Looking at a boat out of town and trying glean some info. What does a newer 383 stroker have for a cooling system? Is it a closed or open system? I'm sure it's a dumb question but couldn't find a ton of info.

also, what's the preferred WOT RPM on these? Boat is currently running a 21 apollo and is running at 5200 wide open.


Picture of the motor from the ad:

Looks like it is open cooling, I don’t see a heat exchanger.

Cooling systems go either way...all depends on the setup when installed. That pic is an open system...i don't see a heat exchanger anywhere in the pic for it to be a closed system.
RPM would be limited by the IGN system type...i believe most of the stock merc stuff limits it to 5400rpm max but that also drops depending on what prop you are running and what drive ratio...5000-5200 seems about right...

See specs here:
https://samerwebapp01apncus01.azuree..._8m0080494.pdf

its raw water cooled

Ok great, thanks gang. Owner said he was getting his best speed at about 4900 but WOT was running 5200. Sounds like it's propped pretty well on paper then.

Ignition interrupt tells me it's an Alpha Drive... am I right?

Bravo drive on an 88 Formula 242.