The RFI (Rotax Fuel Injection ) Spot

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Hi Jeff,
I completed the rebuild and install of my 98 RFI last week. OnFriday I did a hose test and it fired up on the 1st push of the Start button. I ran it breifly to inspect the gaskets, etc. - looked fine. Took it to the lake on Saturday and folllowing your break-in procedure above, I ran at 20% throttle varying down for about 25 minutes (ran well) then headed to the dock for a 30 minute break and inspection.
I went back out to increase the throttle rate to 50% and it ran well for about 15 minutes and began to bog down and I would not accept throttle. I limped to shore and decided to pack up due to time.
I plan to test the rectifier tomorrow - I believe it's the original. To test, I plan to attach hose and rev engine to 3500 rpm and test the battery to see if it jumps above 15 volts. Am I on the right track?
PS - in addition to the rebuild I drained the fuel, pulled and inspected the fuel pump, replaced fuel injectors with new ones fron Five O.
Thanks, ROb
 
firts test your battery without ski running, should be like 12.5 or better -- then start and run at approx 3000 rpms with meter attached to battery, and make sure its around 13.3 - 13.7 or so, this tells you its charging ok, make sure it doesnt go up like 14.5 - 15.0 cause thats like a rectifier, when my ski is not in use, i use a 1.5 amp battery maintainer and leave it hooked up and i leave battery hooked up -- i just make sure i dont start it with battery hooked up to maintainer --- its just a cheap maintainer from walmart, but i have never had an issue with it -- like 25.00 .....http://www.walmart.com/ip/Schumache...1b4954557236&bucket_id=000&findingMethod=p13n

cause you know these rfi's are touchy when it comes to voltage cause it take voltage to work 5 sensors, and 2 fuel injectors , fuel pump, etc, ....... carbed skis dont have all this voltage concerns ...
 
Jeff - I was away this weekend and did not have a chance to conduct the test but plan to later this week. I do plan to purchase a spare rectifier and see that OSD is out off stock on them and they don't know when they might have more. Any suggstions on an alternative? I 've seen afternmarket rectifers but I am leary on puchasing. Thanks, Rob
 
Well I finally got around to testing the rectifier last weekend - tested battery at 3k rpm and it came in at 13.7. Based on the results it shows that the ski is charging ok. On the hose the engine seemed to run fine - but we all know it's a different story under load. Again, the ski bogged while on the 1st run (a few weeks back) after the rebuild. Ran well at 20% throttle for 25 minutes then I let it cool down for 30 minutes before I went back out to run at 50%. It ran well for about 10 minutes then developed a bog - no high-end rpm. I changed the plugs before the above test - the new ones on the 1st run were somewhat fouled.
I plan to head out Saturday since the weather is pushing 90 in Raleigh to see how it runs. Any suggestions for things to look for if it develops a bog?
 
where would be the best place to buy a new rectifier for a 99 rfi? i would really like to buy a good new one instead of a good used one
 
the gsx rfi i just bought, for some dumb reason the PO premixed the gas / oil which i am going to flush out before installing a new rebuilt motor,
i know the premix can kill injectors but can it harm the fuel pump and pressure regulator? thanks.
 
I had one of these that "lamajama" mentions and it lasted 1 season. Went back to a factory one, no problems for the past 2 seasons. May have just gotten a bad one. Not trying to bash anyone, just my experience.
 
Dugout said:
I had one of these that "lamajama" mentions and it lasted 1 season. Went back to a factory one, no problems for the past 2 seasons. May have just gotten a bad one. Not trying to bash anyone, just my experience.
Click to expand...

Yep - who knows with electronics? I replaced one in my wife's DI with an OEM (before I heard of the one I linked to) a year ago and
it's been fine. The 4-tec one I changed on my own in May and it's been fine too. That's about the best you can say for electronics!

They work until they don't..and they can stop at any time.
 
jammin777 said:
the gsx rfi i just bought, for some dumb reason the PO premixed the gas / oil which i am going to flush out before installing a new rebuilt motor,
i know the premix can kill injectors but can it harm the fuel pump and pressure regulator? thanks.
Click to expand...

you HAVE TO USE AN OIL INJECTION PUMP ON AN RFI .... premix is no good at all, oil and air comes in on one side of engine, fuel on the other, you probably didnt hurt the pump, but i would change the screens, also clean the injector rail out, you have it all apart anyways .....
 
PGHMAN said:
Well I finally got around to testing the rectifier last weekend - tested battery at 3k rpm and it came in at 13.7. Based on the results it shows that the ski is charging ok. On the hose the engine seemed to run fine - but we all know it's a different story under load. Again, the ski bogged while on the 1st run (a few weeks back) after the rebuild. Ran well at 20% throttle for 25 minutes then I let it cool down for 30 minutes before I went back out to run at 50%. It ran well for about 10 minutes then developed a bog - no high-end rpm. I changed the plugs before the above test - the new ones on the 1st run were somewhat fouled.
I plan to head out Saturday since the weather is pushing 90 in Raleigh to see how it runs. Any suggestions for things to look for if it develops a bog?
Click to expand...

replace spark plugs, and set oil pump on the "slots" , use full synthetic oil, and no premix, also -- retest compression -- only takes a minute, this way you know its all breaking in good ...
 
thanks griz, yes i am aware of not premixing RFI's and the oil injection is in tact. it was the po that screwed things up and I'm a fixin lol!
i will be taking the gas tank out and flushing and cleaning the filter screens and having the injectors rebuild as well. thanks again!
 
i lost 2 motors till i replaced injectors, one was sticking open and would wash cylinder down and man, that cylinder and piston was real ugly ... the choice is yours though ... but, thats what was wrong with mine, but now, i have been trouble free for over 1 1/2 yrs, if yours are factory injectors, they are goin on 14 yrs old, and you said there was premix though em ...
 
ok well i definitely don't want to damage my new motor soo i will see if i can cross the part numbers to bosh automotive ones as i am an under car auto mechanic and can get them at cost. i think i read somewhere that they would cross over. besides those injectors a a real pain to get to!
 
Last edited by a moderator:
jammin777 said:
ok well i definitely don't want to damage my new motor soo i will see if i can cross the part numbers to bosh automotive ones as i am an under car auto mechanic and can get them at cost. i think i read somewhere that they would cross over. besides those injectors a a real pain to get to!
Click to expand...


i can pull injector rail out of mine in like 10 minutes, only 2 10 mm bolts and disconnect fuel line ...

take the number of the top of the injector -- its a bosch number
 
i got big hands and arms lol! and im sure the gsx is tighter than a gtx lol . getting it apart isnt so bad but putting it together. all by feel.
i need a mirror.
i have a bore scope but seems useless! yep will write the bosch numbers down tonight. thanks again griz.
 
I bought a 2000 GTX RFI and the fuel pump was bypassed from the computer with an on/off switch in the storage compartment under the steering wheel. The previous owner did not know why. After failing to shut off the switch and draining the battery a couple of times, I rewired it back to original. Now when I plug in the DESS, the fuel pump kicks on for about a second and shuts off. Any suggestions?
 
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