racing 2 Stroke Oil, which is part # 8M0078011. The current labels are the blue foil labels. The black and yellow label is the same product but it is just a bit older than the blue foil label.".

This is the old label:


This is the new label: (sorry for the low resolution)



Both of these are red.

Sorry, didn't mean to turn this into an "oil" thread.......

[vnemous]

Very confusing mercury is. They have a service bulletin saying to only use DFI in the optimax contradicting there owners manual. Go figure.

[Euroski]

And this is from my 300xs Mercury factory repair manual...! Got to wonder why there are so many topics on oil!