Reply To: 1980 12hp Evinrude Worktwin

[Don]

You are correct, this commercial model is a mixture of old and new pieces….New style 9.9-15hp powerhead adapted to an older style 10hp style midsection….It may not use the air box like on conventional recreational models..
Let’s start with your original issue, doesn’t pump water. Are you sure you have the gearcase deep enough in the water? I am assuming nothing comes out of the overboard telltale which is why you are assuming it doesn’t pump water….Is any water coming out of the exhaust relief on the midsection? This may just be an issue of the overboard telltale line being plugged up, which is very common. Try blowing back through the outlet nipple with compressed air. Or, perhaps removing the plastic nipple so any trapped debris can get out easily….But, be careful those plastic nipples break very easily, so be sure to use some long needle nose to compress the two locking arms inside the lower motor cover so the nipple will come down and out of the cover and can be removed from the overboard hose….
If no water is coming from the exhaust relief as well, then you indeed have some sort of pumping issue. Finding parts lists for these obscure commercial models can be tough, but I will look around……..D