47 post info

I don't have any user experience with this motor but I am glad to see you hopefully coming over to the Post family Wayne.

Did you mention to me that the saltwater cooling system has never been apart on that boat?

I have QSM 11's in a 48' Sea Ray and after 6 years of ownership am still very pleased with them. They do have some inherent issues to watch out for but every engine has flaws. The exhaust manifold leak, cracked coolant reservoir bracket, cracked trans cooler bracket (covered by Cummins) and making sure the original air filters didn't disintegrate and go through the engine are biggies.

Tony Athens is the expert on propping the QSM to prevent exhaust manifold leaks so I suggest googling "Propping the Cummins Marine QSM 11 to Prevent Exhaust Issues" to find a great article he wrote regarding the cause and how to minimize the issue. Essentially, you need to be propped to burn 18-19 GPH @ 2000 RPM. This is where I am now and my EGT's are in the low 900 F range.

My gaskets are original to the boat (2003) with 1000 hours. I have a leak on the port side that will be addressed in the spring. The damage had already been done by previous owners running at 1800, I was just trying to minimize further leaks when I started following Tony's recommendations.

My speed actually increased a bit due to running 200 RPM's faster. My stock wheels were 28x32 so I removed an inch of pitch and a few cup #'s. Running 1500-1800 is the worst as the EGT's skyrocket in that range.

I've heard of guys spending $8-10,000 to have Cummins do the repair. Depending on if new manifolds and heat shields are needed, they are $4,000 per set. I also know someone that spent $35k replacing everything on both engines including turbos. The kicker is that there's no guarantee that the repair will hold, there have been horror stories of the leak returning within as little as 5 hours. I'm using an independent mechanic and I own a machine shop so we will try to skim the manifold if possible.

I installed analog pyro gauges a few years ago and am converting them to digital using some Maretron devices this winter.

It's not ideal but I do it when needed. I'm sure it's fine for a few hours at a time.

Good luck on your search, I grew up on a 46' and a 50' and hope to get into a 53' someday myself.