1981 Motor Boating Magazine v20 with Merc 200hp

[bigshrimpin]

Check out the performance specs from 1981.

https://books.google.com/books?id=QK9jo73c5gUC&pg=PA67

[bradford]

Sweet!

I love my 150 for gentle mid range cruising, but always thought I'd like a 200 better for hauling the mail.

Their findings of going up 1.5 inches on the transom mounting I find to be also true on my skiff with a hydraulic jack plate, 1.5 is the sweet spot. Would like to try a four blade BRP Rogue or Solas Titan prop though for more stern lift plus she likes to porpoise some on the top end.

Can't believe they ran over an oyster bed on purpose just to get numbers with a damaged prop. WTH!

[Destroyer]

That's a great article, and it confirms what I've thought for a long time. 200 hp is simply better. (Think of a house air conditioner.. too small a window unit and it has to run all the time. Make it bigger and it works less to deliver the same cooling.... in other words, it's more economical) The same with a 200 vs a 150 on our size boats.

At any rate. it was a good article and I thank you BigShrimpin for finding it. I just wish they mentioned what pitch prop they were using in their tests. That would have helped a lot.

[bgreene]

Now imagine the benefits of 300 hp !

But seriously, a couple of things......
1. engine weight - they show the 200hp as lighter than the 175 and 150. I believe it's backwards. Also, at less than 400lbs, all three of these engines are considerably lighter than many current outboards.... my etec 200 hp is more like 525 lbs.

2. engine weight - based on the reality of current 200 hp weight, the 150 truly is lighter, and this has some advantages too........

So, for those with 150hp pushing V's....... that's a very fine choice for these boats, with over 40mph top end, and less weight on the transom.

Engine height comment - I moved one hole further than my shop rigged, and still have 1 hole higher remaining. Might try it.........or not.

[THEFERMANATOR]

Originally Posted by Destroyer

That's a great article, and it confirms what I've thought for a long time. 200 hp is simply better. (Think of a house air conditioner.. too small a window unit and it has to run all the time. Make it bigger and it works less to deliver the same cooling.... in other words, it's more economical) The same with a 200 vs a 150 on our size boats.

At any rate. it was a good article and I thank you BigShrimpin for finding it. I just wish they mentioned what pitch prop they were using in their tests. That would have helped a lot.

The cooling analogy isn't a good one as it has been proven time and time again that a 90-95% duty cycle of an A/C unit is MORE efficient than an oversized unit that doesn't run as much. If an A/C is oversized, the unit doesn't run enough to remove the humidity, yes it runs less, but it uses more electric while running, so you end up using just as much electricity, but don't remove as much himidity leaving your home feeling cold and clammy inside. Going oversized is a common misconception though. And it should be of note that a 1981 200HP MERC is actually a 175HP MERC by todays standards.

Originally Posted by bgreene

Now imagine the benefits of 300 hp !

But seriously, a couple of things......
1. engine weight - they show the 200hp as lighter than the 175 and 150. I believe it's backwards. Also, at less than 400lbs, all three of these engines are considerably lighter than many current outboards.... my etec 200 hp is more like 525 lbs.

2. engine weight - based on the reality of current 200 hp weight, the 150 truly is lighter, and this has some advantages too........

So, for those with 150hp pushing V's....... that's a very fine choice for these boats, with over 40mph top end, and less weight on the transom.

Engine height comment - I moved one hole further than my shop rigged, and still have 1 hole higher remaining. Might try it.........or not.

The 200HP 2.4L MERC WAS lighter than the 150 of it's day. The 200HP engine was a chrome bore or nicasil block whereas the 150 was a steel sleeved engine. And without all the extra crap on outboards, they used to be pretty light. My 225 EVINRUDE only weighed in around 465 pounds or so for the big V-6. SUZUKI had a 225HP outboard with fuel injection, dual plugs, the whole shebang, and it only weighed 470 pounds.

Keep in mind these tests are with carbed 2 stroke engines where raw fuel going out the exhaust ports was common place. The 2.4L engine ALWAYS had an edge over the 2.0L engines, so these results are what I would expect to see. Modern DFI or 4 stroke engines have changed these kind of results quite a bit.

[bgreene]

Interesting info as usual from our assorted group.

I just don't want our V guys with 150 hp to start feeling bad !

My " enormous" 3.3 liter, 200hp HO Etec..........still only runs the V21 to 49+/- mph, so is no faster than the old, light mercury 200.


I bet you're correct THERM, today's DFI 150 likely more fuel efficient than 200 DFI.

[Destroyer]

Originally Posted by THEFERMANATOR

The cooling analogy isn't a good one as it has been proven time and time again that a 90-95% duty cycle of an A/C unit is MORE efficient than an oversized unit that doesn't run as much. If an A/C is oversized, the unit doesn't run enough to remove the humidity, yes it runs less, but it uses more electric while running, so you end up using just as much electricity, but don't remove as much himidity leaving your home feeling cold and clammy inside. Going oversized is a common misconception though.

I did specify a small window unit. While I agree with you on a whole house unit using more electricity that's not really the case with small window units.
In many cases the difference between a 4500btu or a 5000btu is the size of the evap coil with the compressor being the same size for both of them. The electric usage is less per btu with the larger unit while achieving the same RH decrease and cooling. And of course, a case could also be made that using several window units to cool a home will cost more than running just one large central unit to do the same thing, because the central unit will be running one compressor on 220v while the window units will be running multiple compressors at 115V. (But that's no longer comparing apples to oranges, so it's really not a good comparison).

Additionally, the compressors duty cycle is a good thing to know while sizing a unit for a particular job.. Some need to have a rest period of a certain percentage of their operating time, to give the compressor time to cool down. You want this to happen to prevent breakdowns and to prolong the life of the compressor in your A/C unit. Usually, the duty cycle is expressed as a percentage of a certain time frame, often a 10 minute segment. So a duty cycle of 50% for a particular brand and model of A/C would mean that this particular unit could run steadily for 10 minutes, and then it must have a 10 minute rest period before it kicks in to cool again. Often it's the home owner that gets caught in the duty cycle trap, not knowing what the duty cycle of their unit is, and burning it out prematurely through too prolonged a usage. The point being that any money you might save in electricity by running a higher duty cycle unit might be negatively impacted if your unit fails in X years instead of Y.

I think the same could be said for a 200hp vs a 150hp. If all you're doing is cruising along at say 30 knots wouldn't the 200 be just loafing along at a lower rpm while the 150 would need to be running at a higher rpm just to maintain the same speed? I'd think that the 200 would be more fuel efficient under those conditions. (And really, when you're out in the ocean, you hardly ever get the nice flat seas that allow you to really let it all hang out. Most times it's 30-35 if you're lucky).