Reliability of 3D Di

[ProbeGT]

Hi guys

I currently have a Sea-Rayder F16 boat that I'm trying to sell to buy a 3D Di with the 951 engine.

I know bombardier products have very different reliability from one product to another.

Are those skis reliable? I'm a good home mechanic and I can to about everything (except rebuilding the engine) What are common problems and the cause of them?

Basically i want to go for the 951 because i heard it's more reliable, better on fuel and more powerful than the 780ish ? I know they are no longer produced, and I know what it is to have a discontinued product (sportjet 120 in my boat) and that scares me a little for part availability.

In other words, is it a very very funny money pit, or it's a good machine capable of handling a good beating?

 

[magical]

i bought a broke 3ddi as it wasnt looked after by previous owner (ran it with no oil in ) but i found a good seadoo mechanic who is rebuilding it for me i asked loads of questions as i heard they had loads of problems to and he told me they are good engines if looked after rite but with it being a high power two stroke after giving it a little beating slow down to let things cool down and breath and give it a beating again but also to make sure its fogged after every use my mate has the xpdi 2003 he had it from new and he has had no work done to engine and it still runs great

 

[ProbeGT]

Why does it need to be fogged after each use?

with what do you fog it?

 

[magical]

i was told from the mechanic im useing and by my mate who has always fogged after each use hence he hasnt had any problems that its best to keep it lubed inside as it disperses any water that might be lying inside engine even condensation which can lead to little rust spots so for the sake of 5 mins of time and a £3 tin of fogging spray its worth it rather than letting rust set in as then its just a ticking time bomb

 

[seadoosnipe]

DI...

DI, or direct orbital injection is not the most reliable in a Rotax motor. The best fuel injection system by Rotax is the RFI, which is acronym for Rotax Fuel Injected.

The DI is a high pressure, 2 part injection system. It uses a secondary component in the fuel rail to deliver fuel to the engine, an air compressor.

To overcome the compression stroke, the fuel rail injector first opens and drops a pre-determined amount of fuel into the injector, then the compressor applies pressure and when commanded by the MPEM, opens and injects a burst of fuel, which is atomized by that air. This also adds to combustion so the restriction of intake air (or manifold pressure) is different on this model, than others.

This motor is one of the hardest to troubleshoot and maintain. BRP repair shops love them because it's like a guarantee to them having money coming in for a good paycheck. Personally, I do not like this type injection system. It's too complicated. The RFI system is a low pressure injection system that operates solely on the fuel pump. It injects to the low pressure side of the intake. I have seen very few issues with this type system. It's the most reliable of the two.

FOGGING? .... this can be done or not, depending on your geographical location and the amount you ride. Fogging is done to apply a barrier coat on all your internal components (bearings) to keep the humidity or any moisture from building and forming rust. Which, if not run, will pit your roller balls of the bearings and eventually lead to bearing failure.

If your a weekend rider, then fogging isn't really necessary. If you live in a humid environment, like Scotland or Oregon/Washington, ...and are not going to ride for several weeks to a month, then I'd either fog, store inside, or have some type of heat source to keep the humidity levels down. You can determine how bad you build humidity by exposing your motor after being shut up for a couple days. If you have water droplets forming all over the tuned pipe, that same moisture is finding its way into your motor.

If it's not raining, your best to leave your engine compartment cracked open to the outside, to vent moisture. The amount of humidity can also be controlled through making sure all your bilge water is removed. In winter, I use a shop vac to do this.:cheers:

 

[ProbeGT]

Thanx for all this info seadoosnipe

I'm a week-end rider and does not live in a very humid country.

As far as reliability, except the complex injection system, is it an engine prone to blow up? Or wear quite quickly?

If you were to buy a Seadoo 3D, you'd buy it with the 800 or the 951? I want to most fun of this machine and i've read the 800 is a little underpowered. I currently have a Sea-rayder jetboat and know what is underpowered. The boat is a fun boat but it's so long to take off, or you loose so much speed on fast turns that it is difficult to get a lot of fun from it.

Are the parts for the 951 very costly? As far as diagnosis, I can use a multimeter and I'm sure I could find the problem if the injection would fail with a good shop manual.

It's just I don't want to regret my choice and that's what makes me want the most powered one (also better fuel economy and probably more torque since the engine have quite a bigger displacement)

 

[seadoosnipe]

787cc....

Thanx for all this info seadoosnipe

I'm a week-end rider and does not live in a very humid country.

As far as reliability, except the complex injection system, is it an engine prone to blow up? Or wear quite quickly?

If you were to buy a Seadoo 3D, you'd buy it with the 800 or the 951? I want to most fun of this machine and i've read the 800 is a little underpowered. I currently have a Sea-rayder jetboat and know what is underpowered. The boat is a fun boat but it's so long to take off, or you loose so much speed on fast turns that it is difficult to get a lot of fun from it.

Are the parts for the 951 very costly? As far as diagnosis, I can use a multimeter and I'm sure I could find the problem if the injection would fail with a good shop manual.

It's just I don't want to regret my choice and that's what makes me want the most powered one (also better fuel economy and probably more torque since the engine have quite a bigger displacement)

I have the 787 in my Challenger boat and also, in my GTX. I love this little motor. With the ski, I tow my two children on a huge tube behind it. They like to fly. I'll let it lift about a foot or so.

The Challenger? It'll get about 40 mph, I feel. I've never really GPS'd it.

When you ask which one, it's really preference. I have my toys to benefit my two children. So, the additional speed and torque of the 951 is not needed. So, it's really preference. The 951 runs about 130 hp and the 787 about 110 horses.

Both the 787 and 951 are the two biggest of the Rotax motors. They have the same basic design with the exception to the 951 using reeds and the 787 using rotary.

The DI? My personal preferece would be to leave it alone. But, if you have a 951 DI that is tried and true, there is no other 951 motor that can keep up with it. The DI motor is a powerhorse.