Rust on Crankshaft throw Yamaha 4 hp 4 stroke

[maineiac5586]

Hi, I have a new to me 2000 yamaha 4 hp 4 stroke single cylinder. I bought it not running. It appears water got into it somehow. The gear lube looked fine but the motor oil was milky. I took the carb apart and it shows signs of silt. I am in the process of cleaning the carb. I did get it to fire up on startin fluid and it sounded fine. My question is when I look in to the oil filler hole (which is a rather large hole), I can see a gear at the bottom of the crank. Gear looks fine with no rust evidence but I can see the throw of the crankshaft has surface rust on it. This area of the crank is not submerged in oil when the oil level is full. Is this ok to run this motor with the surface rust on the crank? Should I run it till it is warmed up and then change the oil (doing this a couple times), I am just looking for opinions as the rest of the motor is imacculate. I may need to buy a new carb and before I invest in that I want to see people's thoughts as to the surface rust I see on the crank. Any help would be great, thanks

 

[maineiac5586]

Re: Rust on Crankshaft throw Yamaha 4 hp 4 stroke

anybody

 

[Grub54891]

Re: Rust on Crankshaft throw Yamaha 4 hp 4 stroke

I'd say just run it.without a good pic its hard to tell. Surface rust shouldnt be a problem. Just change the oil after the first run.
Grub

 

[99yam40]

Re: Rust on Crankshaft throw Yamaha 4 hp 4 stroke

If there is rust on the crank journals/bearings you know where that will lead.

You can tear it down and see how bad it is without spending much if you do it yourself