Who has experience with twin screw impellers?

[Dirtymunoz]

Just ordered a twin setup for my sx190 from impros and wanted to see if anyone had any experience running one of these? I primarily want to pull tubers and cruise with adults.

 

[King]

Watching, as I'm wondering about these also.

Would you be able to post a link to the one you picked up?

 

[jacoviii]

I would like to test this on my '22 255xd

 

[Wicked92]

I would like to test this on my '22 255xd

if they improve low speed hook up id def be interested, it might even help with surfing when we overload the boat with weight and give the speed control a fighting chance lol

 

[FSH 210 Sport]

Just ordered a twin setup for my sx190 from impros and wanted to see if anyone had any experience running one of these? I primarily want to pull tubers and cruise with adults.

When I was talking with Glen at Impros about high altitude impellers he mentioned these and they did look intriguing. However I still wanted some good top speed for long journeys. They are supposed to be excellent for hole shot and mid range cruising. Please let us know how they turn out for you! I’m always open to improving things.

 

[Dirtymunoz]

Well guys after a trip to the lake with the new dual impeller my experience with this boat is starting to fustrate me. At first take off I did manage to gain some speed with the new impeller off the hit. But im still only hitting 6500rpm and she takes about "no lie" 10 seconds or more to finally plane out. I'm thinking I have other issues. Max speed I was able to obtain with 7 people was about 12 mph rite at the boats weight capacity maybe 100lbs over. And 1 point I was able to touch 20 but after making a médium turn I dropped down almost instantly to about 10mph again. Right turns are just anchors for this boat, left handers were a lil better but still lost about 5mph. Kicked some people off the boat and tried about 600lbs of passengers and was able to plane around 7 seconds and achieved 30mph after about 1 1/2 minutes but same thing as soon as I turned instant anchor and dropped speed down to 15mph and that's not sharp turns either. Rpms would not for anything climb above 6500 rpms. When I did finally hit 30mph and tried to back off slightly off full throttle to cruise it would slow down to about 15 or less. It was a full throttle for everything day. I'm stumped and getting frustrated with this thing. Now to clarify the new twin pump did make it better than the original but at this point I'm not sure what the boats issue is. I'm watching videos online and people turn these things with no major loss of speed and plane out within 3-4 seconds. I checked for debris but found nothing. Also rpms from what I read should be 7500rpms. With my elevation at 4200ft I figure I mite loose some power but with the new impeller I'd figure I'd gain some back. I checked the spark plugs when I got home and they looked relatively new. Could still see the small v notch on the electrode from being newish. Checked the gap and found 2 of them around .038-.041 , manual if I read right calls for .032 . So I gapped all the plugs to match at .032 but maybe I'll just install new ones on the next outing. I really need some help on what else to check here. I've read about the intake tunnel sealant but from just looking I don't see much of it damaged or missing.

 

[FSH 210 Sport]

Sounds like you need to check other basics too.

too much oil in the engine
air filter clogged with oil
make sure the reverse bucket is open all the way at anything above TDE position

pretty simple to check the air cleaner problem, just remove it and make a few runs without it.

 

[Dirtymunoz]

I did check the oil aswell and it's right at the 2nd hole. Air filter was bone dry and clean. Maybe I'll take the filter out and remove the restrictor in the intake to see if it makes a difference. Also checked the reverse gate and it's completely out of the way in full forward throttle. When people say they seal there intake tunnel are they referring to just the silicone between the boat and jet pump housing assembly or is it something different? Any other things I should check or change?

 

[FSH 210 Sport]

I did check the oil aswell and it's right at the 2nd hole. Air filter was bone dry and clean. Maybe I'll take the filter out and remove the restrictor in the intake to see if it makes a difference. Also checked the reverse gate and it's completely out of the way in full forward throttle. When people say they seal there intake tunnel are they referring to just the silicone between the boat and jet pump housing assembly or is it something different? Any other things I should check or change?

Is your boats engine super charged? What octane fuel are you running ? How old is the gasoline in the tank and was it treated.

I read something in another thread about checking the clutch on the sc to make sure it is not slipping. Also in that same thread the boat was bought used and the guy was having some top speed issues although his boat is going much faster than yours is.

I take it you have checked to make sure you are getting full throw on your throttle in the engine bay? There is a test to check that the ETV electronic throttle valve is opening all the way too. The ETV is controlled by your cable actuated throttle.

