2017 Yamaha AR195 - Working through issues at elevation & addressing performance

[ScottS]

Hi all,

I'm new to the boating world and I just wanted to share some of my growing pains in learning about and dialing in our boat. We are located in SLC, UT and we boat at elevations typically between 5,000-6,200 feet ASL. Strawberry Reservoir is nearby at 7600' ASL but as I will outline below, I think it is off the table for watersports.

We bought our 2017 Yamaha AR195 (w/ 5.8 hours) early this spring and I immediately went out and bought a Slalom ski (Radar Union) thinking I can finally ski year-round. In retrospect, I probably should have started on two skis. But I have persevered and I am up and skiing and loving it. However, our boat struggles to get me up on the ski at any of the local lakes - I am 6'1" and 190lbs. I haven't been able to get either of my 200-220 lbs brothers up on a slalom ski as of yet. We are able to get people up on the wakeboard with little effort. I am confident that our AR195 is capable of the performance necessary to be a full use watersport craft and I want to dial it in over this season. Hopefully, with a little input from helpful members of the forum, I can best direct my efforts.

The first thing I tackled was to baseline the boat - oil change, grease zerk fittings, and new spark plugs gapped appropriately. We didn't feel much if any improvement from this, but it settled the stress I was feeling with not knowing the history of the boat. On that note, South Valley Motorsports where the boat was purchased was acquired by MotoUnited in Draper and they appear to have lost the service records for the boat. So that continues to be frustrating.

I then installed the Lucky 13 cone after reading some helpful threads from @swatski and @Speedling. With the Lucky 13 cone, holeshot seems slightly improved, but it wasn't the holy grail I was hoping for. If anyone has any recommendations for dialing in the cone at elevation, I would appreciate the advice. I am currently running the cone with all of the spacers installed as that is what I read worked best for others at my elevation. See the below helpful threads from @swatski and @Speedling respectively
https://jetboaters.net/threads/lucky-13-adjustable-pump-cone.22960/page-2

https://jetboaters.net/threads/anyone-tried-the-lucky-13-perfomance-adjustable-pump-cone-in-a-boat.7967/page-3

• Purchased via Jerry (the discount in the link was honored for my purchase in June 2020): https://jetboaters.net/threads/lucky-13-adjustable-pump-cone.22960/

My next assumption is that I need a properly pitched impeller or to have Yamaha repitch my stock impeller. As I use the boat every weekend, I am pretty much unwilling to send the impeller to Yamaha. Also, as we have no service records for the boat - I don't even know if I already have a properly pitched impeller. Barring anyone being able to inform me of a technique for determining the impeller pitch, I am thinking I need to source a new one. Further digging through the forum has led me to impros.com as a source for the appropriate impeller. So I plan to give them a call this week.

Other Issues I am planning to address in the future or I am trying to work my through to understanding:

