93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

[moonbuggy]

It started at WOT, a little burble and slight loss of top speed. I'd ease back on the throt a little and things were fine for awhile. Then I had to run about 3/4 to keep an odd hesitation out of it (seemed like fuel starve out). Then the random shut downs and gauge gremlins. Now it starts easily, seems to run good, SMOKES like a chimney and won't get on step.

replaced: plugs, fuel pump/filter/lines and ignition switch
cleaned: fuel pick-up, check valve, carbs/bowls, batt terms and connects

eng. ser. OEO30788
black stator
good comp. on all 3 cyl.
batt. 13.7 dcv
bright blue spark at all 3 plugs
no errant current jumping around coils

ohm meter at rx1000 scale readings:
disconnected red/blue wire

stator- red to blue = 1100
red to ground = 0

trigg- purple = 1100
white = 1100
brown = 1100
what to do next? local shop say's it can't be tested out of water and charges 65 bucks each time he needs to take it down to river for testing. dude's playing with a full deck a JOKERS!

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

After chasing alot of threads about simular probs, I've found the readings on the stator as "failed". So I'm pulling the flywheel in anticipation of a "red stator" swap. Unsure of which part # for the 93' 90hp sport jet. Also do I need more than the "RS" and adapter.... or??

 

[kend301]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Yes your stator is bad , I will comfirm the readings and that you used the correct test procedure tonight and post up what you need to get the red stator working on your setup ..

 

[kend301]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Yes you did the tests right and your stator is bad . You have the old ring type connectors ,Lots of stuff needs to be updated . You could go with a direct aftermarket replacement that works with what you have or upgrade to red stator or even a complete CDM convirsion kit . before i recomend a solution have you gotten the flywheel off and how do the magnets look ? BTW your flywheel pulling method scares me to death !!

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Thanks for the reply. I haven't popped the FW off yet, maybe tonite, I need one more bolt for my puller. I'll post the FW info as soon as that happens. The previous owner had replaced the switch box in 2002 and this is the first prob with it since. I take it out 4-5 x's a week during steelhead season and take it to the ocean a few times a year, so the fix needs to be reliable. I'm really looking forward to getting him fixed and maybe help some others that may have simular issues.
As for my FW removal tech...... the chain and strap are only used to keep the FW from turning during lock-nut removal, much easier than trying to keep it from turning using a bar or ?????
Thanks in advance for your willingness to assist!!!!

 

[kend301]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Gonna do some research on a stator that CDI has available , I run lots of stuff from them on my boat . I knew one person who got one and stopped keeping in touch after 1 seeason with it on but is a direct replacement for the black stator , nothing else needed. As clean as your engine looks this might be the way to go for you and I also have the pn for the CDI ring type switchbox .

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

SaaaaWeet, I'm off today so I'll give the Flywheel a go and post that info asap. It sounds as if the AM direct replacement stator would be the ticket to ride.
Just a note for people: This boat ran good, went fast(47.9mph-GPS) and started easily with a failing stator. First just a little extra smoke at low rpms and didn't run well at WOT. It gradually got worse over months until it wouldn't get on step. All indicators pointed to fuel starve out (according to boat shop). Does your boat run well on the trailer but won't get on step? Probably not the ride plate or Imp. either, reason? I caved the RP and Grate on a rock at full throt one nite running back up river to the ramp. Went four miles with it and the seal sticking down about three inches at the front edge. Was still running at 36.4mph on step. I just stomped it out and am still running it 2yrs later at 42.4mph (before stator failure). The short of the long? Get an OHM meter and do some testing.:facepalm:

 

[kend301]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Yes the AM stator is the way to go for you , I need to know if your stator pn is 8778a10 or 9873a24 this makes a huge differance !!! I have to know to get the right part numbers !!!

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

I just got the flywheel popped; one 17 dollar auto-z peace sign puller, some love taps with big hammer, one flywheel in hand- Priceless. some PB'laster doesn't hurt neither.
So the magnets appear to be in good shape and securely attached (what do I know). What else should I be looking for on the FW?
The key-way on the crank looked good, it had some rust but cleaned-up nicely. Same story with the FW and the key. So I'm thinking...... replace the Key itself...??

Stator num. 398 9873A24

thanx!

 

[kend301]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

OK you need CDI part number 174-9710k1 for the stator , should be available at the store on this forum , I would also replace the trigger as it looks like it got very hot because the acrylic top has peeled up towards the center , the CDI replacement is 134-9021-3 , I would really recommend replacing it I have seen them OHM ok and still be bad . If you want more info on CDI parts go to www.cdielectronics.com and choose mercury the 90 hp 3 cyl , 1993 , you can see the parts and look at the install sheets from there ...

