2018 242X E-Series Wake Super Slow When Turning

[UtahJetCap]

I’m new here and new to Yamaha and have been trying to find info about this here, but haven't yet. Looking for some insights. Just bought a 2018 242X E-series Wake boat and I like a lot of things about the boat. One thing I’m disappointed with is the boats inability to maintain speed when fully turned. I live in Utah and boat lakes between 3200-6500 ft so I put in the high altitude impellers, never was on the lake with the stock ones. When I turn hard either direction there is a dramatic inability for the boat to maintain speed. I can be cruising at 30 mph and turn hard to complete a 180 and the boat nearly comes off plane and I’ll slow down to about 17-18 mph by half way through the turn. Any thoughts or ideas? Is this typical of the Yamaha? I keep the boat at full throttle and the rpms seem to maintain but speed does not. Hoping to find a way to improve this aspect.

 

[Fozzy]

The trailer is not still hooked to it is it? I have a 242 LSE and it does fine at Jordanel. I ran mine with the regular impellers and it would not hit the rev limiter and topped out about 30 MPH. With the High altitude impellers it hits the rev limiters at 42MPH on glass. 30 would be top speed on normal Utah water. The boat is a pig to turn if you are new to jet boats. Turning aggressively will cause the jet pumps to cavitate. So when you say you come off plane are the engine RPM's still up? If they are, you are pulling the inlets out of the water or making the water to turbulent to enter the jet pumps. We boat Lake Mead and I still leave the High Altitude impellers in since we surf, board, tube and have a boat full of people. I can cavitate the jets at will at the lower elevation. I do not have ballast in my LSE, I am assuming you're not turning at 30 with all your bags full. That would have a negative effect on performance as well.

 

[mrmeaniemeateaterman]

Welcome aboard. I'm guessing this is not a Yamaha problem, this is physics. And you will never beat physics, it always wins. Acceleration by physics definitions is a change in velocity or direction or both. While you are going straight at 30mph you are not accelerating because your velocity and direction are constant. Once you start to turn you have changed your direction so your velocity must increase in proportion to keep your "speed" the same, otherwise you will decelerate. The sharper the turn the more throttle/fuel you need to maintain your "speed". High altitude and the added drag of the water is not helping all this and thus you lose a lot of speed, especially doing a 180 degree turn. Keep in mind these boats will turn a lot sharper than most boats anyway. The simple answer is don't turn so sharp so that you stay on plane and keep your nozzles in the water like Fozzy said. If you did a 180 and kept going 30mph the entire time you better have that red kill lanyard strapped to your pants because you're coming out of that boat.
https://www.khanacademy.org/science...on-tutoria/a/what-is-centripetal-acceleration

 

[UtahJetCap]

The trailer is not still hooked to it is it? I have a 242 LSE and it does fine at Jordanel. I ran mine with the regular impellers and it would not hit the rev limiter and topped out about 30 MPH. With the High altitude impellers it hits the rev limiters at 42MPH on glass. 30 would be top speed on normal Utah water. The boat is a pig to turn if you are new to jet boats. Turning aggressively will cause the jet pumps to cavitate. So when you say you come off plane are the engine RPM's still up? If they are, you are pulling the inlets out of the water or making the water to turbulent to enter the jet pumps. We boat Lake Mead and I still leave the High Altitude impellers in since we surf, board, tube and have a boat full of people. I can cavitate the jets at will at the lower elevation. I do not have ballast in my LSE, I am assuming you're not turning at 30 with all your bags full. That would have a negative effect on performance as well.

Haha... Yes, we left the trailer on land What do I need to watch for/listen for with regards to jet pump cavitation? With my previous outboards I would hear the engine noise/pitch change when the prop would cavitate. I didn't notice any engine noise or pitch changes leading me to thing the jet pumps were cavitating. Also, ballasts were empty... only filled while surfing.

 

[Fozzy]

Maybe you need to explain how hard you are trying to turn. I can turn at 30 and tip the inside of my boat where you can almost touch the water over the rail. I could turn tighter and and end up tipping the boat the other way and take the chance as said above of throwing everyone out of the boat. In this situation you would come off of plain and there is no way you wouldn't lift the back of the boat out of the water and cause the pumps to suck air. I have done it. It is hard to tell if you are sucking air at high rpms as the boat sounds like there is a bunch of bees kicking someones ass under the hood. But as you turn watch the rpm's ,if you are slowing to 17 mph and still in the upper range you are sucking air or have a vacuum in your pump. Remember a Yamaha jet boats nozzles are out of the water at plain speeds. The only thing in the water is the intake grates. When you come off plane the nozzles re enter the water and have more work to do to move the boat forward. A regular boat the prop is always in the water. If I get it to work here is a cool video Jet Boat Pilot did showing the boat on plane and how far the nozzles are out of the water.

