Need better holeshots fore Skiing

[Sako7STW]

We just spent the last 4 days out on our 2006 Utopia 205 (310hp). It did pretty good pulling the tubes and kneeboards. It dis OK pulling my skinny friends and kids out on the ski's and wake boards but me and my bro are bigger guys. Neither of us could get up on the ski's or wakebaords. the boat would cavitate or you couldnt get enough out of her without cavitateing to get us out of the water.

What do you suggest? Impellers, motor mods, sell this boat and get bigger one?

 

[seadoosnipe]

Impeller....?

We just spent the last 4 days out on our 2006 Utopia 205 (310hp). It did pretty good pulling the tubes and kneeboards. It dis OK pulling my skinny friends and kids out on the ski's and wake boards but me and my bro are bigger guys. Neither of us could get up on the ski's or wakebaords. the boat would cavitate or you couldnt get enough out of her without cavitateing to get us out of the water.

What do you suggest? Impellers, motor mods, sell this boat and get bigger one?

You can switch to a lower pitch impeller. That will probably help alot. I'd recommend you call a rep at Impros.com and see if they can recommend a something that will work.

I do know that when you do this, you will lose the top end speed. But, if the primary function of your boat is play, then it might be worth it.

There is one thing you bring up that is important to a jet pump type boat, weight.... If you are big enough, and create enough drag, you can keep the boat from moving by brute force. Now, if that boat had any forward momentum, you would not stop it.

The reason is a jet pumps theory of operation. Just like a jet aircraft, whose turbine works on "ram air"... a jet pumps performance is based on "ram water". What this means is, when you accelerate the throttle on these boats, nozzle pressure is buillt. But, it's not the maximum thrust. It can only achieve that thrust through forward momentum, as the water pressure is built in the suction cavity of the pump.

If you could jump start on a wake board or ski, verses sitting in the water, creating a huge amount of drag, I bet you 10 to 1, you could get up. Once the boat is moving forward, I doubt you could stop it.:cheers:

 

[Sako7STW]

Interesting, thank you for that input. Makes me wonder what to do for sure. I have another concern I have been wanting to look into and haven't yet and I guess now is a good time. I live at high elevation, 7000ft and will boating most of the time between 4500 and 8500ft. I bet 10 to 1 that this boat is set up for sea level. What changes should be made? I am betting maybe a different fuel mapping and a impeller change?

Any thoughts on that as well?

 

[moosehead]

I have similar high elevation locale as Sako, at 8,500' elevation.

Top end is also noticeably lower than at sea level in a 310hp Speedster 200, nearly 10 mph slower (similar ambient air temps). It would be interesting to hear member input for running in thin air, both holeshot and top end considerations. Thanks.

 

[C1800]

Thin air = smaller main jet in carb.

 

[Sako7STW]

Thin air = smaller main jet in carb.

Mine doesn't have a carb. I am not sure if the fuel injection is an open loop or closed loop system. Meaning, not sure if it has a O2 sensors or not and if so, what is its limitations on it's mapping for alt. adjustment. Then on top of that, a prop or impeller that is set up for sea level will not perform at my altitudes. my buddy just found that out with his Malibu. Set up for sea level, he changed the prop, and it's a totally different boat!

 

[C1800]

Fuel injection is fun, Do not have boat FI experience but my motorcycle (Yamaha R1) needed a few tweaks of the fuel map at certain throttle openings at corresponding RPMs. On the bike I have an after market "Power Commander" module that can be connected to a lap top and fuel maps loaded/modified. Wonder if they make something similar for the boats. Jetting/fuel mapping does need to be tweaked for thin air applications in most cases.

 

[Sako7STW]

I am going to call a few dealers today and see if they can "enlighten" me. I will post my findings.

 

[adermott]

DO a whip start

When we were younger we learned to ski slalom behind a 50 hp 15 foot outboard.

That would be fine for myself but a buddy of mine was 210lbs and it would drag him for miles. We finally figured out this whip start idea. leave about 10 feet of slack and have the boat go a little more parrallel to you to start instead of driectly away from you. You will pop out of the water in no time.

 

[parrothd]

Buy a Bigger ski....

 

[Squidoo]

Mine doesn't have a carb. I am not sure if the fuel injection is an open loop or closed loop system. Meaning, not sure if it has a O2 sensors or not and if so, what is its limitations on it's mapping for alt. adjustment...

My guess is that is that it is an open loop system using a mass air flow sensor as its primary tuning sensor. I doubt that it is closed loop, that is generally for emissions. Even it it had closed loop, it would go into open loop at full throttle anyway. If I'm right about the MAF, a MAF sensor should be fully capable of reducing the fueling to compensate for altitude, and you are experiencing the best that your engine(s?) can do at that altitude. And I think that I am right because it seems like you are saying that the boat runs fine, just with reduced power. If the fuel mapping were off, it would probably blubber and foul plugs.

If you never bring it down to earth, boosting your compression would be the first thing that I would do.

 

[Squidoo]

Fuel injection is fun, Do not have boat FI experience but my motorcycle (Yamaha R1) needed a few tweaks of the fuel map at certain throttle openings at corresponding RPMs. On the bike I have an after market "Power Commander" module that can be connected to a lap top and fuel maps loaded/modified. Wonder if they make something similar for the boats. Jetting/fuel mapping does need to be tweaked for thin air applications in most cases.

