Another AR190 top speed thread, fully loaded, only 27 mph?

[FSH 210 Sport]

View attachment 186488

Your RPM’s don‘t look too bad, you might be missing 150 rpms?

When I was doing my research on impellers for high altitude I looked at the dual impeller design… they are mainly for towing people, they have excellent bite in the water, but the sacrifice is in top speed.

How has it been over the last year?

 

[dvrice]

The newest hulls are down a bit on speed. They're a shade heavier, and have slightly more planing surface. I think high 30's is the right target for you. I would expect slightly more than 32 though. Check the revs for certain. You should be up around 7,600 rpm or so. Does it cavitate on launch at all? Ever feel like it's "losing traction" throughout the rev range? When was the last oil change and last spark plug change? How does the air filter look? Clean or dirty? Oil level in spec? Overfilled? Underfilled? What altitude are you running at?

The single engine non-supercharged boats are sensitive to loading in the bow killing speed. The second easiest way to lose speed is to operate at elevation.

I checked my '17 AR190 this weekend and WOT with 2 adults, 2 kids and gear was right at 39mph (GPS speed) with revs at 7,550. That was light chop, bimini deployed, and the boys in the bow (they're getting heavy now!). Mine's lost a step or two along the way. I'm guessing the hull is dirty, and I likely have some wear on the impeller/wear ring now that is giving my some slippage. This is me 7th season with the boat, and I've never pulled the impeller on it. Only mods are a ribbon delete, sealed intake tunnel, and L13 cone. Used to hookup like a scared cat on carpet, starting to get a little cavitation on launch, so I'm suspecting wear is finally appearing. 225hrs on it with 99% of those being debris free fresh water. Couple hours in salt water, and maybe 2-3 clogged pumps over the years. I was at ~675ft ASL on these runs.

I purchased the 2021 SX190 a couple months ago and it had not been out this season since dealer winterization. I have taken it out twice so far. The boat only has 80 hrs on it. I did change the oil with Yamalube branded oil change kit. I have not changed the spark plugs. Should I consider replacing the spark plugs after 80 hrs?

This is my first jet boat but I previously had a Yamaha VX waverunner. There does seem to be a bit of cavitation or less "grab" with the boat compared to what I was used to with a waverunner. That may just be the difference is weight/size of a boat compared to a PWC.

If you think spark plugs are worth a shot that may be something easy and cheap to try before I even take it out next time.

Next time out I will look at speedometer, check it versus phone GPS speed, and look at RPMs

 

[2kwik4u]

I purchased the 2021 SX190 a couple months ago and it had not been out this season since dealer winterization. I have taken it out twice so far. The boat only has 80 hrs on it. I did change the oil with Yamalube branded oil change kit. I have not changed the spark plugs. Should I consider replacing the spark plugs after 80 hrs?

This is my first jet boat but I previously had a Yamaha VX waverunner. There does seem to be a bit of cavitation or less "grab" with the boat compared to what I was used to with a waverunner. That may just be the difference is weight/size of a boat compared to a PWC.

If you think spark plugs are worth a shot that may be something easy and cheap to try before I even take it out next time.

Next time out I will look at speedometer, check it versus phone GPS speed, and look at RPMs

At this point don't change anything.

Get us a speed vs rpm reading at a few spots. WOT, 20mph and 25mph. We can infer slippage from there. Also, what elevation are you boating at?

Really the WOT GPS vs RPM reading is the big one. If you're not getting full revs then you have a power creation issue (plugs, oil, filter, altitude, etc). If you're getting full revs, but not full speed, then you have a power delivery issue (cavitation caused by pump sealing, wear ring damage, impeller damage, nozzle tuning, etc).

 

[dvrice]

At this point don't change anything.

Get us a speed vs rpm reading at a few spots. WOT, 20mph and 25mph. We can infer slippage from there. Also, what elevation are you boating at?

Really the WOT GPS vs RPM reading is the big one. If you're not getting full revs then you have a power creation issue (plugs, oil, filter, altitude, etc). If you're getting full revs, but not full speed, then you have a power delivery issue (cavitation caused by pump sealing, wear ring damage, impeller damage, nozzle tuning, etc).

I took it out yesterday. Three adults with a combined weight of 400 lbs. Gas tank was at 70%. Water was slightly choppy. It was very consistent wide wide open throttle to top out at 32 mph at 7,300 rpm. This is a 2021 SX190 with fresh oil change this season but did not change plugs. Any thoughts or ideas?

 

[dvrice]

Sorry forgot, my lake elevation is 630 ft

 

[2kwik4u]

I took it out yesterday. Three adults with a combined weight of 400 lbs. Gas tank was at 70%. Water was slightly choppy. It was very consistent wide wide open throttle to top out at 32 mph at 7,300 rpm. This is a 2021 SX190 with fresh oil change this season but did not change plugs. Any thoughts or ideas?

