Johnson 5hp J5REEC backfire and hard start diagnosis

[peaceman56]

I bought a used Johnson 5hp that supposedly had less than 10 hours on the motor and it looks like it. Using fuel from the internal tank (new fuel 50:1) the motor took many (~20-30) pulls to start. Water from the tell tale was trickling out, not a good solid stream so will likely need a water pump. Once started, motor ran fine.
The next time, same story with many pulls but this time it back fired blowing the shift linkage rubber cover off the exhaust. Spark plug looks okay, light brown tip color, and is sparking when the cord is pulled.
Any thoughts on what else to diagnose or what could be causing this? Thanks for any thoughts or guidance.

 

[TrueNorthist]

Whelp... 11 year old, low hours, likely hung in a garage for months/years giving the ethanol loads of time to block up the idle circuit.

My guess: backfired due to extremely lean mixture detonating during start and upper body workout owing to same. Once on the main (high rev) it's peachy, yes? But probably still a bit lean.

Fouled carb and fuel system. Adding liquid mechanic won't work. Carb needs cleaning. Got a shop manual?

 

[peaceman56]

Sorry for the delay. I don't have a shop manual. I disassembled the carb and it looks spotless, the float looks good. it appears I am getting a lot of fuel to into the carb. The diaphrams in the fuel pump look okay, aren't deformed and I didn't see any holes or deformation. The hose that connects the fuel pump to the motor seems a little loose to me. New spark plug is wet after pulling on the motor awhile and I am getting minor exhaust puffs but no attempt to turn over.