The problem with your tune was not that it was not correct for your altitude, but that the factory tuned it to reduce emissions. The Power Commander fixed these lean spots, and your bike should also be self-correcting for altitude. In other words, now that you have a power tune instead of an emissions tune, your bike should run fine at altitude, just with less power.

Nobody yet makes a piggyback, or any other type, of tuner for our boats as far as I know.

 

[Sako7STW]

I have been thinking along the lines of a turbo or a supercharger, any suggestions?

 

[moosehead]

Dunno about the SC Sako, but at 8,500' I'm only able to get about 6,100 max RPM's. Other's are having similar experiences up here. Boat runs fine otherwise, but like me, thin air definitely knocks her back a bit.

 

[rockytsi]

When we were younger we learned to ski slalom behind a 50 hp 15 foot outboard.

That would be fine for myself but a buddy of mine was 210lbs and it would drag him for miles. We finally figured out this whip start idea. leave about 10 feet of slack and have the boat go a little more parrallel to you to start instead of driectly away from you. You will pop out of the water in no time.

Please explain a further?

 

[revhardXP]

You should have no problem pulling skiers with that much HP – I remember pulling my dad (205lb) behind my old 89 SP with 580cc and that only has 56HP – the hole shot was no problem. If the boat is cavitating you'll need to check the jet pumps and wear rings. Without a good seal around the impellor, any jet boat will have trouble pulling a skier. Use a flashlight to check for grooves or pieces missing from the wear rings.

 

[kenny kustom]

I tried skiing behind my 2010 180 with 255hp. Couldnt do it. Too much cavitaion, and the jet spray was too much.

 

[JWLogsdon]

I have a 220hp challenger and am 6' 3" and weigh 270. My brother ways 300 and we both got up. we just make sure we only have 2 people in the boat.

we both know how to ski so that makes easier to get up also.

 

[iukaman]

OK, So I have figured out a trick to do this...

Teachign people to learn to wakeboard tend to want to ALWAYS pull the boat. They dont let the boat just bring them up...therefore creates alot of strain on it.

So, what I have done is this...

Have skiier in the water with taught rope
when ready angle boat 45 degrees or more (to the right lets say) and gun it, the boat will tend to circle the person slightly and then cut the wheel to the left (or opposite of angle before) and then you have a skiier up on plane.

By doing this, you are allowing the boat to get some forward momentum without having the drag of the skiier. If you can get that initial 2-3 second planeout or closer to it, you will have reduced alot of your drag from the boat itself.

This has worked with 4-5 people in the boat and I have the Speedster 200 with 310HP...just my 2cents - i knwo this is an old thread...but whatever

 

[parrothd]

You might want to have your pump/motor checked out, my challenger 1800(220 hp) can easily pull slalom skiers up, even with 5-6 people in the boat.. If you're teaching people how to wakeboard, you're going about it the wrong way. For wakeboarding you you slowly increase the throttle and slowly bring them up, maybe 20-30% power max. I have them crouch up in a ball, then idle, and slowly increase power, I tell them when they see the "wall of water" turn the board and stand up...Much easier....

 

[iukaman]

Yea i do that with a Malibu VLX - but the slow idle to increase teaches them how to control the board. The hard part is when they get the hang of getting up, they want to dig heals in. I start with my board completely underwater with about a 10 degree angle or so. Works just like an airplane...i pull out no problem behind the boat...it is just the newbies

Any good way to control sway from wakeboarding off a tower? Sense there is no transom in the water, I have found this to be a problem.....

all in all, i am glad to see other people using this boat for wakeboarding too!

 

[parrothd]

I just countersteer, it takes a lot of work to actually pull someone that's good.. Thank fully we're not...hehehe..

 

[Sako7STW]

Thanks for bringing this back to the top. It is still a problem since I have not been able to get the boat out yet this year. I am hoping funds are going to permit me getting my hands on a set of Skat-Trak Swirl impellers and new wear rings. Until then I am going to check my pumps and make sure they are sealed good. I had to take them off a few times last year. Once to fix a few little dings in the impeller thanks to rocks and a few times to clear ropes. Yes, we are newbies LOL. The boat would do 52 at first but once I put the system in it (a good 100+lbs) and the tower on it, I can only get it to do about 46. I have some special valve sealant that will work perfectly for sealing up the pumps. It is almost like a grease. Similar to o-ring sealant grease accept it is food safe and water safe.

What RPM's are you all running your motors up to? I have seen 7200 max and I have seen 8000 max on the Sea Doo site. Most I have seen mine hit was around 7700 when it was cavatating. The guy at Impros.com definitely said I need different impellers for my elevation. He said the Solas would do me well and I would lose less top end with it. The Swirl would turn it into a rocket of a holeshot but will lose more top end. BUT, he said I might not as well since the props will allow full RPM's and the extra RPM's might make enough difference to pretty well have the same top end. One thing that sucks though is having 2 motors so I have to buy 2 of everything but I wouldn't have it any other way!

Only time I have had my boat skid sideways was when my buddy was slalom skiing behind it and was way out to the side and just screaming. He isnt right in the head LOL. I just counter steered and was able to keep the boat pretty stable.