951 DI clarification needed

[68ragtop]

Hi Guys, I am aware that the 951 DI engines are bad news in general, & from what I found on this forum it sounds like they have an expected life of 200 hours on the high side. Is this because of fuel related issues from the fuel pump, injectors, or other things that make them run lean & melt down, or is there also an internal engine component to this limited life conundrum?

When they need a rebuild, is it primarily the top end that fails prematurely, or do these engines have crank isssues, etc as well. In otherwords, if an engine doesn't scatter its top end into the rest of the engine, does the rest of it hold up well? What else usually needs updating or replacing as these age?


Are there worse years than others? If I pick one of these up as another project ski, will it require specific sea-doo tools that I might not already have?

Thanks for the schooling, 68RT

 

[SabrToothSqrl]

Let me start by saying the 951 is not a bad engine, nor is direct injection.

the 951 gets a bad reputation, because, yes, it runs about 200 hours between rebuilds. This is a money saving practice, and business practice known as http://en.wikipedia.org/wiki/Planned_obsolescence. If the engine was designed/built to with a 300 or 400 hour life, it would surely cost more.

200 hours is 20 hours of riding for 10 years. 10 years is what SEA-DOO was aiming for when it made these skis... 15 years ago! The fact that many of them still run, to this day is actually quite amazing.

When your engine of 200 hours does go. Rebuild the WHOLE thing. Replacing a top end may buy you a season, maybe two, but you are running an 11-15 year old crank, bearings, seals, and more. Do you really want to do all this all over again next year and miss 1/2 the season? Finally, 130HP from 951cc is damn near amazing. These engines are more like a race car engine than a 4 banger honda. They are run hard, hot, and fast, then they sit for 9 months, only to do it all again. They never get an easy ride. Then they sit for months, and months.


As for the DI: SEA-DOO was under pressure to improve the emissions from these engines. DI is a great way to do that, improve starting, and fuel efficiency. However since they only had it for a few years, there are some bugs that creep in. Under powered rectifier, impossible to reproduce fuel pumps. These don't make them bad, they are just more complex than carbs. They are also now 10-15 years old... how old was your last car when you sold it? 15 years? Did it run? I bet it had a much easier life than these engines.

The 99-02 was the best 951 engine

97.5 - white 951 - run from this engine. run far away
98 - grey 951 - muffler is exposed and not inside rubber/foam 'cover'
99 added dual coil ignition + different magneto cup
2000 added different air scoop flaps
2001 added an improved exhaust manifold using a rubber gasket (vs paper).
and some year added the rubber 'recovery envelope'... I forget which year, but I always run them.

But hey; what do I know what 951s?

 

[Dr Honda]

Ummmmmm......


Yep... what he said. :thumbsup:

 

[SabrToothSqrl]

Also, if you aren't regularly rebuilding these, find a reputable shop that will rebuild it and give you a 1-2 year warranty.

The cost difference isn't much, and it's done right, with a warranty.

 

[Spimothy Leary]

ya, pretty much...

the DI's scare me, not the engine itself, which I don't think is more or less prone than any other 951 to failure, but all the gizmo's and doo dads that keep it running, with that said, i'd rather part one out than fix it, assuming its in non running condition and needs a rebuild. which is a shame to some degree, since when running, they are excellent ski's. If its running, but poorly, its probably worth fixing, but you might run into a steep learning curve if you've never messed with a DI.

the only thing that this helps, is since the secondary market now has a lot of DI part outs on it, its helping keep the prices reasonable for parts. duly noted I said reasonable.. not low...

 

[Coastiejoe]

Nice post SabrToothSqrl...

Good information..

 

[68ragtop]

Not trying to repair a failed ski I own. Well, not just yet..... What got me into seadoo's isn't actually the desire to ride them. I work in electronics in my career, & am a hobbyist car builder. I have a passion for rebuilding anything engine powered. Snowmobiles, motorcycles, & more recently PWC's Been doing that since I was 16 nearly, 30 years ago.

so that being said, I would probably never buy a running ski. I bought five of them so far & not one of them ran when I brought them home. It's my passion & mental therapy. I recently located a 2000 RX that has lost the top end, & seeing I have not dealt with one yet, I thought I would see what I can learn about them here first before I dive in.

