Considering larger boat with 12v92's

It depends. If someone reputable did the rebuilds they should be good to go. Every Sportfish I've run with the exception of 1 of them, needed rebuilds on the 12v92's every 1000 hours. One 58' Striker I ran, had them major overhauled 6 times. Another 1994 54' Hatteras had them rebuilt twice in 1980 hours due to catastrophic failures. The only SF they lasted in was a 1987 63' Ocean and the origional set went 5500 hours before majors. I'm not a 12v92 fan. I just ran a 2002 65' Hatteras SF enclosed bridge repo, it had 3400 hours on CAT 3412's, it needed paint, a generator and this' and that's but the interior was very clean and the boat cruised 28 knots and sold for $375k with a tuna tower, davit and newer whaler on the boat.

Overhauled? Get all the details of what was R&R'd, what else was done and of course by whom- otherwise it didn't happen. 1000 hours is very few- meaning the boat sat and did nothing for quite some time. That can be bad as well. The last'92's were installed in the '90's .... until you (meaning "we") have more info a good decision regarding which engines are "better" cannot be made IMHO.

It's true 1200 hours on 20 year old motors is only 60 hours a year.....or some years of just sitting, it can be very bad also. I would find out who rebuilt the 12v92's in the other boat.

I have a 54 Bertram with 1080 HP 1292's, they had 2190 hours on them when I bought the boat in May. We have put about 150 hours on the boat this summer fishing and cruising with zero mechanical issues (knock on wood!). My port engine smokes on start up but clears immediately when in gear, other than that they run incredibly smooth. They don't use or leak oil which is very un-Detroit like in my experience. Fuel efficiency is a completely different matter. My plan is to run the boat south to Cabo and spend a season or two down there, prior to that I'm going to have both motors majored.

On either set of 92's make sure the coolant (G93) or water additive (novakool) has been changed every 2 years or 3 years at the very very most. It's crucial on Detroits.

If they did not smoke on start they have block heaters and they are on, or they were started and run before you arrived. Either way you should see them start when they are cold for a little better idea of the condition.

I've run some sets of 12v92's that didn't smoke on cold startup. But it's boats that were used, used often and run at cruise often.......a week later could start them up and wouldn't smoke.......but it's more of a rarity. I would wait till your boat sells before buying the next. ALSO, I would buy a pill bottle of the Detroit Diesel coolant test strips and test the coolant in each 92 boat you're looking at.....it's a paper stick you just open the expansion tank cap, get it wet with coolant and a minute later it will tell you the concentration.

Usually mid ships in the block about halfway up from the oil pan to the heads. But, just put your hand on the engines and look at the coolant gauge before the engine is fired up should tell you whether it was just run or has block heaters on. 12v92's usually take a full day to cool off to ambient temperature if they've been run.

You should have a breaker box somewhere in the ER which allows you to shut off each engines heater. Also there should be a breaker at the main panel which is labeled block heaters. The heater is similar to a water heater element since it heats the coolant, and on my 16-92's it was located on the right back (when viewed from the rear) about 2/3 forward and just below the heads. There is a small box which had leads to the element; it turns the element off and on dependent on temp.

When inspecting a boat or for survey and seatrial you want the engines cold or ambient temperature. The amount of smoke and color of smoke will give you an indication of what condition the motors are in by how much they smoke and for how long after startup. If it smokes blue and then clears in a minute it's usually valve guides, if it smokes for 10 minutes or so and it's blue or grey, more like piston rings but could be injectors too if it's grey, if it smokes very little then the engine is very healthy. Also can tell by the sheen the motor is putting on the water with a cold start. Granted, DDEC's and other computer controlled engines usually smoke very little on cold start up unless something is seriously wrong.

You can start your engines in the Alaska winter with no block heaters? Wow.
Captain J in correct in his assessment of cold start ups and smoke.
BTW I meant to say "right bank" post of the heater location- not "right back".