Re: need some answers please!!!!
I wonder if the revving up/down is because the pistons are getting tight in the cylinders and causing resistance (DUE TO OVERHEATING.) My engine seized so I went about digging into the problem: I renewed the impeller and thermostats too, but I also renewed the rubber finger-looking water diverters in the engine block (you see those if you remove the head, they look like a piece of rubber fuel hose a few inches long placed in there next to each cylinder in the water passages.) I was told by a local marine engine repair guy that those will wear and turn kind of egg-shaped instead of perfectly round and prevent water from passing through the block correctly. I know you don't want to do all that though. You did say that the water peeing out was cool, but I believe it should be at least warm. First rule out any lack of spark situation: clamp a timing light to each of the spark plug wires one at a time and just look at the light blink (if one of the spark plug wires blinks off at the wrong time compared to the others it may be a spark or power pack issue as well.) That is a simple/quick way to rule that out. If you know anyone with one of those infra red temperature gauges you just point it at anything to get its temperature (I got one from Harbor freight tools for $14.) I used mine when the motor seized again to verify that one of the cylinders was overheating. I just pointed the thermometer at each cylinder and looked at the reading...sure enough the "hot" cylinder was truly a higher temp. After mine seized I could still run slow/idle, but not go fast.
Not to get too long winded but my other motor acted like that when the stator ring(under the fly wheel) wore out. Green corrosion looking drip marks in that area under the fly wheel is a sign of that. Also a resistance check for that (stator/charge coils) told me mine was out (resistance was out of range of what the manual said) and when I replaced it it ran smooth again. I believe that would effect the advance/timing at higher RPM's.
Roger. Mt. Dora, Florida
I've been banging away at at least 4 older Evinrudes...I've picked up a few things over the years.
please help
