Seadoo 3D Running Problems..

[anthony129]

Hi there guys I'm having some problems with my Seadoo 3D 787 RFI.

I put the ski in the water and it'll run great until i go over half throttle then it'll bog down and die, it will also not restart and run properly for half an hour.

Done all the fault finding iv founf in the threads.

No exhaust leaks.
New Plugs
Cut 5mm of the HT Leads
Cleaned out injectors and housing
Cleaned fuel filter/pump
Drained and cleaned the tank.

The only thing i have found which i am not sure upon is the voltage to the fuel pump from the MPEM..
Fuel pressure is very low it seems, but the voltage to the pump is only circa 10.5v. When iv hooked the pump upto the battery directly off 12v there is no issue with the pump pressure.

Can anyone confirm how much voltage my fuel pump should be getting.

Iv also checked all my earths and positive lead positions on the block and are good. Also removed MPEM to check for water damage but found none however left somewhere warm indoors for a few days but still the same.

Any Help Appreciated Thanks Anthony

 

[1MACGYVER]

Pull the fuel pump assembly out and check the short wiring loom (fuel pump and level sensor wires) between the fuel pump and the top cap of the assembly.
Mine was corroded in the plugs and had a bit of black wire syndrome, with a second hand replacement it runs like a dream.

 

[wrench2ride]

check your fuel pressure with it in the water and acting up, if your fuel pressure is staying steady at spec, the problem is something else!

 

[lejonet]

Did you solve this? I have the same issue..

 

[Sportster-2001-951C-Stock]

Yes, the first thing you guys who have injected skis need to do when you experience this symptom is to check fuel pressure while duplicating the conditions.

 

[Coastiejoe]

Fuel pressure is crucial. Most think it is fine as they know it is pumping. The reality is, it has to have high pressure and volume for the system to work properly.

 

[lejonet]

Thanks for your answers.
How do I check the fuelpressure?
The machine worked perfectly for fiften minutes then it suddenly started to loose throttle/power.
The loss of power was over 5 minutes until it stopped.

 

[Sportster-2001-951C-Stock]

You will need a pressure test gauge and the appropriate fitting(s) to attach. The entire procedure is described in the Bombardier shop service manual for each particular model of ski.

These manuals are written quite well and contain a wealth of information, anyone who will work on their ski should obtain the factory manual for their ski:

http://www.seadooforum.com/manuals.php

 

[wrench2ride]

As previous replies stated fuel pressure is very critical, testing it on the trailer is not good enough unless you can get it to act up on the trailer, fuel pressure test must be verified when it is loosing power. like sportster said, a shop manual is probably the most valuable tool you can have!

 

[lejonet]

Found the problem. The piston in the front cylinder was broken.

 

[Coastiejoe]

That would do it.

I'm thinking compression tests should be one of the beginning stages of diagnostics.

 

[wrench2ride]

that would have had a fair bit of piston slap when running and especially when shutting off, be sure to pull it down to the crank and clean out debris and check crank bearings, rods, rotary valve shaft and gear, ect.

 

[griz400]

lejonet, please make your own thread, this is anthony129 thread, you should have 12volts or should i say battery voltage with just the lanyard plugged in, then with it running, it will be whatever your charging system is delivering to the battery -- over 13.0 volts, this is why a proper charging system is crucial to an rfi ski , this is why these skis dont run right when they have a bad rectifier,
Basic fuel system operation -- RFI motors have 5 sensors that provide information to the fuel injection system. 1) throttle position sensor. 2) water temp. 3) air temp. 4) air pressure. 5) crankshaft position sensor. If one of these sensors malfunctions the watercraft will be put into limp mode and will be rev-limited to get the operator back to land.
RFI fuel systems. The fuel system consists of .1) the fuel pump. 2) the fuel pressure regulator. 3) the fuel filter. 4) the fuel level sensor. 5) the fuel injector. Every thing listed here except the fuel injector is located in the fuel pump assembly which is located in the fuel tank. Fuel pressure should be tested while the watercraft is under a load, due to the fact that the fuel pressure can change drastically from just checking it at idle. The correct fuel pressure should be 56-60 psi.