My previous post became long and bloated with unimportant info, so I'm going to start a newer, more concise version.
I've got a 93 140 V4(VJ140TLETC) that is badly missing at idle. Video here: http://www.youtube.com/watch?v=PeyIG9vpIjM
Here's what I know so far:
Currently I'm running the engine on a portable tank of premix, so it should be getting double oil, though I don't believe this is what caused the plugs to look bad, as I just recently switched to premix.
The problems seem to be coming from the starboard carbs/port cylinders. The engine sounds like it's running lean, and spraying starting fluid (with lubricant) down the throats of the starboard carbs causes it to pick up and run better. The fouled plugs make me wonder if this is actually true, or if the lower flashpoint of the starting fluid is masking the problem.
I've rebuilt the carbs so many times now that I'm pretty sure they're all clean. One thing I would like to know is what path fuel takes through the carbs at idle. Does it still go through the big main jet? Or does it go up the brass tubes into the funny passages under the side cover?
The one system I haven't looked at yet is electrical. I'm planning this weekend to get the multimeter out and to start checking ignition systems. My theory is that maybe I'm getting weak spark at idle. Its my assumption that I can test this by holding a plug wire away from a plug while the motor is running and seeing if I get an arc over a half-inch gap. Is this a valid hypothesis? Should I think about the power pack or stator?
Should I be concerned about the VRO pump? I pulled the air line off a while back and it was dry inside. VRO is clearly getting oil to the motor(it would have siezed by now), though the motor barely smokes at all, even when cold. The exhaust housing in the lower unit is heavily coated in carbon. Is it possible to have the VRO system injecting too much oil without the engine smoking? The carb bowls are always full of fuel, and squeezing the primer bulb while it's running doesn't help.
I've got a 93 140 V4(VJ140TLETC) that is badly missing at idle. Video here: http://www.youtube.com/watch?v=PeyIG9vpIjM
Here's what I know so far:
- Motor runs fine at speed
- Compression is good, 145 in all cylinders
- New water pump and thermostats
- Carbs rebuilt 3 times (and even tried with brand new F suffix adjustable carb upper bodies)
- New plug wires
- New intake manifold gasket
- New reed box gaskets
- Reed boxes all look good
- New throttle body gaskets
- All 4 spark plugs look somewhat fouled
- Carbs are non-adjustable
- Link/Sync seems fine
- Idle timing (as best I can check) seems fine
- Engine has been decarb'd recently
Currently I'm running the engine on a portable tank of premix, so it should be getting double oil, though I don't believe this is what caused the plugs to look bad, as I just recently switched to premix.
The problems seem to be coming from the starboard carbs/port cylinders. The engine sounds like it's running lean, and spraying starting fluid (with lubricant) down the throats of the starboard carbs causes it to pick up and run better. The fouled plugs make me wonder if this is actually true, or if the lower flashpoint of the starting fluid is masking the problem.
I've rebuilt the carbs so many times now that I'm pretty sure they're all clean. One thing I would like to know is what path fuel takes through the carbs at idle. Does it still go through the big main jet? Or does it go up the brass tubes into the funny passages under the side cover?
The one system I haven't looked at yet is electrical. I'm planning this weekend to get the multimeter out and to start checking ignition systems. My theory is that maybe I'm getting weak spark at idle. Its my assumption that I can test this by holding a plug wire away from a plug while the motor is running and seeing if I get an arc over a half-inch gap. Is this a valid hypothesis? Should I think about the power pack or stator?
Should I be concerned about the VRO pump? I pulled the air line off a while back and it was dry inside. VRO is clearly getting oil to the motor(it would have siezed by now), though the motor barely smokes at all, even when cold. The exhaust housing in the lower unit is heavily coated in carbon. Is it possible to have the VRO system injecting too much oil without the engine smoking? The carb bowls are always full of fuel, and squeezing the primer bulb while it's running doesn't help.