 

[Dirtymunoz]

No it's the na 1.8 , as far as octane it was 87 octane. I did have 3/4 tank left over from the winter storage but I made sure to add the proper amount of fuel stabilizer for the months it didn't move. I did end up running it down to below 1/4 tank on this trip so next run I'll fill up with fresh 88 Oct atleast . Fuel is just sky rocketing and from what I've read it only requires 86 octane fuel.
Also yes I the reverse bucket being out of the way at full forward throttle.
Can you direct me to the link or info on checking the etv is functioning ?

 

[Dirtymunoz]

Also when I would just punch it full throttle from a slow drift she would climb to 6500 and not go any higher than that. I know elevation will factor some performance loss but im getting passed by fully loaded pontoon boats with 90hp motors. Wtf lol ?

 

[FSH 210 Sport]

No it's the na 1.8 , as far as octane it was 87 octane. I did have 3/4 tank left over from the winter storage but I made sure to add the proper amount of fuel stabilizer for the months it didn't move. I did end up running it down to below 1/4 tank on this trip so next run I'll fill up with fresh 88 Oct atleast . Fuel is just sky rocketing and from what I've read it only requires 86 octane fuel.
Also yes I the reverse bucket being out of the way at full forward throttle.
Can you direct me to the link or info on checking the etv is functioning ?

It’s in the service manual…. So there is no link.

Was it running better at the end of last season? If so what rpms was it then?

 

[lazergeek]

4200 Ft elevation you will defiantly need to repitch for that altitude. The 90 hp outboard you are comparing to is dialed in with a prop for that elevation. If you put a sea level prop that pontoon it wont go very fast either.

 

[FSH 210 Sport]

Also when I would just punch it full throttle from a slow drift she would climb to 6500 and not go any higher than that. I know elevation will factor some performance loss but im getting passed by fully loaded pontoon boats with 90hp motors. Wtf lol ?

I mix non ethanol 85 & 91 to get 86 octane.. truth be told I could probably just run straight 85 at my altitude of 5000’ but I occasionally go down to the 1200’ range.

Online mix calculator

Octane Mixture Calculator

 

[FSH 210 Sport]

4200 Ft elevation you will defiantly need to repitch for that altitude. The 90 hp outboard you are comparing to is dialed in with a prop for that elevation. If you put a sea level prop that pontoon it wont go very fast either.

Great point.

I have used this calculator for years now. It gives you an idea of just how much hp loss you will have. The rule of thumb is 3% hp loss per 1000’ of elevation gain, but that rule of thumb is assuming standard atmospheric conditions which rarely is the case. Temperature, barometric pressure, and dew point are major contribution factors in density altitude and the subsequent hp loss at altitude.

density altitude calculator

density altitude calculator for pilots

www.pilotfriend.com

For example, for me at 5000’ of elevation, rule of thumb is 15% hp loss. But on a summer day that hp loss is in the 30% range. It took me a while to get the pitch I wanted on my impellers but now I have a great compromise on pitch, rpm and altitude. I will be a bit under propped at the 1200’ range over at east river, but here at 5000’ so far I have been hitting 7900 rpm instead of 6900. A huge increase in performance.

 

[Dirtymunoz]

It’s in the service manual…. So there is no link.

Was it running better at the end of last season? If so what rpms was it then?

No last year is when I bought it used from Phoenix. Was only able to use it once last year due to work life but she ran horrible and couldn't even touch 20mph. The most was 18 going with the current. That's when I started to read on these forums for issues I could chase down. Glen at impros told me the dual impeller with altitude pitch for my area would help tremendously which it did in a way because atleast now I can hit 20 at times but it takes about 2 minutes or more to reach it and with just 3 people it will hit 30 but nothing more and even that takes a while to reach

 

[lazergeek]

Another way to look at it is our boats wont even plane until almost 5k RPMS so they are designed to run on the top half of the RPM Range. With altitude limiting your rpm's its hard to get any performance out of the boat.

 

[Dirtymunoz]

Ok so used that calculator you posted for altitude and it looks like currently the lake I go to with all the current weather inputs shows a altitude of almost 7600 ft elevation. Conditions are almost identical to what they were Saturday. So with that being said should I have Glen repitch it again for around 7500ft ?

