Troubleshooting Intermittent Problem

[AndyB]

Howdy all,
Just joined, looking for some confirmation before I start spending money...
I bought a used Tracker with a 1987 Classic 50 Merc outboard last year. The engine seems to have low power. With just me, I will gradually get up on plane and run about 5000 rpm. If I fill the live well, sometimes no plane. More than one person, no plane. Engine stays at about 3k rpm.
Some trips worse than others. I found a slightly corroded coil, replaced, ran good for a while (maybe wishful thinking on my part).
I have done the following: rebuilt the carbs (I have an odd carb with no integral fuel pump). I disconnected the oil injection and I mix the oil (not in response to this problem).
I decarboned the engine last year with Seafoam.
I believe the problem is ignition.
I measured the stator resistance as follows:
red to red/white = 151 Ohms
blue to blue/white = 6670 Ohms
DVA red to red/white (cranking) = 48 V
DVA blue to blue/white (cranking) = 309 V
DVA red to red/white (running - idle) = 140-170 V
DVA blue to blue/white (running - idle) = 310 V
Trigger DVA to ground all 4+ V
Purple to white = 11-12 DVA running
Brown to black = 11-12 DVA running
In the manual I have, under "Engine will not accelerate beyond 3000-4000 rpm" section, it states "Connect a DVA meter to the red wire and red/white wire and do a running test. The DVA voltage should show a smooth climb in voltage and remain high through the RPM range. A reading lower than the reading on the blue wires indicates a bad stator."
The boat is on the trailer, and I am running on the hose, so I can't rev too high, but, the DVA voltage never exceeds the blue wire voltage.
I am tempted to replace the stator. And if I have the flywheel off, I may as well replace the trigger.
Any thoughts?
Thanks
Andy

[boats.net]

Have you checked compression? Has the prop been replaced or repaired recently?

[AndyB]

I left that out. I have checked compression in all cylinders (good), and I replaced the prop, even though I didn't really think I needed it. I played with taking the Doel fin on and off. Not much difference. I am pretty convinced it is timing or something else with ignition. I suppose I will have to go the lake and run around with a timing light and the DVA meter to see what I can see.

[boats.net]

It sounds like it needs a smaller pitch prop, might try dropping one prop size to see if makes an improvement.

[AndyB]

Well, the plot thickens...
I went to the lake today with a friend. WOT on the trailer, 3000 rpm. Sounds good, but no higher. Should it run at 5000-5500 rpm on the trailer in gear?
I checked the ignition system (in gear), seems to be working properly. So now I am starting to second guess myself. Perhaps this is fuel related after all. We launched the boat, and ran around the lake some. WOT was 3000 rpm, boat not up on plane. My buddy went and sat up front (to redistribute the weight), and the boat slowly acclerated to 4100 rpm, and kind of got up on plane.
Went back to the ramp and came home. I pulled the carbs, and went through them. I replaced the gaskets last fall. The carbs were/are clean, with no discrepancies noted. The only thing I can find is the float level. Upside down, I can set it as it is described in the manual, basically float is level with bowl. Right side up, manual says it should be within 1/32-1/64 above the main jet. Mine is lower, but I can find no way to raise the plastic float (has a plastic tab that controls height, and I do not intend to try to bend that).
I suppose I should buy the carb kits and replace everything. The fuel lines appear fine. The filter(s) appear fine. I guess I can buy another tank and line to eliminate that. I disconnected the fuel pump and cranked the engine, fuel came out. Not sure how much is supposed to come, but it looked ok to me for cranking speed.
Has anyone else run a motor in a tank or on the trailer in gear? How fast should the engine go - should it turn full rpms?
Thanks
Andy

[AndyB]

Well, I bought another fuel tank and fuel line, and it didn't help. I am back to the ignition. What jumps out at me is the red to red/white Ohms out high, and the voltage is low (at least according to the troubleshooting guide), provided it is supposed to be higher than the blue to blue/white wires. So I think I will order the stator. And if I am replacing one, I probably will go ahead and replace the trigger at the same time.