1. Heat Sinking of the intercooler - After a pull, there is a lot of steam coming from under the transom. If we go right back into another launch I can see the steam billowing up from behind the boat. I believe this is normal for our boats as the intercooler becomes overloaded and limits the performance of the boat. I typically address this by running the boat at no-wake speeds for a few minutes between people taking turns at watersports. I haven't been able to find a way to address this with a mechanical fix, as most people seem to be upgrading their SHO units to the same intercooler that is on my SVHO unit. So for now, it appears that running the boat at low demand for a short while or letting it rest for a bit between sets is the best action for now.
2. Low-Speed Maneuverability - Low on my scale of issues as I feel I can usually get the boat where it needs to be with a helping "hand" or two from my passengers. These 19' boats are pretty easy to manhandle when necessary. However, if and when we decide to tackle this issue, it appears that JetBoatPilot or CobraJetSteering are the go-to solutions. Jet Pilot Offers the Thrust Vector packages for low-speed steering enhancement and the Lateral Thrusters to improve reverse steering:
   1. Thrust Vector Review (on a 2018 Yamaha 242X): Product Review: JetBoatPilot's Thrust Vector XV - Steering You Straight. — Expedition Recreation
   2. Lateral Thrusters Review (on a 2018 Yamaha 242X): JetBoatPilot’s Lateral Thrusters: An Unfortunate Necessity — Expedition Recreation
   3. Cobra Jet Manufacturers Link: CJS VIPER Steering System
3. Effects of elevation on RPM: I touch on this a little below on hole-shot/seating arrangements, but I think this is more of an elevation issue. I read over a table on Boattest.com showing 7540 RPm being tested. I have also read about people at sea level hitting the REV limiter. Long story short, I don't think I have seen our boat hit past about 6400 RPM on a lake at 5000' ASL. Up at 6000' ASL, I was lucky to hit 6000 RPM. I am thinking that this is typical of the 1.8L SVHO engine. However, I have also read that our supercharger combined with EFI should "largely" negate the effects of elevation on our motors. I am hoping that a properly pitched impeller is the key to regaining some of these "lost' RPM and the associated performance.
   1. Boattest.com specs for the 2019 AR195 - I am making the assumption that having the same engine should warrant similar specs: Yamaha AR195 (2019-) | BoatTEST
   2. Nice Resource for Rocky Mountain based Dealer on elevation and engine performance: Boating in the Rocky Mountains Robertson's Marine Salt Lake City, UT (801) 534-1111
4. Where to put passengers for best Hole-Shot performance: I have played around with the best seating positions for passengers when trying to get up on a slalom ski. Unfortunately, as I seem to be on a different lake at a different elevation each weekend, I haven't settled on the "right" solution yet. However, typically we have three in the boat and one in the water when skiing. I feel we get the best performance having one person in the "pilot" seat, the next biggest person opposite them in the passenger seat, and the last person sits in the front with the center cushion in place facing to the rear. Having people upfront when underway or trying to pull someone up seems to be too much resistance for good performance. Even when not towing, having two full adults upfront on a lake at 6000' ASL limits us to 6000 RPM and about 32 MPH.
5. Spark Plug Gap - Specs call for 0.031-0.035 in. Is there a benefit to leaning narrower (0.031 in) or thicker (0.035 in) at elevation?
6. Density Altitude - As density altitude seems to typically increase our "functional" altitude, is this something worth taking into account when deciding on an impeller? I know I am starting to get into the weeds here, but I find it fascinating and welcome any insight. Thinking a discussion with my brother and father - both rotary-wing and fixed-wing aviators - may be useful for better understanding the impacts on performance from density altitude.
   1. Density Altitude Calculator: Density Altitude Calculator - English/Metric
   2. Forum Post that got me looking into this: https://jetboaters.net/threads/i-cant-drive-55.26763/#post-445879

If you have made it this far I hope that this helps others in a similar situation. If you have any recommendations, questions, or feedback, please reach out and I will do my best to address them. Hopefully, some of our gurus out there can provide some more insight in addressing my issues. If I failed to touch on anything that you feel may be pertinent to getting the best performance out of our boats, please chime in. Thanks in advance, don't be surprised if I don't respond after about 3 PM on Fridays as I'll likely be behind my boat or in it.

EDIT: @sysinu shared a great thread with me that tackles some of my issues. I had read it earlier but couldn't find it again for some reason. It is the thread that got me interested in Density Altitude. See below, and I'll post some of the useful nuggets below as well.
Link:https://jetboaters.net/threads/boating-at-elevation-whats-considered-high-elevation.21098/page-2

"Useful Nuggets" from @sysinu - "Utah" is synonymous with "Elevation"
If you are boating in Utah, you need 4500' altitude pitched screws.
If you are boating in Utah, you should really consider doing a ribbon delete and replace it with a riva spacer.
If you are boating in Utah, you should really consider doing the K&N air filter replacement.

If you're at altitude and not getting over 7000 RPM on each engine, you have a problem that needs to be fixed. If you've done those 3 things that I mentioned and you still have an issue, then take your boat to the dealer because it could be a ton of issues (ranging from improperly gapped spark plugs, bad spark plugs, wear issues in your jet pump, water flow issues, problems with your impeller, etc). But of those 3 things that I mentioned, 2 of them are all things that just about anyone that is handy can do, they are low cost. The third item, your dealer will do (unless it was caused by damage to the impeller) for free as a warranty repair.

