Hi guys,
Re-powered my '87 Ranger 335V earlier this year with the aforementioned '94 2.5L 150hp XRi EFI off a newer Nitro. Serial # 0G017076. When motor was purchased compression in all cylinders was 125PSI. After rigging I installed a new impeller kit, new NGK plugs, fuel/water filter, and removed the entire oil injection system and installed the block off plate in the engine. I also removed/disassembled/cleaned the VST, and installed a new aftermarket high pressure fuel pump because the male/female spade connectors on the OEM Bosh pump had loosened up causing the pump to be too temperamental, so I installed one with ring/post connectors.
Motor has been treating me very well since installation right up until this past Sunday.
The "event"
I was taking off from the launch tournament morning when 1/4mile away the motor dropped power significantly. Backing off the throttle the motor picked up, and stumbled again when I got back on the throttle. Power loss dropped me off plane, and when I put the motor in neutral it died. I was able to start it back up, but it died again when I put it in gear. It would not start again after that.
The start of diagnosis
After a difficult (trolling motor only) tournament I came home to dig into the motor.
Spark
Installed new plugs and verified spark on all. I noticed that after cranking (attempting to start) 5 out of 6 plugs were dry (no fuel). The wet one seemed more like oily water than fuel/oil mix (lowest cylinder starboard side).
Compression Check
5 out of 6 cylinders all show 125psi just like during initial rigging.
The cylinder that I mentioned had that oily water (again lowest cylinder starboard side) checked out at 150psi! I verified this three times. More on this later.
Fuel
Testing the fuel pressure at the schrader valve I found that although the aftermarket high press fuel pump was being energized (and moving fuel) it was not building pressure (not even 10psi). Rigging the OEM pump back into place I immediately saw 39PSI at the schrader valve. Great, I found the problem and why the motor died/wouldn't run!
Run Test
Pump energized with key on, and engine fired right up, billowed out a large cloud of white smoke, and died in a few seconds. This repeated identically at least 5 more times. I witnessed the water pressure pee hole attempt to flow water out, but never produced a steady stream.
Uh Oh
Now my mind starts thinking about the "oily water" and the 150psi reading I found on that one cylinder (it would even spray fluid/vapor) out the plug hole when cranking.
What Now? Further investigation
Starting to prep to pull the starboard cylinder head to inspect. Not sure if I should expect a simple blown head gasket that I can replace and resurface head, or if this "event" on Sunday caused some permanent damage that will require a powerhead rebuild.
Anyone ever seen something like this?
I never would have expected to see cylinder compression increase with a potential blown head gasket. Very curious to hear any thoughts/advice.
Also, I'm having a hard time determining which head gasket is correct for this motor. If anyone is able to help it would be much appreciated.
Will update with photos/etc once starboard cylinder head is pulled.
Thanks in advance,
-Matt