 

[FSH 210 Sport]

No last year is when I bought it used from Phoenix. Was only able to use it once last year due to work life but she ran horrible and couldn't even touch 20mph. The most was 18 going with the current. That's when I started to read on these forums for issues I could chase down. Glen at impros told me the dual impeller with altitude pitch for my area would help tremendously which it did in a way because atleast now I can hit 20 at times but it takes about 2 minutes or more to reach it and with just 3 people it will hit 30 but nothing more and even that takes a while to reach

Okay how many hours on the engine? Have you run a compression test? Not trying to make you worry, just getting the necessaries out of the way.

There was another member here running up on the Utah mountains with a 195… he had to mess around with his impeller a bit to get the revs up. But he ran into cavitation issues on launching. Everything is a compromise.. if you run less pitch you can start to have cavitation issues when you punch it from a stand still, as that member did. He was so close that when it was hot it worked pretty well for getting him up on a single ski. But when it got cooler the pump would cavitate some due to the engine having more power.

If everything checks out okay, then you may have to send the impeller back to Impros and have more pitch taken out of it to maximize performance. The good news is that with the dual impeller set up the likelihood of cavitation goes way down.

Have heart and be patient. You will get this sorted out and will have a lot of fun once it is done. You could also have Impros pitch your oem impeller for high altitude first so that when you send the dual back you will have an impeller to use while Impros is doing their thing.

Trust me when I tell you that getting the impeller sorted is well worth while. My oem impellers were only getting me roughly 29-31mph top speed up here, and after I got the impeller sorted I’m now going between 39-41 mph… that’s a 30% increase in top speed. Like your experience my boat would slow dramatically when making turns. Now there is a lot more reserve power if you will so when making turns it does not slow down nearly as much. I’m looking forward to pulling some tubers this summer and not have my boat struggle so much to stay on plane with people on board, but to have that extra power to be able to get the tubes out of my wake. One time last summer I had 6 people on the boat and was pulling two people on Big Mable, the only way to get on plane was to go down wind-no kidding- and if I turned it would come off plane. Pretty disappointing. I’m sure that this summer I will be able to have that same load of people and possibly more and be able to tow BM just fine. I did lose a little fuel mileage, about .3 mpg, with the high altitude impellers, but the trade off in performance was well worth it.

 

[Dirtymunoz]

Okay how many hours on the engine? Have you run a compression test? Not trying to make you worry, just getting the necessaries out of the way.

There was another member here running up on the Utah mountains with a 195… he had to mess around with his impeller a bit to get the revs up. But he ran into cavitation issues on launching. Everything is a compromise.. if you run less pitch you can start to have cavitation issues when you punch it from a stand still, as that member did. He was so close that when it was hot it worked pretty well for getting him up on a single ski. But when it got cooler the pump would cavitate some due to the engine having more power.

If everything checks out okay, then you may have to send the impeller back to Impros and have more pitch taken out of it to maximize performance. The good news is that with the dual impeller set up the likelihood of cavitation goes way down.

Have heart and be patient. You will get this sorted out and will have a lot of fun once it is done. You could also have Impros pitch your oem impeller for high altitude first so that when you send the dual back you will have an impeller to use while Impros is doing their thing.

Trust me when I tell you that getting the impeller sorted is well worth while. My oem impellers were only getting me roughly 29-31mph top speed up here, and after I got the impeller sorted I’m now going between 39-41 mph… that’s a 30% increase in top speed. Like your experience my boat would slow dramatically when making turns. Now there is a lot more reserve power if you will so when making turns it does not slow down nearly as much. I’m looking forward to pulling some tubers this summer and not have my boat struggle so much to stay on plane with people on board, but to have that extra power to be able to get the tubes out of my wake. One time last summer I had 6 people on the boat and was pulling two people on Big Mable, the only way to get on plane was to go down wind-no kidding- and if I turned it would come off plane. Pretty disappointing. I’m sure that this summer I will be able to have that same load of people and possibly more and be able to tow BM just fine. I did lose a little fuel mileage, about .3 mpg, with the high altitude impellers, but the trade off in performance was well worth it.

Thank you , That right there gives me hope honestly. Exact same scenarios for me and this boat and if you were able to get them resolved than it gives me hope that it is just the repitch that is needed. I was hoping the 4500 pitch on the new dual would be enough but never thought about actual altitude with the other factors in play. Let me know how your boat does with big Mable. I've been wanting to get a 3 seat tube but with just this 2 seater and boat issues I didn't wana spend money anymore lol