Re: Johnson TD20 / TN26 etc. – T-shooting Part 2

[legendre]

Why thank you very much, guys! Much appreciated.

So here’s the update: I put in the new head gasket, and it had essentially no effect. There’s still something very fundamentally wrong with this engine, and it’s at the short-block level. Starting to seriously consider things like crankcase leakage, particularly between the bottom & top end (primary compression leakage).

Crazy enough, the dang thing still starts on the first pull, practically every time!

But there’s still this issue of water running down the downtube, and apparently sputtering out of the two vent holes in the same tube. I mean if there’s a base gasket leak, sure, it might leak water externally – but could it be leaking enough water into the exhaust port to cause this issue? Do these motors still run OK with a bad base gasket?