4 Stroke or 2 Stroke?

[CatchumDeep]

I've about decided to buy a new motor. I've been told that the new models are designed for burning up to 10% ethanol. Since ethanol is probably not going away, I'm probably wise to buy a new motor than a used one.

I'm looking at a 2 Stroke Nissan DFI or 4 Stroke Mercury EFI. I'm wondering which would better handle the prolonged idling when pulling cranks? Also, which motor should give me better speed when running full throttle?


Any opinions?

[MSUAPM]

Good luck getting a majority answer on this topic!

My opinion is 4-stroke for prolonged idling and 2-stroke for that jump on the whole shot and top end. However, they say the 4-strokes have come a long way and the speed factor isn't as much of an issue as before.

[Wannabe...]

No matter what the majority says, here's the answer and the only one that counts - mine.

MSU is right. Plugs can get fouled on 2 strokes, plus run rougher at idle, not to mention cold starting. EFI 4 stroke is the way to go there. Now, all else being equal.......say a 40 HP 2 stroke will be lighter than a 4 stroke....depending on the HP and the make, might be a little, might be a bunch. That alone will mean the 2 stroke will win as far as top end goes due to pushing less weight. It'll also develop its HP quicker combined with the reduced weight will mean it'll climb out of the hole faster and with more authority.

2 stroke is capable of higher revs and is more foregiving to the shade tree mechanic. 4 stroke needs less annual maintenance, but the maint that is required under the cowl will most likely have to be done by a real mechanic.

4 stroke is the winner for me. Torch will say different, but then he hangs out with Satdoc, so he's totally discredited.

Wannabe...

[CatchumDeep]

Yeah, I'm leaning toward the 2 Stroke based on what I'm hearing and based on the weight. A 2-Stroke 40 weighs about 180 lbs and a 4-Stroke 40 weighs about 210 lbs and my old Evinrude 30 weighed 120. I'm a little bit afraid of the 210 lbs although my boat is rated for 40hp (but that was in 1992 when motors didn't weigh so much). I do troll cranks alot during the summer and often use my big motor instead of trolling motor when it is windy.

Do you think the 2-stroke will have a lot of trouble dealing with prolonged idling?

[Wannabe...]

Yes, yes I do. Torch doesn't (please refer to previous dismissal). 'Course, it's been done for years, long before anyone ever even dreamed of building a 4-stroke. If you're gonna go that route, make sure to buy the best fuel, run sta-bil/sea foam or the manufactures suggested fuel conditioner and decarb twice a year if you're gonna do a lot of it.

The problem is the buildup of the carbon deposits on the cylinder walls and tops of the cylinders due to the low operating temp and or extra oil at idle in the case of the auto-oilers. This leads to sticking rings, which you've had experience with.

Not that it can't be done, or hasn't been done, but I don't think an auto-oiling 2 stroke is your best bet there.

Wannabe...

[Wannabe...]

PS - have you thought about the direct injections - Like Nissan TLDIs or Etecs....don't think Opti makes a 40 but I know the other two do. Might split the differnce in the weigths and get EFI benefits for idling characteristics, plus computer controlled oiling.

Wannabe...

[CatchumDeep]

The Nissan TLDI 40hp is the one I'm looking at. The mechanic at their shop thinks that crankbait trolling would not be a problem due to the DFI control.

[Wannabe...]

As I've stated before, Torch is a gewber.

Never touched a Nissan and you couldn't prove it if I had, but they have a good reputation from what I hear. I'd still doctor the fuel religiously and decarb regularly according to the manual. Betcha it'd be a sweet mota.

I'm beginning to think Torch actually enjoys being pot-shotted and poo-dipped. He ain't said a word and this is the third smack up side the head I've given him.

Wannabe...

[jimmydee1]

Yeah, but while ya'll busy tryin to dip stick Torch, he's out catchin slabs. heeeheee He be thinkin he's got the last laugh.

[pstone]

I don't know all of the technical stuff WB has been talking about, but I can tell you I been pulling with my 50 2 stroke for a couple years with no problems. It might break down tommorrow, but so far so good.

One thing I would LOVE about the 4 stroke is a quieter idle....Listening to the 2 stroke all day sucks....