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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?

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

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.

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

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

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

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

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

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.

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.

silverking wrote: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.

I didn't say I paid full retail.