Still can’t get my junk-box TD20 straightened out, so time to pursue new lines of thought..
From my previous work, I have clearly established that this motor has a bad misfire in at least one cylinder. It will only make reasonable power at high (near full) throttle settings, and things get progressively worse as the throttle is closed. By the point it’s reduced to half-throttle, it’s like one cyl. is completely cutting out – it runs very rough, shakes a lot and lowering it any further will stall it. Something is fundamentally wrong, here.
First off, on a TD20, there are two 1/8" holes drilled into the starboard side of the brass downtube, just below where the large circular clip rests in its groove. What is the purpose of these holes? Is it possible that water might exit from these holes – and if so, what would that indicate?
Secondly, there seems to be water running down the outside of the downtube.. it may be (partially) coming through these holes, but there’s also more water issuing from someplace higher up on the engine. I can’t quite tell where it’s escaping, but it’s somewhere in the region where the downtube meets the top of the transom bracket. There’s a bakelite bushing / washer there, you likely know the area I’m referring to..
It’s not the stream from the tell-tale port, which btw seems pretty good – very comparable to my ‘good’ TD20. So despite the noticeable amount of water that +is+ leaking out (of somewhere it’s not supposed to) it doesn’t seem to be starving the motor for cooling flow.
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