 

[chrisinslc]

I’m new here and new to Yamaha and have been trying to find info about this here, but haven't yet. Looking for some insights. Just bought a 2018 242X E-series Wake boat and I like a lot of things about the boat. One thing I’m disappointed with is the boats inability to maintain speed when fully turned. I live in Utah and boat lakes between 3200-6500 ft so I put in the high altitude impellers, never was on the lake with the stock ones. When I turn hard either direction there is a dramatic inability for the boat to maintain speed. I can be cruising at 30 mph and turn hard to complete a 180 and the boat nearly comes off plane and I’ll slow down to about 17-18 mph by half way through the turn. Any thoughts or ideas? Is this typical of the Yamaha? I keep the boat at full throttle and the rpms seem to maintain but speed does not. Hoping to find a way to improve this aspect.

Which dealer did you work with when you got the high altitude impellers?

 

[iamcalled]

Maybe you need to explain how hard you are trying to turn. I can turn at 30 and tip the inside of my boat where you can almost touch the water over the rail. I could turn tighter and and end up tipping the boat the other way and take the chance as said above of throwing everyone out of the boat. In this situation you would come off of plain and there is no way you wouldn't lift the back of the boat out of the water and cause the pumps to suck air. I have done it. It is hard to tell if you are sucking air at high rpms as the boat sounds like there is a bunch of bees kicking someones ass under the hood. But as you turn watch the rpm's ,if you are slowing to 17 mph and still in the upper range you are sucking air or have a vacuum in your pump. Remember a Yamaha jet boats nozzles are out of the water at plain speeds. The only thing in the water is the intake grates. When you come off plane the nozzles re enter the water and have more work to do to move the boat forward. A regular boat the prop is always in the water. If I get it to work here is a cool video Jet Boat Pilot did showing the boat on plane and how far the nozzles are out of the water.

That video is cool. Thanks for sharing.

 

[J-RAD]

Hi @UtahJetCap, I'm a Utah boater as well. We frequent Utah Lake, Yuba, Starvation, & Lake Powell. I have a 2016 AR240 that I purchased new from South Valley Motorsports. I've been running stock impellers since new. I've been tempted many times to experiment with impellers and pitching but, I've been to busy spending money on everything else. With a full tank and loaded I manage to hit 41-43.

Here's what I know and have learned. Jet boats are great and the 242x is the upper crust. That said, jet boats can also be fickle creatures, small issues can have an impact. There are a lot of factors that play into performance and make them perform differently than an i/o.

Altitude - is a major factor in engine performance and can restrict the rev limit.

Weight - the 242X E-Series if fairly light weight when compared to other similar size boats but, it is the heaviest of the 24' models.

Drag - the size of the hull anything dragging under the water has an impact.

Pump efficiency - impeller pitch, blade overlap, sealing, damage.

With the major factors identified a lot of them can be addressed at the pumps. Changing the impellers and pitch can help gain back RPMs lost at altitude, changing pitch and overlap can increase or decrease the likelihood of cavitation. A heavier boat, especially those with ballast, will benefit on the low end from a impeller that has more traction. While at the same time an impeller with a lot of traction might be less efficient at higher speed... so it's kind of a game of finding a happy medium.

I'm not sure where you purchased your boat but according to @Williamsone46 in one of his threads last spring mentioned that South Valley was putting the 6WC impellers from the 190s on your model boat to improve low end and also reported a 700 rpm gain.

There are other things that can be done to improve the efficiency and decrease cavitation issues. Those include adding after market cones and the even more hands on tactic of porting and smoothing your pump intake to cut down on turbulence.

When it comes to turning a jet vs an I/O the mechanism is entirely different. For the later, the entire drive moves and redirects the thrust. On a jet, only the nozzles move to redirect the thrust. In my mind it's a bit like kinking a garden hose, it will rob some of the thrust as it redirects it while simultaneously changing the loads on the impellers, which could lead to cavitation. Adding @Cobra Jet Steering LLC fins can greatly improve handling while at speed.

Edit: pre 2015 model year 24ft boats were not equip with the articulating keel hold and were probably a lot more fun to throw into a turn. However the handling was probably a little less predictable for a novice boater.

 

[Cobra Jet Steering LLC]

Put some super magnum A K steering with mega fang plus on the boat first and you will be able to do turns at high speed that will scare you just ask @swatski not to mention turns OFF POWER

The keel down the center of your boat acts like a fixed rudder making the boat want to go straight the faster you go the more it resists turning in this picture originally posted by someone on this board I believe you get a view of the factory rudder partly out of the water at speed. This gives you reduced steering influence to overcome the keel. in high speed turning. The super magnum A K steering gives you 2 more rudder with more exposure to the water under the hull and the leverage of having them off to the side of the keel. Then the mega fang plus fins also add to the influence by leading the back of the boat so it turns and it does it very quickly with very little speed bleed off. turn and rapidly decelerate at the same time, No problem ! Even do S turns off power like the video shows.

 

[Jgorm]

Are you at full throttle during the turn? You need to add substantial throttle to maintain turning speed in any boat. Just checking there basics first.