Honda GX120 on pump

[Dustin4185]

Gentlemen, we have a Honda WB20X water pump with a GX120 engine. I was filling our nursery tank and everything was going good then it backfired and wouldn’t hit a lick! Pulled plug at the shop and it has fire. Won’t hit on ether either. I didn’t check compression, but will tomorrow. Fresh gas, but wasn’t mine. I loaned it to someone and they filled it up . This pump/engine is a 2008 and has had a rough life pumping water and chemicals in an ag situation so I’m not mad if it decided to drop a valve or something like that, lol. Where do I start?

 

[066 redeye]

Fly wheel key.

 

[Dustin4185]

Fly wheel key.

Hmm, didn’t think of that. It very well could be especially since it happened right after I increased the throttle since a storm was coming.

 

[GMB74]

Take a fuel sample. Water or Diesel in the tank?

Did it over-rev and bend a pushrod/ pop off a rocker?

When taking a compression reading, remember the compression release is going to cause a low reading. A reading of 50 PSI is still ok. The old thumb over the sparkplug port test is just about as accurate as a gauge reading.

 

[Creaky limb tree care]

These aren't two stroke engines so they are quite tough, check oil level, change plug and fuel first.

 

[farminkarman]

I’ve lost coils in a few. Definitely check the simple things first like spark.

 

[Dustin4185]

I’m thinking a fuel issue. I drained the tank and it doesn’t look the best. I was waiting to get a plug before I try everything again. Pulled the rocker cover and everything seems fine. Flywheel key is in place. Coil and fly wheel are rusty. I guess that’s part of it being a pump. I’m going to clean everything up and give it a shot tomorrow. Is there anything that can be put in the flywheel to keep it from rusting?