New! Mercury 250R and 300R

**JPEROG** · 05-22-2018, 04:01 PM

These motors have been a very long development process and they have tons of hours logged on them. Take look at the new small block automotive engines and look at what they are doing. The Ford eco boost has 100% proved my prediction wrong. I know of one that has pulled a 20 foot enclosed trailer for 90% of the time its in motion and he just hit 300K with it. Never had a turbo replaced or been into the motor.

Joe

**mr fun** · 05-22-2018, 09:14 PM

Joe, that is what I've been thinking over the last several days. the engine in my F-150 is a 4.6 liter, modified chip, pulls to well over 5 grand before shifting. it lives, so i'm thinking this could be a platform that could be enjoyable. my question is how long can i depend being able to depend on it's usefulness before a rebuild. a car motor is used daily, and nowadays we're looking at 300,000 miles realistically if properly serviced. how many hrs is that?

**FMP** · 05-22-2018, 09:44 PM

Always liked this 4.6, 6000+ easy

**JPEROG** · 05-22-2018, 09:47 PM

At 70 miles an hour that would translate to 4200 hours. No car or truck goes anywhere near that fast for that long so my guess is that it would take the average guy 6 to 7 thousand hours to put that kind of mileage on the clock.

Joe

**AZMIDLYF** · 05-23-2018, 12:02 AM

Did you mean that many RPM for that long JPEROG? Most auto engines are loafing along.

**FMP** · 05-23-2018, 10:22 AM

Most vehicles range 90% of the time below 2500-3000.

**Rynobull** · 05-23-2018, 07:04 PM

Say 250,000 miles and I bet the average speed is closer to 45 or 50 mph when all the idle time and stop and go is factored in. That's 5,000 hrs. Today's vehicles cruise at 75 mph in the 2,000 to 2,200 rpm range. Account for acceleration, downshift when using cruise control and all that. Let's say a realistic average is 3,000 rpms.

5,000 x 60 x 3,000= 900,000,000 revolutions.

If they average 4,500 rpm in a marine application, that would be roughly the same revolutions as 3,333 hours.
900,000,000÷60÷4,500= 3,333

Not too bad....

And I get that higher rpms will stress a motor faster, but these engines will also run much cooler than car motors which should help them live longer. I see 3 to 4k hours no problem!

**nitro_rat** · 05-23-2018, 07:13 PM

An engine in a car cruising in overdrive at 2,200 RPM’s is doing so almost completely unloaded using something like 25 hp.

An engine in a boat cruising at 2,200 RPM is doing so under load and using basically however much horsepower it makes at that RPM.

It’s a totally different situation. The bearings, rings, and even hard parts like rods and cranks are under way more load in a boat. It’s more comparable to the way an aircraft engine is loaded than a car engine.

One advantage the boat has is an unlimited supply of cooling water...

**Rynobull** · 05-23-2018, 07:22 PM

I do realize what you are saying and I'm sure if we compared bearings to bearings, cranks to cranks, rods to rods.... etc...

These new marine motors will have ultra strong components. I know you will agree with me here!

**JPEROG** · 05-23-2018, 08:17 PM

Even if they last 1/2 the amount of hours that we are talking about its a life time to most guys. The other thing to consider is how much time a boat motor spends at above 4000. I have run the DDT on a lot of motors and I am always amazed at the number of idle hours. To hold a boat at above 4000 rpm for any length of time (in a boat under 25 feet) you need to be on a river or really big lake with nice conditions. Between all of the boats that I ran last year I logged just over 300 hours combined and I am usually on the water 4 times a week.

Joe

**mr fun** · 05-23-2018, 08:30 PM

all i can think at this point is the street guys are doing amazing things with American and import motors, guess it's time for me to date me. technology is definatly marching foreward. i'm sure merc is on the leading edge of what they are distrubiting, the real red flag to me is salt water as a cooling agent. (spelling foul as i'm in the middle of an argument with my wife) fun out

**Risco** · 05-24-2018, 04:48 AM

Originally Posted by Rynobull

Say 250,000 miles and I bet the average speed is closer to 45 or 50 mph when all the idle time and stop and go is factored in. That's 5,000 hrs. Today's vehicles cruise at 75 mph in the 2,000 to 2,200 rpm range. Account for acceleration, downshift when using cruise control and all that. Let's say a realistic average is 3,000 rpms.

5,000 x 60 x 3,000= 900,000,000 revolutions.

If they average 4,500 rpm in a marine application, that would be roughly the same revolutions as 3,333 hours.
900,000,000÷60÷4,500= 3,333

Not too bad....

And I get that higher rpms will stress a motor faster, but these engines will also run much cooler than car motors which should help them live longer. I see 3 to 4k hours no problem!

When I used to work on diesel trucks the 2004 and newer have hour meters In the dash you be lucky to see a average over 25 mph. As for a lifecycle of the newer motors look at required maintenance book should list hrs and intervals to give you guys a idea of how long it was built to last. Knowing that mercury will raise the power of the v8 I’m pretty confident the 250 and 300 will be generally reliable that being said there always gremlins with new products.

**John Hice** · 05-24-2018, 06:58 AM

I think they are on the right track with a great product but only time will tell. This was built from the ground up as a marine application with many years of experience behind it. I have been a marine diesel mechanic for some 40 years and seen many engines come and go as highway/marine conversions. Some work and some didn't! Take the Cat 3116 & 3126, well over a million miles in highway use but most didn't make it past 300 hours in a boat. Almost put SeaRay into bankruptcy. In a marine application the boat is always going up-hill and the 3116-3126 couldn't take the sustained heat in the top-end and turbo-chargers which ended up in premature failure. There were others but these two stand out.
I look forward to seeing where Mercury ends up with this setup. The only thing I don't like is the look of the cowling. UGH

**JPEROG** · 05-24-2018, 05:57 PM

I don't think the looks of the cowl should concern you too much John. You will only see the back for of them for a couple seconds as you roll up on them and they have some nice bright color so you don't run us over.

Joe

**Capt.Insane-o** · 05-25-2018, 12:14 AM

Originally Posted by DRAG'N FEVER

I think they are on the right track with a great product but only time will tell. This was built from the ground up as a marine application with many years of experience behind it. I have been a marine diesel mechanic for some 40 years and seen many engines come and go as highway/marine conversions. Some work and some didn't! Take the Cat 3116 & 3126, well over a million miles in highway use but most didn't make it past 300 hours in a boat. Almost put SeaRay into bankruptcy. In a marine application the boat is always going up-hill and the 3116-3126 couldn't take the sustained heat in the top-end and turbo-chargers which ended up in premature failure. There were others but these two stand out.
I look forward to seeing where Mercury ends up with this setup. The only thing I don't like is the look of the cowling. UGH

Don't remind me of those sea ray/ cat nightmares.

This next gen cowl thing going on though is total ass.