400R vs 450R
 

It seems like the 400R on the used market is a tougher sell than the 450R. I understand that everybody wants the latest and greatest and extra power/speed, but what other differences are there? Am I correct that the 400 requires premium while the 450 does not? Is the 400 just a detuned 450 giving it a longer life span? Do they use the same lowers or is the 450 more robust? The top end speeds do not seem allot different (5-10%?) but it sounds like the 450 accelerates harder? Does one or the other have mechanical or electrical issues that the other may not have? Thanks in advance!

Apples and Oranges. The 450 is a supercharged 4.6L V-8 that turns 6400 rpm. The 400R is a supercharged 2.6L inline 6 cyl. that turns 7150 rpm. 450 pulls harder, 89 octane fuel, faster on top end, way more torque for loads and planing. 400R has been a great motor overall and works well with multiple engine setups. The motors are close in weight, the 450 comes with a 1.60 gear and the 400R comes with a 1.75.

Joe

450R is nearly double the price.

400r is also supercharged.

And they both break propshafts constantly, that Mercury always has a shortage of. I waited over 2 months for a propshaft back in 2019 and a friend of mine has been waiting over 3 months now for one that he broke recently. Two years later and the story is still the same - even the new style propshafts break, and you can't get replacements when they do break. Just plan to buy a spare set of lowers and you'll be fine - that's what one of my friends has done. Me personally, I traded off my 400R boat for a 700/6 drive boat and haven't had any issues since. But, time will tell.........

Correct I didn't intend to mislead. I have 3 450s, and two 300Rs. Total of 800 hours run time roughly and have never broken a shaft. Thru hub propellers don't buzz the boat nearly as bad as an over hub, I also run Porta transom brackets on everything I own and lower the motors in rough conditions and when coming on plane. I think its lack of common sense in many cases of "not all" when prop shafts have broken.
ex: when you accelerate hard with your truck while pulling a load and it torque shutters; do you just stay in it and hope the drive line lives? In a drag car when you launch and get tire shutter; do you stay in it and hope for the best? NO, you let off and make another attempt. I have witnessed several drivers buzz their entire boat for 5 seconds or more in attempt to get on plane with high X dimensions and big 5 blade propellers on the motors (something is going to break).

Dale is correct that there is a supply defect with vendors supplying Mercury with prop shafts. I do have extra cases (in case).

Joe

And continuing to go up.

LET'S GO BRANDON.....

Joe

LOL, no kidding there was a picture Pete had posted from I think from key west. It was a 4 engine CC that was flying, props all the way out of the water, when you zoomed in the guy still had the throttles pinned to the dash.

I am sure doing that regularly will turn out well.

I have triple 400r on my center and was thinking about going to 450r. A very good source (sells lots of mercury outboards) told me to stick to my 400r for there reliability for what that is worth. Only issue I have had is when I had steering actuator issues, stick to gen 2. My engines are 2015.

What are hearing about 450s?

How many hours is excessive on 400s? Saw a CC that had over 1000 on a pair.

our friend has a 34 Nor-tech with 1800 on twin 400Rs, uses the boat every weekend. Was a yacht tender prior to his ownership.

Just told me 400r are more reliable and that 450's were breaking. Repair parts were issue this was back in June 2021.

I have a new respect for the 400. I have a buddy that runs his on his center console 100% throttle 100% of the time. He's really annoying to follow when you are just trying to cruise LOL

Joe P has it correct. The largest portion of pro-shaft or drive shaft failures is owner abuse/owner misuse... As for the rest of it... Well, there is no question that the 400R has proven more reliable all around than the 450R... Now that the 450s have been around a bit, many of the earlier issues have been solved and new production engines don't see those failures. yes, newer 450s are better than earlier ones.... The 450s are bigger displacement and carry weight a bit better than the 2.6... But they make less rpm and use a lot more fuel......the trade off for the torque the larger displacement provides... The 400R is a great engine.

Apples to apples same warranty period buy the 450R.
out of warranty buy the 400R