Getting rid of yellow lines on imported STEP

[Mustang69]

Have this model I got from a manufacturer but for presentation it has yellow lines I cant remove

Am I stuck with them or is there a way to get rid of them?

[JDMather]

@Mustang69 

You have surface bodies. 
Convert to solid bodies or change Application Options Edge Display. 
Can you Attach the original file here?

[Mustang69]

Yes I know it comes up that way when opening the STEP file I got

Tried different ways but same result

How do I convert to solids?

Here are the original file

[Mustang69]

Hmm!! When I put in the part in my assembly it looks just fine!

Only when I open the separate part the lines appear.... Is there some setting differences in IPT or IAM files?

[JDMather]

I forgot to ask what version of Inventor you are using.

[Mustang69]

[Gabriel_Watson]

Unfortunately, you will have to rebuild/repair too much of this to make it work as a solid ("Stitch" it back together as a solid body instead of a surface). You are better off reconstructing another simplified solid that represents the largest geometrical boundaries of the part to use this in your assemblies.

I did a quick repair here in the Repair Environment and after a few passes using the Heal command I fixed the initial errors, but you still have underlying fundamental issues, which honestly happen a lot from vendor-type downloadable components you get online. Simply put, these are missing key surfaces that you have to add manually yourself, and it looks like there is at least a full day of work for you to fix this part:

[johnsonshiue]

Hi! If you don't mind them being surfaces, you can simply set the visual style to Shade (no edges) in the Part. It should look exactly the same as how it looks in the assembly.

Converting it to a solid requires additional work. Depending on the body quality and the gaps between the surfaces, you may or may not be able to convert it to a solid body.

Many thanks!