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Author Topic:   2 stroke or 4 stroke application
Jim Turnbull posted 04-26-2002 05:10 PM ET (US)   Profile for Jim Turnbull   Send Email to Jim Turnbull  
Which Mercury 40 application works best on a Classic 13 Sport?
The options are:
the 40 2 stroke, 2 cylinder
the 40 4 stroke, 3 cylinder

The 2 cylinder 2 stroke is about 50 pounds lighter and seems quicker out of the hole.
Aside from the fuel economy, is the 4 stroke 3 cylinder 40 Mercury going to provide the top end speed that the 2 cylinder, 2 stroke engine does.
Comments welcome...thanks.

PMUCCIOLO posted 04-26-2002 06:42 PM ET (US)     Profile for PMUCCIOLO    
Jim Turnbull,

I, on the 13, am a fan of the two stroke engine. The reasons are lighter weight, better hole shot, and less complication. I doubt that the 40HP 4-stroke will provide a better top end due to the weight differential. The midrange torque will be higher with the four stroke, and, trim aside, it may be able to maintain a plane at a lower speed with a heavier load.

I've had personal experience with both engines on 13's, and I'd prefer the two stroke engine. Others will have different opinions, and those are largely the result of different applications and expectations.

Good luck!


whalernut posted 04-28-2002 12:04 PM ET (US)     Profile for whalernut  Send Email to whalernut     
That 40 4-stroke will make the rear squatty and the bow high, I know a guy with a Honda 40 and it sits just ridiculously high in the front and very low in the back. Take the 2-stroker and give up the 50lbs. Or you could go to the 25h.p. 4-stroke, it would kind of even all of the weight issue out. Jack.
Dick posted 04-28-2002 01:50 PM ET (US)     Profile for Dick  Send Email to Dick     
True a 2 stroke is quicker out of the hole and a little lighter but after running a 4 stroke for the past few years I would never go back to a 2 stroke.
The 4 stroke is quieter, smoother, more economical to run and no stinky exhaust smell. I can give up a little hole shot for that.
GRMPer posted 04-29-2002 01:31 PM ET (US)     Profile for GRMPer  Send Email to GRMPer     
As a data point (don't know enough to make any recommendations)

My 2002 13 sport came with a 25 4-stroke (my choice).

With me, a copilot,gear and a dog (about 400 lbs. total.), the boat planes at 4600, peaks out at 6000 rpm (top end "allowed rpm").

With that load, it planes in a very short time (4 seconds?) and seems to have enough power to get out of trouble.

I added a doel fin, it reduced the minimum plane RPM to 4400, same top speed, less nose up when in-between.

With 3 people on board, with dog and gear...(600 lbs.) it will plane at 5k rpm and tops out at 5800 rpm.

With 4 people on board, it will not plane. (this, however, is probably 120 lbs. overloaded)

I think I can go to China on my 6.6 gallon tank. It gets very, very good mileage.


oldblue posted 04-29-2002 08:14 PM ET (US)     Profile for oldblue  Send Email to oldblue     
What speed are you getting at WOT with the 25?
GRMPer posted 04-30-2002 10:37 AM ET (US)     Profile for GRMPer  Send Email to GRMPer     
Beats the h*ll out of me. I was told 27mph by the dealer (big ol' grain of salt) fast enough for grins, not fast enough to have problems.

I do not have a gps to tell for sure.


pmc posted 04-30-2002 11:47 AM ET (US)     Profile for pmc  Send Email to pmc     
I was going thru the same things you were a month ago but decided to tryout the 4 stroke despite what I've read on this site and others. I've got a 1973 13' with a 2002 merc 40hp 4-stroke. It weighs in at 224lb w/ ptt. It sits in the water fine. The back end is a little heavy, the water line comes just below the self bailing drain hole on the transom. I moved the gas tank forward and try to keep most weight up front. The boat runs great! I don't know the speed for sure but I estimate it around 35-40 mph with only me in the boat. I have to hang on when I gun it, it gets on plane in no time flat. It sits in the water fine when I'm idleing down the waterway and planes out fine (w/ ptt), I never have to stretch to look over the bow. I've had up to 3 adults with coolers and gear and still had no trouble getting to plane and it still ran at a good speed. Plus the fuel economy is unbelievable. I'd recommend this motor to anyone with a 13'.
newboater posted 04-30-2002 05:43 PM ET (US)     Profile for newboater  Send Email to newboater     
I'm surprised to hear PR couldn't plane off with 4 aboard and a new 25. We've had 4 big people maybe 850 pounds total in our 13 and planed off without a problem. I'm running the original '75 Evinrude 40 too.

The 4 stroke gets my vote if you got the money to burn.

Dave S.

Bodie posted 05-05-2002 11:49 PM ET (US)     Profile for Bodie  Send Email to Bodie     
On my '79 13' sport, I replaced the original 40 HP Merc with an '00 30 HP Honda 4-stroke.

With one person, the top speed is 28-29 MPH. The new engine is dramatically quieter, cleaner, and more fuel efficient.

jbtaz posted 05-06-2002 08:35 PM ET (US)     Profile for jbtaz  Send Email to jbtaz     
I have a 2002 13 sport with a Merc 40 4 stroke EFI. Boats sits fine in the water, planes ion no time, has plenty of speed and is very efficient on gas. I love the engine and the boat!
pamlico posted 05-09-2002 07:54 PM ET (US)     Profile for pamlico  Send Email to pamlico     
lhg posted 05-09-2002 11:29 PM ET (US)     Profile for lhg    
Happened to visit my outboard dealer/service manager today, who sells both Mercury and Yamaha. He says that, for either brand, don't buy any 4-stroke outboard that is not EFI. He said that in the 30-60HP range, Mercury is the way to go, and better than the same HP carbed Yamahas. He doesn't recommend any of the Merc/Yamaha 75-100's, but likes both brands' 115 EFI's. In a year or so, he said Mercury will be coming out with 75-90 EFI's, (probably Yamaha too) and they are worth waiting for.

Evidently, for 4-stroke outboards, an EFI system makes a big difference in their overall performance characteristics. Honda is evidently working on converting their engines to EFI also.

crashq posted 05-10-2002 04:48 PM ET (US)     Profile for crashq  Send Email to crashq     
I have a friend that repowered his '62 13-footer with a 40-hp Mercury std shaft with trim& tilt (used to have a Johnson 25). He used a jackplate to account for the shaft length. He got the std shaft, because the short shaft did not come with trim and tilt.Of course, he used a jackplate to account for the shaft length.

The motor is great. It is powerful, fast and smooth. It does make the rear squat a bit, but does not affect the time to plane (at least not that I could tell). The boat will do 37-mph at full throttle(I measured over about a mile with my GPS). When taking corners at speed with one person, the rear end tends to slide a little. Nothing dramatic, but easily noticeable.

Personally, I would opt for a lighter setup ( i.e. short shaft, no trim&tilt, & no jack plate). I would maybe even go down one motor size. How many times do you really need to go more than 30mph. My Outrage can do 47mph, but I rarely exceed 30mph. In my opinion, a 25hp or a 30hp (if it is not a de-tuned 40hp)motor would be more than enough motor for a 13, and would also save you some cash.


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