I just didn't want to buy it & learn after tearing it down that all the 951 skis need new or updated fuel injectors, or the cranks chronically fail. Or worse to me, maybe it requires a specific dealer only diagnostic tools to test specific parts that I can't do in my shop. (just an example, not saying any of this in the case)
All the usually wear and tear related items on the 580-787 carbed engines I am very comfortable with.

 

[lamajama]

As for the DI: SEA-DOO was under pressure to improve the emissions from these engines. DI is a great way to do that, improve starting, and fuel efficiency. However since they only had it for a few years, there are some bugs that creep in. Under powered rectifier, impossible to reproduce fuel pumps. These don't make them bad, they are just more complex than carbs. They are also now 10-15 years old... how old was your last car when you sold it? 15 years? Did it run? I bet it had a much easier life than these engines.

The 99-02 was the best 951 engine

97.5 - white 951 - run from this engine. run far away
98 - grey 951 - muffler is exposed and not inside rubber/foam 'cover'
99 added dual coil ignition + different magneto cup
2000 added different air scoop flaps
2001 added an improved exhaust manifold using a rubber gasket (vs paper).
and some year added the rubber 'recovery envelope'... I forget which year, but I always run them.

But hey; what do I know what 951s?

hey Sabr, when you say "impossible to reproduce fuel pumps" - what is your opinion on the HFP-RTN
non-OEM fuel pump that was discussed in this thread:

http://www.seadooforum.com/showthread.php?46680-DI-Seadoo-Fuel-Pump

In this thread, one member had issues with this non-OEM part and I have not read of any negative issues with
any other of those in the Forum that have used this pump. Could be one bad experience in terms of quality control
bit I am interested in your thoughts on that possible alternative to the $1000 OEM pump....

 

[SabrToothSqrl]

I've seen some on eBay with lifetime warranties, however I have no first hand experience with them. Sorry.

 

[BMANN06]

Nice post sabr, (btw sorry if I negged you, I hit the thumb icon to give you props and its now red ... no idea )

Not hijacking but my question kinda sorta fits this thread ... does anybody know the difference between rotax di and rotax sdi?

I'm in the process of rebuilding my sdi 1000 from my sled (which is extremely similar to the 951). just curious, i know that sdi is "semi direct injection"

 

[SabrToothSqrl]

I never worked on the sleds. I would like to put there 160 HP 2 stroke in a ski though.

 

[BMANN06]

I never worked on the sleds. I would like to put there 160 HP 2 stroke in a ski though.

That would def. be cool, I think they may be pushing more than a 160 though, you never know with rotax motors though, they aren't the easiest motors to stick to a dyno. Just like the 951 though your basically doing a full rebuild at 200hrs, my motor is running fine but i'm doing a complete overhaul I'm at 120hrs. Getting stuck on the trails in the middle of nowhere with a blown motor is about as much fun as being stuck out in the middle of a large lake with a blown motor.

 

[SabrToothSqrl]

At least on the trail you don't have to swim for it.

 

[68ragtop]

I never worked on the sleds. I would like to put there 160 HP 2 stroke in a ski though.

I think that's part of my fascination with the skis. By comparison, the skis are pretty simple. no suspension, no clutching, brakes, etc.
Many of the sleds are going 4-stroke turbo's & building upwards of 200HP crazy mid range & top end speed. I still love the 2-strokes though, just seems like the correct power plant for the sport. I have been an arctic cat guy forever on the sleds, however I recently picked up an Ski-Doo MXZ 800ho for the wife. While I haven't found the ski-doo's do be as quite as quick as the cats, I am impressed with the fit & finish of the doo's Very well engineered & easy to work on.

 

[68ragtop]

At least on the trail you don't have to swim for it.