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Nice!!- Thanx Kend301
I'm super "jazzed" to get him back out there. So replace the trigger too.......hmmmm, probably ought to (I may post a close-up of it). Did anything else jump out at you? What are your thoughts on the Key, it had a lot of rust on it and was stuck in the FW keyway? Also where would I get one.

Added trigger photos
note: 1st one with stator on, the rest with stator off.

 

[kend301]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

I would replace the trigger for 3 reasons , the top has signs of heat because it is peeling up , it is not something you can fix out on the lake long enough to get back in and I have seen them test good cold and bad hot .... save yourself lots of potential fustration for a hundred bucks .
Flywheel key should be fine , just clean it up and chack for any real bad wear spots if none reuse it . I would spray some wd40 on the top of the crank area where it is rusted and wipe it clean as best as you can.
I must say 2 things first of all your engine is very clean and in excellent shape , makes me jellous looking at the pictures . Second you have the first run of the sport jet engine when stuff worked before they went to nightmare parts combinations . keep it as stock as possiable !
Post up if you need anything , sorry it took so long , computer crashed and had to breathe life back into an old dell to get back on line .

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

So the stator and trigger have been ordered and should be here in a couple days. ITMT I'm cleaning the flywheel and key as well as the entire engine compartment. Thanks for the compliments and will do, i like "dependable".
Totally understand, crashing sucks, just went thru it with our modem. Thanks for all the help and will post up w/picts as soon as parts are in.

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Replaced stator,trigger and rect/reg. Now it runs awesome but takes 10-15 sec.'s to get on step, wooooon't spool-up and top speed is in low 30's. what the.........? CDI says "rotate Stator one mounting hole".......?? Which direction......??? Blow it up.........???? what will happen on the next episode of "SPORTJET 90"

Posted some photos:
CDI Trigger #134-7029-3
CDI Stator #174-9710K1
Sierra Rect/Reg #18-5744
"red" Loc-Tite; on all mounting bolts
Dielectric grease; in/on all connectors and back of Rectifier
bearing grease (to hold Key in keyway during Flywheel install)

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Took it out and tested again. Still not right. It got a better hole shot after adjusting the trigger timing some. I did try rotating the stator one hole in both directions.....it ran but would die as soon as i throttled up:facepalm:. ITMT, I'm going thru the carbs again just cause I can't find anthing else to do. It just doesn't have the max RPMs it should and takes 10 sec. to get on step. What to look at next (tired of lookin, need to be cruisin')???

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Went thru carbs again, they were clean, now they're really shiney too. So I don't think that's the issue.
Ran across a thread that talked about the Rev Limiter. Sooooooooooooo, I thought I'd try testing with it disconnected. Going to the river soon (crossed fingers)! Will it blow up? Do you think it will bob like a cork all the way to the ocean if it "accidently" comes untied from the dock or could it be that we find the FIX.......stay tuned.

 

[moonbuggy]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Check it - disconnected the Rev limiter and took him for a test. It got on step almost immediately and topped out at 38.7 mph. I then "eyeballed" the timing back to a less radical setting and posted a 40.9 mph. So I'm still not getting quite the max rpm/speed, but it's much better, at least I could run the big Breaks on the river. I'll get the timing set proper and hope to find a new Rev. Limiter to install, then we'll see about getting back 45+.

 

[kend301]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Great to hear , thought you had already covered the rev limiter , but the bad stator probably burned it out , common for voltage feedback to fry stuff on these things , Glad you got it going !!

 

[jmff38]

Re: 93 Jazz w/90hp Sport Jet- gradual power loss and intermittent shut down

Great thread guys!

I have a couple questions for you all (have a 94 sport jet). Were those the pics of the ride plate before or after you bent it back into shape? Just asking cause I'm trying to determine if mine needs to be worked on. It is not perfectly flush w/ the hull, but everything looks good around it. I don't see any obvious problems w/ it, but I just bought the boat a couple weeks ago and am not yet happy w/ top speed (max 31) and getting out of the hole and on plane. My manual says I have to discard the screws from the ride plate and buy new ones if I remove it. True or can I but some loctite on them and go?

I also am wondering if I have need to check out the rev limiter. I need to get a tach to see where my rpm's are at.

Thanks in advance!