86' Mercury 150 xr2 V6 pre mixed fuel blowing out of positive pressure ports of crankcase

[ratchet2]

I have pre mixed fuel blowing out of positive pressure ports of the crankcase on a 1986 Mercury 150 V6 XR2. I noticed the fuel spraying out of the oil injection pressure line port on the motor to the 3 gallon oil reserve tank after the oil reservoir was slow to fill, also found premix in the reed bleed line small tubings. I immediately suspected the fuel pump diaphragm had ruptured, but it checked okay, plus it's pre mixed fuel, not raw gas. I assume this is why the motor smokes excessively at idle, and sluggish at half-speed? Not really sure if this could be caused by a stuck float on another carburetor problem?

 

[Faztbullet]

Post a pic of these positive pressure ports. Is the oiler still in operation?

 

[racerone]

Agreed----pictures of these ports.

 

[ratchet2]

It's the port (looks like a PCV) that puts the pressure to the oiler large tank in rear storage compartment, also pressures the oil up to the small reservoir tank on the motor, . Yes, the oiler is still functioning. After reading up on the reed bleed lines, that is their function to return unused fuel to the cylinders to be burnt, so maybe what I'm seeing is normal? Just seems odd to have pre-mix pressuring into the unused 2 stroke oil?

 

[ratchet2]

Pressure port circled in red.

 

[racerone]

If you remove the hose from that port you will see leakage with motor running.----With the hose on there is only flow until the tank gets pressure.-----Pressure bleeds off when motor is not running.-----Repair any leaks found on fittings.

 

[ratchet2]

If you remove the hose from that port you will see leakage with motor running.----With the hose on there is only flow until the tank gets pressure.-----Pressure bleeds off when motor is not running.-----Repair any leaks found on fittings.

Wow! Thanks, it really looked like a serious problem at first to me. 2 stroke motors are "crude" tough sweethearts.

 

[ratchet2]

Any thoughts on the super smoker issue? from what I read the oil injector pump should regulate a lower oil mix at 100 to 1 at idle. The carbs were cleaned, tested and .064 jet added to the main, idle jet .056. The oil injector pump was tested as well, and correct oil amount was accumulated. All testing and work was done by previous owner, that I trust. I tested compression yesterday, all 6 at 125 psi.

 

[Faztbullet]

Smokes after it sets between use or all the time?

 

[ratchet2]

Smokes after it sets between use or all the time?

Smokes after it sets between use or all the time?

I’d have to say always, hard to tell when on plane. I’ve owned the boat for a month now, my old boat I ran for 30 years, 1974 85 hp Mercury, that all I can compare it to. Had it on the water hose “muffs” today, it reminded me of flushing a auto intake with seafoam. Glad the neighbors are some distant away.

 

[Faztbullet]

Sound like you have some stuck/dirty recirc valves or pressure fitting is not bleeding off. Had a lot of problems with em in the late 80's.

 

[ratchet2]

Sound like you have some stuck/dirty recirc valves or pressure fitting is not bleeding off. Had a lot of problems with em in the late 80's.

Thanks! I’ll have to find my old fuel pressure gauge kit and test them out. I verified yesterday that the bleed tubes are routed correctly.

 

[merc850]

"and .064 jet added to the main, idle jet .056" Why was this done? Just for my education.

 

[ratchet2]

I’m not sure, I bought the boat a month ago. Found some maintenance paperwork where the previous owner clean and adjusted carbs back in March, and changed them out then. Not sure what the ”original“ jets were, but I assuming it was for a improvement reason??

 

[merc850]

Is your altitude above or below sea level? that's normally the reason for changing.

 

[ratchet2]

800' above sea level. I may have "misread" the maintenance log, it read "jets now", I figured that meant he changed them, maybe he logged what was in the carbs for a reference later on?? I have a true Mercury manual being delivered soon, I'm curious to see what the jet sizings are.

 

[merc850]

OK

 

[Faztbullet]

You don't need gauges to test recirc valves or pressure fitting. Pull hose off recirc fitting while running, if fuel emitted from it is not a fine mist it needs either attempted cleaning or replaced. The pressure fitting for oil tank is simple, use it a day as normal then check tank the next morning ,if it has pressure when you remove cap it is bad.

 

[ratchet2]

Great info on how to test the recirc fitting and oil line pressure valves. Are the recirc fittings at the spark cylinder small check valves too, like the ones on the reed block?

 

[Faztbullet]

No they are just fittings...