90 HP Yamaha 2 stoke vs 4

[FTReelty]

Have a 2006 90 hp 2 stroke on a 1720 Key West. Have a chance to "upgrade" to a newer 90 4 Stroke. Am I gonna notice a big difference initial lift off? I know its more fuel efficient and quieter. Been pleased with current motor-has overheated a few times, but had it checked out and good to go. Have just heard the 4 stroke might not get up off plain as good as 2?

[Redbelly]

If you prop it correctly it can lift off, as good as the 2 stroke.......?

[silverking]

Depends on the four-stroke. Newer models have much better initial acceleration but still won't match a 2-stroke as far as lower end torque. Weight is another factor too. Check the difference between the two engines. The heavier four-stroke may keep the stern lower in the water, which could affect self-bailing, how it sits at rest and center of gravity.

[Steve Stinson]

Silverking is correct. The lack of torque and also excessive weight were problems back when 4 strokes first came out, but those issues have been resolved over time. I have a 2013 90 hp Yamaha 4 stroke on a 2072 Sea Ark. It has no issues getting on plane even with 3 people on board, and the gas mileage is great.

You are welcome to come drive it if you want to see the performance for yourself before making your motor swap.

- Steve Stinson

[FTReelty]

That's all I needed to hear. Thanks for good advice!-and generous offer Steve!

[turtlecat]

Just out of curiosity, what pitch prop do you run on your Sea Ark Steve?

[Steve Stinson]

I am not sure, but I will check it for you when I get home. I bought the boat with very low hours on it. It had two aluminum props that both looked like new. Now they both look well -worn and I will likely have to buy a new one when I turn it in for the annual service in December. I may end up going with a stainless at that point. The top-end rpms are right where they should be for that motor, and the top speed is about 36 - 39 mph. My boat has the rear floatation pods on the transom, so trimming the motor up at speed does not lift the hull out of the water much.

- Steve Stinson

[Steve Stinson]

I checked my prop last night. It is stock Yamaha aluminum prop. 13 X 19

[turtlecat]

Thx Steve! Sounds like your boat is dialed in. Never been on a boat w the extra float pods in the rear. I would think that they help w planing off. As for the 4stroke question, I'll never own another 2stroke! My Dad has a G3 17.5 w a 60 Yamaha 4stroke. It will jump on plane in a heartbeat and push the boat moderately loaded at WOT about 32mph. GREAT on gas! Quiet as a whisper. I've tried to crank it numerous times to the sound of a grinding starter. I've made it a habit now to glance back real quick to see if the motor is peeing before turning the key.

[silverking]

Started out with Mercury years ago before switching to Evinrude, mainly for the local service (Shields), hole shot and the weight savings on my flats boats I used for guiding. Went with an Evinrude E-TEC on the Micro, again for weight, but when I sold it to have the Mosquito built, I switched back. Mercury wanted me running their products so I bought a 60-hp EFI four-stroke and couldn't be happier. It's not much heavier than the comparable E-TEC, has a great hole shot with good power throughout the range. Super quiet and sips gas.

Evinrude, the Mercury Optimax and a few models of Tohatsu are about the only two-strokes left. The EPA is forcing them to eventually phase out, even though the emissions on the E-TECs still meet and exceed the standards.

Since the Mosquito is likely my last boat and the four-strokes last forever, I'm set now with black four-stroke power.

[reelbad]

Started out with Mercury years ago before switching to Evinrude, mainly for the local service (Shields), hole shot and the weight savings on my flats boats I used for guiding. Went with an Evinrude E-TEC on the Micro, again for weight, but when I sold it to have the Mosquito built, I switched back. Mercury wanted me running their products so I bought a 60-hp EFI four-stroke and couldn't be happier. It's not much heavier than the comparable E-TEC, has a great hole shot with good power throughout the range. Super quiet and sips gas.

Evinrude, the Mercury Optimax and a few models of Tohatsu are about the only two-strokes left. The EPA is forcing them to eventually phase out, even though the emissions on the E-TECs still meet and exceed the standards.

Since the Mosquito is likely my last boat and the four-strokes last forever, I'm set now with black four-stroke power.

If Merc wanted me to run their products I think I would let them buy it.

[silverking]

I didn't say I paid full retail.