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mercury 40hp 1980 cranking now, but no combustion

That often happens, even with a good carb. I "bench test" every carb I rebuild, clamping it in my vise and priming it with a hose as hard as possible. If it leaks I lower the float level a 1/16 of an inch at a time until that nonsense stops.

Jeff

PS: Glad to hear she fired up. That means you're close to success.
 
kimcrwbr1 said:
You can also tap on the side of the carb with a wrench and get the float needle to seat. Not always but works in a pinch sometimes definitely getting close. I would take the cover off the thermostat housing once you get it mounted on the exhaust housing it should gush water when you start it. Definitly gonna want to go through the carbs if the primer dont get hard. One trick it just heard yesterday is to drain the float bowls after you disconnect the fuel lines put the plugs back in and fill the carbs with seafoam and let it sit overnite. Connect the fuel lines and then start it it will smoke for a bit best to do it upwind from the neighbor you dont like. Just kidding it will put on a good smoke show.
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ok so i ripped the carb apart it was blocked with bits of fuel pipe i got the needle out tested it like you said and all good, i put it on this morning and started first time.:D Next text giving it some throttle
 
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