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Hi folks.
I’ve heard that my problem is quite common with this engine year (2005), especially on those with newer powerheads (2017).
Any speed under 5000rpms and the engine runs fine.
But creeping over 5000-5200 and I’ll start seeing the telltale exhaust smoke. I noticed this during the break-in procedure, which limited my WOT use, but I’ve been able to run it just under 5000 rpms enough that it doesn’t seem to be “making oil” from improper ring break-in (and the dipstick has never "Blown out"). But I’d still like to be able to open to WOT- just to make sure everything’s seated properly.
Currently at 300 hours on the new block.
Here's the common problem-
Oil is coming from the breather hose on the port head cover- then back into the intake manifolds where it gets sucked into the cylinders with each intake stroke. Excess engine oil is evident inside the manifold, plus in the breather hose and in small pools in front of the intake chambers where manifolds mount to heads.
But here’s the mystery-
The previous owner had apparently fixed this issue by installing the updated “T” connection on the breather pipe, allowing excess oil to drain back to the pan.
Before the rebuild, I never saw this smoke at high speeds, which leads me to believe something was reassembled incorrectly. I've made sure the oil level is not overfilled for multiple seasons now, so confident that too much oil is not the cause. The exhaust was also inspected and was in good shape (previous owner had replaced). Ring free and E-0 fuel have been used nearly exclusively since rebuild.
I know about the "anti-purge" kit that Yamaha made for these engines, but don't think adding a 3rd hose from to reroute oil to the filler cap is the solution (since I already have the added T connection to drain excess oil back to the pan).
Could the passage to the oil pan be blocked? After 5 years of research, I'm pretty stumped.
Engine runs fine otherwise...
F250_BreatherHose_Intake1.png
I’ve heard that my problem is quite common with this engine year (2005), especially on those with newer powerheads (2017).
Any speed under 5000rpms and the engine runs fine.
But creeping over 5000-5200 and I’ll start seeing the telltale exhaust smoke. I noticed this during the break-in procedure, which limited my WOT use, but I’ve been able to run it just under 5000 rpms enough that it doesn’t seem to be “making oil” from improper ring break-in (and the dipstick has never "Blown out"). But I’d still like to be able to open to WOT- just to make sure everything’s seated properly.
Currently at 300 hours on the new block.
Here's the common problem-
Oil is coming from the breather hose on the port head cover- then back into the intake manifolds where it gets sucked into the cylinders with each intake stroke. Excess engine oil is evident inside the manifold, plus in the breather hose and in small pools in front of the intake chambers where manifolds mount to heads.
But here’s the mystery-
The previous owner had apparently fixed this issue by installing the updated “T” connection on the breather pipe, allowing excess oil to drain back to the pan.
Before the rebuild, I never saw this smoke at high speeds, which leads me to believe something was reassembled incorrectly. I've made sure the oil level is not overfilled for multiple seasons now, so confident that too much oil is not the cause. The exhaust was also inspected and was in good shape (previous owner had replaced). Ring free and E-0 fuel have been used nearly exclusively since rebuild.
I know about the "anti-purge" kit that Yamaha made for these engines, but don't think adding a 3rd hose from to reroute oil to the filler cap is the solution (since I already have the added T connection to drain excess oil back to the pan).
Could the passage to the oil pan be blocked? After 5 years of research, I'm pretty stumped.
Engine runs fine otherwise...
F250_BreatherHose_Intake1.png
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