32mph at 7,300 rpm sounds a bit low, but pretty close. I usually cruise at ~30mph and ~7,000 rpm. My top speed is around 40-ish now with revs around 7,550. You're on the right rev/speed curve.......So, I don't think you have an issue with the pump or cavitation. You definitely need more revs though.

Here's a few things to check next.

With the engine off move the lever to full throttle forward. Open the engine hatch and see if you can physically move the throttle sensor (on side wall, I'll get pics of you need it) any further. Could be that you're lever is indicating full throttle, but you're sensor isn't adjust right.

Check the oil level when the boat is floating and level. Overfilled can cause excessive drag on the crank and pull your revs down a bit. You're only 2-300 revs away from full speed, so this is worth checking.

Check the air filter and make sure it's clear/fresh/clean. You can make a test run without it to see if that's the issue. Takes just a few minutes to remove and you won't hurt anything running without it for a short time.

Finally, throw some fresh 93 octane fuel in there. Your boat doesn't require it, but they often have detergents that can help clean the fuel system. It's a long shot, but a relatively inexpensive test.

 

[dvrice]

32mph at 7,300 rpm sounds a bit low, but pretty close. I usually cruise at ~30mph and ~7,000 rpm. My top speed is around 40-ish now with revs around 7,550. You're on the right rev/speed curve.......So, I don't think you have an issue with the pump or cavitation. You definitely need more revs though.

Here's a few things to check next.

With the engine off move the lever to full throttle forward. Open the engine hatch and see if you can physically move the throttle sensor (on side wall, I'll get pics of you need it) any further. Could be that you're lever is indicating full throttle, but you're sensor isn't adjust right.

Check the oil level when the boat is floating and level. Overfilled can cause excessive drag on the crank and pull your revs down a bit. You're only 2-300 revs away from full speed, so this is worth checking.

Check the air filter and make sure it's clear/fresh/clean. You can make a test run without it to see if that's the issue. Takes just a few minutes to remove and you won't hurt anything running without it for a short time.

Finally, throw some fresh 93 octane fuel in there. Your boat doesn't require it, but they often have detergents that can help clean the fuel system. It's a long shot, but a relatively inexpensive test.

Thanks! I’ll check all of these and report back.

 

[dvrice]

There is a pic of my throttle control at full throttle. This looks correct, right? Looks like the metal turn is touching the metal stop (as far as it can go)

 

[dvrice]

I also checked the oil (cold and on the trailer). It does look a little above the top hole so it looks a little over full. Should I draw it down and get it between the holes? Or wait and check it warm and on the water (level)?

 

[2kwik4u]

I also checked the oil (cold and on the trailer). It does look a little above the top hole so it looks a little over full. Should I draw it down and get it between the holes? Or wait and check it warm and on the water (level)?

Wait and check it warm on the water. Might consider drawing it down a little now, and taking whatever you draw out with you to add back. Easier to take a quart with you than to take a siphon with you.

Throttle looks OK. We're you able to rotate it any further by hand at full throttle? If you can still rotate it by hand, then adjust it a bit tighter and see if that helps.

Did the previous owner mess with the pump at all? I could also see a poorly tuned pump cone messing with revs by overloading the engine. Put the throttle full forward while on the trailer and take a picture looking forward from the nozzle into the cone. If there's an aftermarket pump cone that might cause it.

Check the exhaust outlet. If you have a restriction that could be hurting enough to drop revs. I can't imagine there is anything on there, but it's an easy check.

If that stuff doesn't help at all, might be time to get a YDS scan on the engine see if anything jumps out at you as wrong there.

I'm running out of ideas for what it could be to be honest. Would need to get my hands on it to troubleshoot any more. Where are you located?!? Maybe we can find a member nearby to get a second set of eyes on it.

 

[dvrice]

Here is the picture into my cone. I did suck some oil out and got it between the dots when warm and level. Still only getting 7,200-7,300 rpms

 

[2kwik4u]

Here is the picture into my cone. I did suck some oil out and got it between the dots when warm and level. Still only getting 7,200-7,300 rpms

That's the factory cone. Nothing awry there. Impeller looks pretty good from here, as well as clearances to the wear ring. Nice and clean with no corrosion or obvious damage.

Not sure why you aren't getting full revs at this point.

Did you try running without the air filter for a bit?

I did some testing this weekend with this thread in mind. WIth just the wife and I and a couple coolers aboard I was cruising in the 30mph range at ~6,750rpm. With the wife, 2 boys, dog, 3 cooler, and mother aboard yesterday I was cruising in the same 30mph range, but was up to almost 7,200rpm. Also had a noticeably longer time to plane with all the people aboard. Bow loading really kills speed, but I don't think that's your problem here. You're not getting full revs.