I had catastrophic engine failure on a sled, in the upper michigan two seasons ago. The guys I was with went back to our hotel to get the trailer. I had to wait in the woods as night feel for about 2 hours. That was creepy. so quiet all I could hear was my ears ringing.

 

[SabrToothSqrl]

I think that's part of my fascination with the skis. By comparison, the skis are pretty simple. no suspension, no clutching, brakes, etc.
Many of the sleds are going 4-stroke turbo's & building upwards of 200HP crazy mid range & top end speed. I still love the 2-strokes though, just seems like the correct power plant for the sport. I have been an arctic cat guy forever on the sleds, however I recently picked up an Ski-Doo MXZ 800ho for the wife. While I haven't found the ski-doo's do be as quite as quick as the cats, I am impressed with the fit & finish of the doo's Very well engineered & easy to work on.

Actually, Sea-Doo does have models with suspensions

 

[can128]

I have a 2000 GTX DI with 249 hours. I believe I require a new rectifier... Can anyone lead me to a part number? Ive been looking on www.regulatorrectifier.com but can't seem to find exactly what I need.

Any help would be greatly appreciated.

 

[Spimothy Leary]

according to google/amazon...
http://www.amazon.com/Rectifier-Voltage-Regulator-278001554-2000-2003/dp/B006PJH86O

caution, i put less time into the google search than it took to read your question so....

278001554

 

[can128]

according to google/amazon...
http://www.amazon.com/Rectifier-Voltage-Regulator-278001554-2000-2003/dp/B006PJH86O

caution, i put less time into the google search than it took to read your question so....

278001554

Fair enough. I belong to several different forums (cars, watercrafts, snowmobiles, etc...), and I should have known a question like that was going to lead to someone responding with advice to search more...

Nonetheless, thanks for the response.

 

[lamajama]

I've just ordered one of these as I've heard great things about them...

http://www.osdparts.com/index.php?main_page=product_free_shipping_info&cPath=6&products_id=8

 

[SabrToothSqrl]

I was also going to suggest the heavy duty one

 

[can128]

I've just ordered one of these as I've heard great things about them...

http://www.osdparts.com/index.php?main_page=product_free_shipping_info&cPath=6&products_id=8

I was also going to suggest the heavy duty one

Thanks guys... What do you think of this one? It's a little less expensive too...

I'm not even sure the rectifier needs replacing on my machine but after 239 hours, I'm pretty sure the original rectifier is still in there... Is it a good idea to change it even though it may not need replacing??

http://www.regulatorrectifier.com/c...ifier?osCsid=bbab0c6a2ed5038a2ad8f9ad94ae6d92

 

[lamajama]

Interesting unit. I know I've read that the 4 stroke unit works very well (which is what I linked to) because of the heavy duty
nature of it vs the 2002 OEM unit. Your link appears to have the "higher output" @ 40 amps but I think we need someone more qualified
to answer what this means vs the 4 stroke unit I linked to....

Of course I just ordered a $124 one vs this $89 one (which hopefully is a "drop in" unit as well).

I look forward to hearing the expert's opinion on this cheaper unit.

As far as changing it, I understand it's a matter of time, and with your hours it's probably sooner rather than later. The reason
I ordered mine is that I want it on hand for when one of mine goes. I just replaced one with an OEM (last year prior to
seeing these options) and as I say want a cheaper unit waiting. If I were you I'd use the current one until it dies and have a new
one ready but that's just my thoughts.

 

[can128]

Experts: feel free to chime in... Let us know what you think of the 40 amp $89 rectifier, because that is definitely the one I am leaning toward.

 

[can128]

I just purchased this one... http://www.regulatorrectifier.com/ca...d8f9ad94ae6d92

Should receive it within 6-10 days. I'll let you guys know if my machine blows up.

Also.. should I replace my rectifier before it actually goes out? I'm a believer in 'if it aint broke, don't fix it' but I'm not sure if that applies here...

Let me know what you guys think.