SeaDoo Gas Milage & Maintenance

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hibbert6

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Thanks so much for answering my questions on backing up a jet boat. Now I need to know

1. If there are any maintenance differences between a SeeDoo (Rotax?) and a typical v6 i/o.

2. How are the SeaDoos on gas usage? (For general water ski & tubing use) again, compared to, say, a v6 i/o?

Thanks!

Dave
 

Joshua Nichols

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Re: SeaDoo Gas Milage & Maintenance

I have a friend on here that had one... I will forward your post to him
 

smclear

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626
Re: SeaDoo Gas Milage & Maintenance

Thanks so much for answering my questions on backing up a jet boat. Now I need to know

1. If there are any maintenance differences between a SeeDoo (Rotax?) and a typical v6 i/o.
2. How are the SeaDoos on gas usage? (For general water ski & tubing use) again, compared to, say, a v6 i/o?

Thanks!

Dave

I have the Sea-Doo Speedster SCIC. Maintenance on the engine is similar to a V6. If you get the supercharged version it will require additional service when winterizing. Not a big difference really. The outdrive on an I/O does require maintenance that would not be required on the pump of a jet.

I can not speak to the fuel efficiency of the normally aspirated (non supercharged) engine. The supercharged versions fuel efficiency sucks compared to my old V8 I/O. And it requires premium fuel to add further pain. But it's a little rocket and a blast to drive/ride in. If it were my only boat, I'd probably trade it in just based on fuel consumption. I keep it because I have another boat for skiing and tubing and it's so much fun.

The Yamaha's supercharged 1800 CC engine does not require premium fuel and is very equal in performance. Don't rule them out.
 

Bondo

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71,088
Re: SeaDoo Gas Milage & Maintenance

Thanks so much for answering my questions on backing up a jet boat. Now I need to know

1. If there are any maintenance differences between a SeeDoo (Rotax?) and a typical v6 i/o.

2. How are the SeaDoos on gas usage? (For general water ski & tubing use) again, compared to, say, a v6 i/o?

Thanks!

Dave

Ayuh,... #1,.. They have Nothing in common...

#2,.. Jetskis are notoriously Ineffecient...
 

Joshua Nichols

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Re: SeaDoo Gas Milage & Maintenance

I think he may be asking about those little Seadoo jetboats... Shoot they have those that are 20ft and greater...
 

Bondo

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Re: SeaDoo Gas Milage & Maintenance

I think he may be asking about those little Seadoo jetboats... Shoot they have those that are 20ft and greater...

Ayuh,... They're still nothing but a Glorified Jetski...
 

H20Rat

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Re: SeaDoo Gas Milage & Maintenance

I think he may be asking about those little Seadoo jetboats... Shoot they have those that are 20ft and greater...

24 footer, with comparible space to a 26 ft i/o... Thats one big jet ski! Not sure why people think they are glorified jet skis, especially when they have no personal experience driving or riding in a big modern jet boat.
 

scooper77515

Senior Chief Petty Officer
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Re: SeaDoo Gas Milage & Maintenance

The older and smaller seadoo jetboats are nothing but a Glorified Jetski... really.

I don't have experience with the 4 stroke seadoos, but the 2-strokes are WAY more maintenance than an I/O. The gas mileage is pretty good though. Especially when you consider that you are riding around at 6000-7200 rpms most of the time.

I found that there was MORE maintenance on a jet pump than there is on an I/O. If you use it roughly. Sandy water, or the occasional rock, ski rope, stick, etc will get into the pump and tear holes into the wear ring, which will SIGNIFICANTLY reduce your propulsion and increase cavitation. Even one small rock can make a mess out of the wear ring, and most likely the impeller. It is mostly plastic and much easier to take out than the entire outdrive on a I/O, but the parts are expensive, and unless you live near a good seadoo shop, you are looking at 2 weeks turn around for any repairs you do yourself. Sunday afternoon tear down, order parts on Monday. Wait til the following monday or tuesday to get the parts, and maybe, if you have time, put it together during the week and back on the water the following weekend, but most of us work all day and need to use the weekend to get it back together, so there is a SECOND weekend out of the water. Because of a rock or ski rope.

My other complaint with the 2-strokes is that they are hypertuned...running at full capacity right on the verge of self-destructing. So any small adjustment out can destroy the engine. Broken or leaking 99 cent oil line? Blow the engine. Running a little lean on one carb? Blow the engine. Accidentally put the wrong oil in mixing two brands? Blow the engine.

I sold my 97 Challenger, and gave away my 96 XP. There was a reason I did that and went with an I/O. I spent too many weekends fixing stuff and not on the water riding.

Keep in mind this is all in relation to a 2-stroke, so if you have a 4-stroke, I have no idea how much of this is still true (the jet pumps are still similar).

The superchargers are notorious for failing at around 100 hours, and when they do, they usually take the engine with it. They used to use (maybe still do?) ceramic washers in them, and when they failed, they shattered and little chunks of ceramic go through the intake making a mess.

