Mercury 400R - experience & life expectancy?
 

I'm looking at a boat with Mercury Racing 400Rs with 400 hours. What's everyone's experience with these motors? What can i expect for life expectancy with regular routine maintenance? Is there any difference between the 400 and 400R other than the raise rev limiter? I see a lot of info on the Verados but not the 400s. This would be my first outboard boat so was hoping to get some feedback on these motors. Thanks!

Did you get any replies?

I would be curious to hear the same..

Based on the rule of thumb that a Mercury fishing engine is built for "high hundreds" of hours, which was at least the case before the Verados, the 400Rs in the original post should have at least half to two thirds of their lifetime remaining.

By the time the 400R came out, the bugs in the Project X supercharged I6 4-stroke platform were ironed out long ago. Compared to stern drives, 400Rs should be very trouble free. Anecdotally, those of my friends who have run them have been happy with them. You can get another 40 hp or so out of them as well if you find someone who can do some magic to the ECU. Mercury has clamped down hard on that practice.

Gearcases are probably the weakest link.

The V8 platform on which the 300R and 450R are based is a big step forward, though.

Great info!!!

Time seems to be a factor in saltwater environments. The Yamaha 300, Suzuki 300, and all I6 verados seems to be good for at least 1000 hrs. In gentle more frequent use they could maybe go 1500-2000.

What are you putting them on?

In a high X dimension app that comes out of the water. I’d expect a lot less than what I said above. I’ve heard of a verado issue with barking them and creating boost spikes, never seen it discussed online though.

Of the ones I'm personally aware of the only issues have been with gearcases. Still amazed they hold so little gear lube.

Is there any way to check the service records, scan etc? I was told that they HAD to have the oil changed regularly as scheduled or you would be looking at new powerheads.

Modern 4 stroke outboards go way more than 1500 to 2000. I have personally seen yamaha 300's at 4300 hrs being sold to repower. Engines still ran fine.

Life expectancy
 

Yamaha 2 strokes were designed for a 2000-3000 hours.

Never seen it on a non commercial application. Those put on many hours in a few years due to running daily. I figured those outliers aren’t relevant to a pleasure boater that runs 50-200hr a year and never gets to 2000 before corrosion related failure modes become common.

Those old motors are the only 2 strokes you still see consistently.

Bulletproof.
They still sell them brand new over here but real simple……. Carbs not fuel injected, pre mix not oil injected. 🙂
Flat out all day, pushing commercial speedboats. They’re also less than half the price of a 300 4 stroke.

Yamaha pretty much owns the commercial 4 stroke market here but there are a few 300hp Verado (straight 6 version) powered boats. I’ve heard they run 3,000 plus hours hard use but more expensive to buy and service.

RR

Yamahas also come with dogsh1t tiny props that are keeping some load off the LU and engine.

Never really thought of that. Those high hours are commercial use. I have 850 hrs on 2006 275's in salt and they still run like new. Couple rubber boots to replace and clamps but besides that nothing major. So just saying that corrosion and seals dont seem to be a big issue.

Thats old! I don’t see many 275s still kicking. I’d say you’re more of an exception than the rule.

Really? How old is "Old"? I was just paying attention to this at Peanut and the ICWW yesterday and thought there were a zillion merc 2 strokes. By "old" Im talking early 2000's stuff 2002-2007ish. I would assume most people went to 4 stroke but when I look, there are a ton of 250's old and new around here. Of course there are Suzukis and Yamaha but Merc still has the majority. Not talking triple and quad setups. Mostly single and twin fwiw...

I had a very low hour 2003 yamaha 9.9. I bought it used around 10 years ago. I didn't put many hours on it and used salt away every single time I got home. It rotted from the inside out. Looked like new from the outside. I think I posted pictures of it on this site. I'll see if I could dig them up.

I might be exaggerating, maybe I don’t notice them as much? Maybe a different market around here. St pete beach area doesn’t lack high end hardware. I see more smaller older boats over at beercan island for sure

Buddy has a South Bay tri-toon on LOTO with a 275 V-Rod with over 1,000 hours on it now. Still going strong.

When we lived in Fla I saw stacks of dead Yammi 2 strokes everywhere.

Used to post pixs of pallets of them stacked to the roof of the shops on SF for the Yammi nuts over their!

When everyone was gah gah over their 4 strokes, I helped a couple of my neighbors w/theirs.

One was a 5 yr old 250 that my neighbor bought new, kept on a lift and flushed after every run.

He came and got me to ck a water leak coming out the rigging tube after a day of offshore fishing.

I tracked it down to a nickel sized hole, corroded through the top of the block, under the flywheel.
Was spraying the ignition w/saltwater all the way in.

Told him his options and was not a happy camper.

Neighbor #2 had a 3 banger Yammi 4 stroke, similar scenario.
Bought new, lift stored, flushed and a log book of maintenance.
Neighbor passed and I helped the widow sell the boat.

It blew up on the sea trial!
The Fla heat caused condensation (motor was covered) to form inside the motor which then drained into the oil pan.

The bearings, rings etc evidently prefer oil to water.

S Fla is where motors go to get tortured and die!

Short answer…they haven’t been out long enough to get statistically relevant data. Atleast by the small sample size of people that own them on this website.

old v6 yamahas 2 stroke ran great until you had to take them apart. you couldnt, the threads came out with the bolts. Porous aluminum made from recycled aluminum. They ran great many hrs but after a few years , not hours, they where so corroded you coudnt take them apart, they fell apart. that was salt motors, i worked on them for decades. I hope the four strokes arent cast from junk aluminum.

400R are great engines. The verado's get hate from time to time but I always see them with high hours. 2000 hours shouldn't be a problem as long as they're maintained. Gotta love that 7k rev limiter... spin to win!