If you're not boating in Utah, but are at high altitude, then I would say the same things apply except for the pitch angle of the impeller. This will depend on altitude. It's a combination of the mods that you would do to get the best performance. I boat at 6,500' altitude with 4500' altitude pitched screws, ribbon delete and filter replacement and my performance is great. When I take my boat to Lake Powell (3500' altitude), I either need to replace my impellers with 3500' altitude screws OR, I keep my 4500' screws on and then just take it a hair easier on my hole shot (I blow it out with that combination).

 

[2kwik4u]

I don't have a 195, nor do I boat at elevation. Take my comments with the appropriate grain of salt they need since I don't have "direct" experience with this setup. I am a gearhead by nature though, and have an engineering degree to back me up.......SO....

You need to get a new impeller. You should see 7.4k rpm or more. At least. You're not spinning that motor enough to get full thrust from it. That is due to elevation. Not a hard fix, but since you're using it so much, you'll want that replacement. The people at Impros can help with that. You have a 160mm pump if they ask, but I doubt they will. More RPM on the engine means more thrust out the back of the boat, and more power transfer to the water. It's the same premise as "gearing down" in a vehicle. You have reduced engine torque in this scenario (because of the elevation), so you need to "regear" in order to allow the engine to spin up higher in the rev range. Keep in mind, Power is just Torque times revs. So you get no power without BOTH torque and revs. Torque is governed by airflow, HP follows as you rev higher.

The supercharger will NOT negate the losses at altitude. The supercharger spins at a given rate relative to RPM. More revs on engine = more revs on supercharger. The boost created is just the resistance to flow of air through in the intake manifold. If the air is thinner, boost goes down. A TURBO charger however, does not tie the air impeller speed to the engine rpm, so it is able to move more air at altitude. This is a common misconception about how the devices work. Just know that you can't pump any more air than what is available with a supercharger, because it is tied to engine rpm. i can go into more detail about how the control systems work if you like, but the gist is that turbos are controlled with boost pressure, and superchargers are controlled with engine rpm.

The steam coming from the back isn't from the intercooler, it's from the exhaust. It's normal and not going to hurt anything. Even my little 190 does the same thing if we've been running it hard for awhile tubing/etc. If you're concerned, running it in no wake mode between pulls is a great idea. This helps move more water through the engine and intercooler to keep temps down. Also you can run the blower to exchange the hot air in the bilge with cooler air from outside. Running the blower has helped some of the N/A guys keep from vaporlocking the engines at elevated temperatures. Doesn't hurt anything, it's just a nuisance.

 

[ScottS]

@2kwik4u Thanks for the detailed response.

I'm actually relieved that it appears readily apparent that I need a new impeller. I hate throwing parts at a problem. I get the analogy of gearing down- I just went through it with my 60 Series Landcruiser after putting a lift and larger tires on. I hope the results of a new impeller are as readily evident.

I see what you are saying about the Supercharger, I guess I just thought that it would be a "self-reinforcing" cycle. So spool up would be delayed against performance at Sea Level, but I would still get there eventually. But I never thought about the actual impact of air density in the manifold.

As for the steam being related to the intercooler, thanks for being more precise than me. I think I was conflating heat issues being tied to intercooler size with the source of the steam. Agreed, I had no intention of giving people the idea that the intercoolers are boiling steam out of our boats.

Once again, thanks for weighing in and providing some direction and advice!

 

[ScottS]

Ordered an impeller spec'd for 5500' from impros.com. Hope to have it in hand by 07/10/2020. I don't know if I will be able to get it in before we use the boat this weekend, but I'll have it in before the weekend of 07/17-19/2020 if humanly possible. Having never changed an impeller, this could be more than I bargained for. Glen at Impros did have me purchase the impeller shaft tool for about 20 bucks. So keep in mind that you may need that to do the swap.