But overall, if you don't mind paying for maintenance, or can do it yourself, and the jetboats are running fine, they are a blast to ride around on. Mine was single engine 110 hp 787 model, and it pulled me up on wakeboard (after i put in a lower pitch Swirl impeller and new wear ring). But we ran out of room after 3 people, and it wouldn't plane with 4 without a 1/2 mile long runway!
 

H20Rat

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Re: SeaDoo Gas Milage & Maintenance

Ayuh,... #1,.. They have Nothing in common...

#2,.. Jetskis are notoriously Ineffecient...

??? are we talking the same thing here? I know you are one of the old dogs here, but seriously, you have no idea what you are talking about...

So here are the facts. Fuel consumption. I picked two random comparible boats, Yamaha sx210 21 footer, dual engine and a Four Winns H210. Very similar boats, although the yamaha has far more room inside. (i've personally ridden in both of those) Anyway, fuel economy. Here is the best cruising speed, yamaha first.

RPM MPH MPG
6000 31.1 3.98

And the four winns
RPM MPH MPG
2500 21.3 3.59
3000 30.3 3.41

So best cruise, at nearly the same speed, the I/O gets worse economy. A quick glance over the chart shows that is true for the entire range!! (Go look it up on boattest yourself if you need verification.) The boats have similar power, but the four winns is 700 pounds heavier or so, mostly because of drivetrain. Obviously, I'm sure you could find jet boats that are worse, and I/O's that are better. I picked 2 at random, but the point is there is very little, if any, difference.


And second, how do they not have anything in common? They are both 4 stroke engines. As far as engine maintenance goes, it is very, very similar.


And LASTLY, i promise! Jetskis are one of the most efficient planing crafts out, period. Find a boat that can do 10.21 mpg at 31 mph. I bet you can't... I picked a random pwc (Yamaha VX Cruiser) from boattest and that is the mpg's at best cruise. Even wide open throttle at 54 mph gets you 7.25 mpg. There is NO boat that will do that. PWC's got that reputation because people tended to ride them hard, not because of inefficient designs. If you drive a boat like a PWC is often driven, you will get worse mileage. I looked up on the stats on my old ('97) 2 stroke seadoo. Even at WOT, it still gets 5.45 MPG at 54 mph. Find a 2 stroke boat/engine combo from that time period that gets that mileage... The only thing that I can think of that might be comparible are those go-fast long nose 2 seater's. (hydrostreams and their relatives) Not sure if there are any in production yet though...
 

1979checkmate

Petty Officer 1st Class
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Messages
261
Re: SeaDoo Gas Milage & Maintenance

take a look at that again and make sure you didnt have a typo.. 3.98 mpg for yamaha, 8.9 mpg for four winns??? Unless that is supposed to be Gallons Per Hour, in which case, yes your data shows better fuel consumption with the jet. This is not meant to be rude or anything, i would just like some clarification, why do some people like the jets so much. I agree they are kinda cool looking, and great for running shallow and throwing a rooster tail, but for me thats where the good things end. I mean a jet pump is the least efficient at moving a boat through water compared to the other major propulsions, a prop will always be more efficient. any 2 boats with the same HP one i/o and one jet, the i/o will run faster.

EDIT: you changed the mpg-lol i was confused for a second at the logic.
 

H20Rat

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Re: SeaDoo Gas Milage & Maintenance

take a look at that again and make sure you didnt have a typo.. 3.98 mpg for yamaha, 8.9 mpg for four winns???
EDIT: you changed the mpg-lol i was confused for a second at the logic.

I mean a jet pump is the least efficient at moving a boat through water compared to the other major propulsions, a prop will always be more efficient. any 2 boats with the same HP one i/o and one jet, the i/o will run faster.

Yep, typo... I copied boattest's chart and deleted the extra columns... 8.9 was one column too early, its gallons per hour.

Yep, jet pumps are less efficient, but they are also substantially lighter. So it isn't always true that given the same HP, the IO will be faster (or obviously more efficient overall). It depends on how the hull carries the weight also, as well as propping on the I/O. I suspect if the four winns in my example above was 700 pounds lighter, it would have had the mpg advantage as well.
 

smclear

Chief Petty Officer
Joined
Jul 14, 2008
Messages
626
Re: SeaDoo Gas Milage & Maintenance

The older and smaller seadoo jetboats are nothing but a Glorified Jetski... really.

I don't have experience with the 4 stroke seadoos, but the 2-strokes are WAY more maintenance than an I/O. The gas mileage is pretty good though. Especially when you consider that you are riding around at 6000-7200 rpms most of the time.

