Impeller damaged by fuel 70 HP Mariner

[ml357]

I have a 1981 Mariner 70 HP outboard that I just replaced the impeller and housing 2 weeks ago. The impeller quit working again after about 4 laps around the lake on two different trips. (Small 43 acre lake) Dropped the lower unit and removed the impeller housing and found the impeller destroyed and soft and smells like gas. There is some gas residue in the exhaust tube. The unit idles and runs good at WOT. The new exhaust tube seal is also swollen and soft. I could not find any fuel lines leaking. I pumped the primer bulb up with the carb cover removed so I could see inside the carb. I did not see any fuel leaking inside the carb. Can the fuel pump leak into the lower unit to cause this?

 

[racerone]

Is this a factory new impeller???-----Or some other product found online ?

 

[ml357]

Other.

 

[racerone]

Install a factory impeller.----I believe that the issue will not happen with quality parts !

 

[ml357]

Why was there gas in the impeller housing? The impeller that was put in last year was factory and it did not last either with very few hours on it. The O-Ring (centrifugal slinger) on top the impeller housing on the drive shaft also had gas on it and was swollen up to twice its size and very soft.

 

[racerone]

Inspect carburetor float valves.----Inspect / replace fuel pump diaphragm