Searching for a good thread showing how to do the impeller swap on the SVHO equipped units now.

 

[ScottS]

Searching for a good thread showing how to do the impeller swap on the SVHO equipped units now.

Well, fancy that, the thread I needed was in the FAQ!

looks like I’ll finally have to buy that vice...

https://jetboaters.net/threads/how-to-remove-the-impellers-for-dummies.3811/

 

[sikm3]

If you want more power, you'll need to increase boost since you're at higher elevation as previously mentioned. The only way to do that is with a new impeller like this one https://rivaracing.com/i-20756255-riva-yamaha-svho-supercharger-impeller-17-psi.html
Best to talk to Riva as they have lots of experience upgrading jet skis at elevation.

 

[ScottS]

@sikm3 thanks for linking that impeller. I haven’t seen that even mentioned anywhere else. I just ordered an impros.com elevation adjusted impeller and I’m excited to see where that takes me.
If things still aren’t where I want them, it looks like looking into a Riva setup may be my next step. Thanks again for the lead!

 

[jgourlie]

@sikm3 thanks for linking that impeller. I haven’t seen that even mentioned anywhere else. I just ordered an impros.com elevation adjusted impeller and I’m excited to see where that takes me.
If things still aren’t where I want them, it looks like looking into a Riva setup may be my next step. Thanks again for the lead!

I am super curious as to how this pans out. I am at 3500 feet here in Alberta and wouldn’t mind a few more rpm myself.

 

[ScottS]

@jgourlie I’ll post the impacts of the new impeller as a follow up. I just got shipping info. Hoping it arrives by this Friday. But I still don’t have a delivery date, so it’s just fingers crossed for now.

 

[jgourlie]

I was just working on my throttle drop issue with my throttle control last night and I discovered that I had an 1/8 of an inch remaining in my throttle stop. I have high hopes that was a couple hundred rpm of the throttle not opening all the way.
fingers crossed

 

[Calphor]

I had the same problem with my 190 when we first purchased. I worked with Dick’s in Clearfield and they had a shop in Colorado repitch an impeller. The new impeller had me hitting 7700 at Willard Bay. The ribbon delete and Riva filter element pushed it to the rev limiter. I haven’t been up to Strawberry, but East Canyon drops my rpms to 7500. Just installed an L13 this year, but after 8 years my impeller and wear ring need a refresh.

Enjoy the extra speed!

 

[ScottS]

Thanks for the info @Calphor

I hit Willard (4,200' ASL) early this year and was on the water when air temps were in the 60's-70's and water temp was around 64 degrees. Our AR195 pulled pretty strong with the stock impeller in those conditions. I chalk most of that up to having a supercharger though. I think a large part of the performance issue I am hoping to solve is tied to the Summer heat having finally arrived at the high mountain lakes (5,000'+ ASL - Deer Creek, Jordanelle, Rock Port, East Canyon, Echo). As discussed above, and highlighted by you, a repitched or appropriately pitched impeller should help me recover the top end of my RPM range and the most benefits from the Supercharger. I may try Strawberry later in the season with the new impeller once temps start to cool off in the mornings and evenings.

Looks like my impeller isn't due to arrive until Saturday now, so I may not get a chance to test it out until Sunday. Still trying to figure out the weekend plans so I can make the change and post a review of impacts.

 

[ScottS]

Well, In reviewing my invoice, I noticed that impros sent out the wrong impeller. Talked with Glen and he is going to send out the correct one with a return label. I guess we will see how we do this weekend staying on the stock impeller.

 

[Calphor]

Just as a follow up, I was at East Canyon Friday and max rpms were between 7300-7400 rather than the 7500 I had remembered.

 

[ScottS]

Spent the weekend at Echo Reservoir (5560’ ASL) and the boat continues to struggle pulling me up on the slalom ski. Wakeboards were pretty easy going. The tube wasn’t very fun, just couldn’t maintain or recover speed well enough to really get any action. Still on the stock impeller. The correct new one should arrive tomorrow. Really hoping this helps.