I found that there was MORE maintenance on a jet pump than there is on an I/O. If you use it roughly. Sandy water, or the occasional rock, ski rope, stick, etc will get into the pump and tear holes into the wear ring, which will SIGNIFICANTLY reduce your propulsion and increase cavitation. Even one small rock can make a mess out of the wear ring, and most likely the impeller. It is mostly plastic and much easier to take out than the entire outdrive on a I/O, but the parts are expensive, and unless you live near a good seadoo shop, you are looking at 2 weeks turn around for any repairs you do yourself. Sunday afternoon tear down, order parts on Monday. Wait til the following monday or tuesday to get the parts, and maybe, if you have time, put it together during the week and back on the water the following weekend, but most of us work all day and need to use the weekend to get it back together, so there is a SECOND weekend out of the water. Because of a rock or ski rope.

My other complaint with the 2-strokes is that they are hypertuned...running at full capacity right on the verge of self-destructing. So any small adjustment out can destroy the engine. Broken or leaking 99 cent oil line? Blow the engine. Running a little lean on one carb? Blow the engine. Accidentally put the wrong oil in mixing two brands? Blow the engine.

I sold my 97 Challenger, and gave away my 96 XP. There was a reason I did that and went with an I/O. I spent too many weekends fixing stuff and not on the water riding.

Keep in mind this is all in relation to a 2-stroke, so if you have a 4-stroke, I have no idea how much of this is still true (the jet pumps are still similar).

The superchargers are notorious for failing at around 100 hours, and when they do, they usually take the engine with it. They used to use (maybe still do?) ceramic washers in them, and when they failed, they shattered and little chunks of ceramic go through the intake making a mess.

But overall, if you don't mind paying for maintenance, or can do it yourself, and the jetboats are running fine, they are a blast to ride around on. Mine was single engine 110 hp 787 model, and it pulled me up on wakeboard (after i put in a lower pitch Swirl impeller and new wear ring). But we ran out of room after 3 people, and it wouldn't plane with 4 without a 1/2 mile long runway!

It is very true that the older two strokes are considerably more maintenance. I had a 97 Yamaha jet ski that was HIGHLY modified and required rebuilding twice a year. But it was wicked fast. At fifty, I found myself not wanting to hassle with it any more. Hence the jet boat. The more modern four strokes are just like any other four stroke engine.

I am going on my fourth season with it and have yet to have any issue with the pump. I have heard of others who have. I guess it depends on the condition of the waterways you cruise. Still, if you are even slightly mechanically inclined, changing the wear ring is not too difficult. Not the easiest thing to do, but still not that bad. I have helped change one on a jet ski or two.

The ceramic clutch washers are known to shatter and if it happens, could easily fry the engine. They are very easy to replace with the right tools. Takes about an hour. Less if you know what you're doing (read experience). Beginning in 2008 (may be 2009) they are no longer using the ceramic washer. Yamaha uses a different supercharger style and doesn't have those issues.
 

1979checkmate

Petty Officer 1st Class
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Jan 15, 2011
Messages
261
Re: SeaDoo Gas Milage & Maintenance

Thanks, ill admit the jet boats look pretty sexy. I think i'll stick to my outboard and get lightweight and a prop :). although a 30 year old Mercury Tower isnt exactly efficient :facepalm: . To each his own smokingcrater :cool:
 

Bondo

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Messages
71,088
Re: SeaDoo Gas Milage & Maintenance

24 footer, with comparible space to a 26 ft i/o... Thats one big jet ski! Not sure why people think they are glorified jet skis, especially when they have no personal experience driving or riding in a big modern jet boat.

Ayuh,... I ain't gonna argue 'bout it,...
But,...
A boat built with a Jetski motor, 'n pump, or 2, or 3....
Is Still a Glorified Jetski,...

Plain, 'n simple...
 

Hogger

Petty Officer 1st Class
Joined
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Messages
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Re: SeaDoo Gas Milage & Maintenance

Gas milage sucks, but... It's just a glorified jetski. Lol.
Jet boat
 

scooper77515

Senior Chief Petty Officer
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Sep 3, 2010
Messages
753
Re: SeaDoo Gas Milage & Maintenance

WOW! I am glad I clearly stated that my opinions are based on the 2-stroke models, otherwise I would have been blasted as bad as everyone else!!! :D

I don't have experience with the 4-strokes, and will not make any comments on them, other than the couple of issues I have heard about REPEATEDLY on another Seadoo-related forum I frequent.

I agree...the pwcs are WICKED fast. I was cruising my newly rebuilt 96 XP at just shy of 60 mph. That is 110 hp on a 400 lb craft, with another 200 lbs of tub-o-lard riding it. It could get really hairy really fast!!! And it got to that top speed in about 2 or 3 seconds. No wasting time there! And it would jump the hell out of waves. I used it primarily to "surf" in the waves off the Texas coast. Did some wakeboarding and tow-surfing behind it too. But primarily getting 8-10' airs off 4-6' waves. Maybe more at times.

The boat was fun, as well. And it was pretty fast, about 44mph with me in it alone (even after the new impeller which took off a mph or two). But both required LOTS of maintenance. It was all easily accomplished in the driveway or garage. Well, not "easily"...it is difficult working in those enclosed spaces, and upside down, often.
 
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