What Size (I.D.) Hose Do I Need?

[JoLin]

I may have a high-speed overheat issue on my port-side 4.3. Haven't confirmed it yet but I want to get some things ready for when my friend and I water test it to confirm. I have an IR gun, and I want to replace the t-stat housing to starboard manifold cooling hose with a clear hose to check for air at 3,000 rpm, per Merc's troubleshooting bulletin.

I'm not at the boat, and just wondering if anyone knew offhand what size (I.D.) hose I need for the connection. I can pick it up before I go back to the boat. Thanks.

 

[Bondo]

Ayuh,..... 1 inch,....

 

[JoLin]

Thanks, Bondo. You saved me some travel time.

 

[Bt Doctur]

But in most cases the water pump base is sucking in exaust gas