I’m curious if the Lucky 13 has actually hurt performance since the boat won’t get above 6000 RPM. If I’m unhappy with performance post new impeller install, I’m going to start playing with the rings on the Lucky 13 and see if removing them improves performance. But I want to leave it alone so I’m not messing with anything at the same time as the impeller.

On a cool side note, saw a good number of Yamahas up there. 210’s, 212x’s, and a few other twin engine boats. I think we even saw a 240.

 

[Calphor]

@ScottS, have you looked into the ribbon delete and air filter replacement? Those two items are worth doing while boating in Utah, especially on the supercharged versions. Flow restrictions are the bane of forced induction systems. It won’t solve the whole problem, but they will free up rpms on the top end once you get the new impeller installed. Besides, it takes less than an hour to do both items.

 

[ScottS]

@Calphor, I have looked into them. Browsing through the forum has given me mixed messages on the benefits of the ribbon delete on forced induction engines. I would want to stay Coast Guard compliant so I would want to install the correct air filter if I do the ribbon delete. If you have first-hand experience, or can tag someone who has done the delete and air filter at elevation, I would love to hear of the experience and effects. If the change of impeller and the Lucky 13 still leave the boat feeling sluggish then that will likely be my next step.

 

[Calphor]

I have done the ribbon delete and air filter. It was an easy upgrade. To be honest, with my car background, once I found out about the ribbon delete, my own compulsions almost forced me to change it out. I just can’t understand why you would put such a restriction in the intake of any engine. If I had a forced induction system, I would have been even more compelled to remove it. (For clarity, I raced (AutoX and Drag) forced induction cars for a number of years) My need to be Coast Guard compliant had me install the appropriate filter element. As for performance, I gained 100-200 rpm on the top end. Noticeable, but not earth shaking.

 

[ScottS]

Well, the new impeller is installed. It was pretty straight forward. Had to buy a set of larger wrenches to do it. I thought I needed a 36mm for the Solas impeller wrench tool to tighten the new impeller, but couldn’t find one local that was decent quality, so I used an adjustable crescent wrench. I hope I got it tight enough, I had a hard time getting leverage. To remove the OEM one was a tough nut to crack. Ended up using the box end of a 1 1/8” combo wrench As it wasn’t a very long tool I had my fiancé hold the housing while I laid down and braced my feet against the bottom of my workbench and pulled down on it. I about burst a blood vessel trying to muscle it off alone before asking her to hold the housing. I’m not hulk, but I’m in pretty good shape... what I’m getting at is, don’t waste your time trying to do this solo unless you rig up a way to hold the housing. Without a vice, I’m not sure how you would hold the end of the drive shaft. Maybe I could have ratchet strapped it in place. Didn’t think about that until this write up.

I dressed up the threads with Yamalube grease and got everything snugged up. Taking out the impeller and driveshaft and putting them back in wasn’t really any more difficult than installing the Lucky 13 cone. Just two more bolts. Interestingly, I didn’t even need to break the housing free with a pry bar or screwdriver. Just gave it a good shake and it popped off. But maybe chalk that up to our boat only having about 50 hours. A reminder here not to lose the little studs that help set each section of the housing (single housing on 2019+ I believe)

I really hope this results in significant improvement in performance, it’ll really increase my enjoyment with our boat. It’s just turning into a slug in this heat. Fingers crossed.

On another side note, when I started it up to test it and make sure the thing didn’t fly apart due to some ineptitude on my part, it ran extremely quite. I don’t remember our boat being loud other than engine/exhaust note, but it just seemed to hum more quietly and have less vibration. I didn’t note any issues with the stock impeller, so maybe I’m imagining it.

I’ll follow up after a water test this weekend.

 

[ScottS]

Finally made it up today (Sunday). Ended up at Rockport (6038’ ASL) So not apples to apples. But overall, I’m quite happy with the Impros elevation adjusted impeller. I’ll give a more comprehensive response later. But, all in all, happy with the investment. Haven’t run all of my assessments yet, as I’ve been behind the boat all morning, but I saw north of 7200 RPM and the bot definitely is pulling stronger. Super happy.