OOOOOO.......This just hit me.......The tach on mine isn't exactly accurate. That is to say the needle is a little bit below where the engine actually is. The needle might read 7,300rpm, but I'm getting 7,450-7,550 rpm. Also, the digital display on my gage is slightly different than the reported revs from my RideSteady unit. SO, there is a chance you're getting your full revs, but it's just not being reported correctly.......With that said I have no idea how to check other than hitting the rev limiter in the driveway and checking that against reported revs on the dash......which isn't the best idea. So, do that at your own risk.

 

[dvrice]

I appreciate all the input. I have not tried running without the air filter yet. I figured my air filter shouldn't be too bad on a 2021 with 80 hrs. Also, took a quick look and it looked like a little bit of a pain to remove. (a little more than just opening a housing and pulling it out)

I will say I had the boat fully loaded with 8 adults and three coolers yesterday and I was getting 29 mph at 7200rpm at WOT. I was pleased with that. Since I was only getting 32 mph with minimal loading I thought that was pretty good.

I also had no problem pulling one adult wakeboarder with 7 other adults on board. I did get bogged down and limited to about 23 mph at WOT when I had 5 adults on board and pulling a big tube/inflatable with 3 adults on it.

 

[2kwik4u]

I appreciate all the input. I have not tried running without the air filter yet. I figured my air filter shouldn't be too bad on a 2021 with 80 hrs. Also, took a quick look and it looked like a little bit of a pain to remove. (a little more than just opening a housing and pulling it out)

I will say I had the boat fully loaded with 8 adults and three coolers yesterday and I was getting 29 mph at 7200rpm at WOT. I was pleased with that. Since I was only getting 32 mph with minimal loading I thought that was pretty good.

I also had no problem pulling one adult wakeboarder with 7 other adults on board. I did get bogged down and limited to about 23 mph at WOT when I had 5 adults on board and pulling a big tube/inflatable with 3 adults on it.

29 with 8 people and 3 coolers doesn't sound terrible. Little slower than I would like, but certainly in the realm of acceptable. Definitely on plane and moving at least as fast as the pontoon boats

8 people and 3 coolers is DAMN crowded through for that boat. I'm impressed. I've had 6 teenagers and 2 adults on ours, and while we weren't attempting speed runs we were wakeboarding quite a bit and the little 190 did a fine job. It didn't jump out like a dedicated tow boat, but it didn't drown my beginners I was teaching either.

In terms of speed, next time out try something for me. Move the weight from the front to the back while watching speed, and not touching the throttle. We have a "no kids weekend" each year, and a few years ago I was the "shuttle boat" to the cove from the dock. One trip out I had my wife and I, and (2) other couples on board. One of the guys brought the largest effing Yeti cooler I've ever seen. It was so damn big that it just sat on the upper deck of the swim platform, we couldn't get it in the boat. On the way out, in the morning with all 6 people behind the windshield and stupid cooler on the back, we ran right at 42mph WOT from the dock to the cove. One the way back, aside from filtering some beers from the cooler through ourselves and into the lake, we had the same 6 people and the same stupid cooler. This time though it was late in the day and the "girls" sat in the bow. We only managed 37mph. 5mph drop just by moving 3 people into the bow. Same revs, roughly the same load (arguably a little lighter on fuel and beer), and same weather. That bow loading will absolutely KILL your speed. I've since re-arranged the storage on ours, and the only "heavy" stuff up front is the 22lb Navy Anchor I keep in the forward locker. Front port is blow up floaties and the umbrella, front starboard is kids toys. Coolers are under the port bench, tube and watersports crap is in the starboard rear seat. Mines lost a step or two in 7 seasons, and I top out at ~40mph with a light load now.

Only mods I have are a ribbon delete (removed spark arrestor), L13 Cone with 1 spacer removed (gold one), and a sealed intake tunnel. I've never had the impeller out of mine, and not done anything performance wise to the engine/exhaust. Now that I think about it, I'm still running on the 2017 air filter at ~240hrs. I should look into that.

 

[dvrice]

A little more info from today. I had 2 people (my wife and I), cooler and and other small stuff, and 46% fuel level. In fairly choppy water I was getting 29 mph at 6,750 rpm and 32 mph at 7,050 rpm. Those numbers seem pretty good. However, I just don’t get much after that and end up at 33 mph at 7,300 rpm at WOT.

 

[Carrie Fry]

Your RPM’s don‘t look too bad, you might be missing 150 rpms?

When I was doing my research on impellers for high altitude I looked at the dual impeller design… they are mainly for towing people, they have excellent bite in the water, but the sacrifice is in top speed.

How has it been over the last year?

Question for a rookie
We have a 2016 Glastron GTS207 Jet drive. Our boat was losing speed, went out one day and start of the trip would only go 30mph, on way back only 15mph. I reached out on this forum and was told to replace spark plugs. We did that and it made a world of difference at first. My husband got it up to 44mph and then it bogged down and after that couldnt get it over 33mph. It's running better but still not 100%. Suggestions please .

 

[FSH 210 Sport]

Four stroke or two stroke engine ?

 

[Carrie Fry]

Four stroke or two stroke engine ?

4 stroke