94/95 sport jet 90 issue

Thesmanman

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Hi, I'm new here and not sure if I'm posting this thread in the correct forum. My apologies if I did it wrong??

I just purchased a 16' Dynasty Jet Storm for $400 including the trailer. Boat and trailer are in excellent shape inside and out. Looks like it was stored in a garage for many years. Here's the down side...

Engine (Sport Jet 90) turns over fine with good compression, but no spark on any of the 3 cylinders. What can I do to trouble shoot it?
Where should I begin? How too's would be great. Ive never owed a sport jet engine before.
Also, if and when I get it going,.how would I go about running it out of the water? I see no flush fitting.
Oh and when I move the forward/reverse control the linkage on the carburetors don't move, but the gate/flap on the drive moves up and down as it should.
Any help would be greatly appreciated.
Thank you,

John
 

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alldodge

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Could use a serial number to narrow your motor down, but the sport jet is basically and outboard with a jet pump attached to it. This should be in the PWC section but will see if southkogs might move it there.

Here is the section for the jets, and once the serial number is know it can can deeper for parts
https://www.mercruiserparts.com/parts-for-mercury-sport-jet

Here is a good thread for reading
https://forums.iboats.com/forum/gen...2110-no-spark-sea-rayder-mercury-sport-jet-90

If Jeff Walkowiak is still around he would be a great resource
 

Thesmanman

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Could use a serial number to narrow your motor down, but the sport jet is basically and outboard with a jet pump attached to it. This should be in the PWC section but will see if southkogs might move it there.

Here is the section for the jets, and once the serial number is know it can can deeper for parts
https://www.mercruiserparts.com/parts-for-mercury-sport-jet

Here is a good thread for reading
https://forums.iboats.com/forum/gen...2110-no-spark-sea-rayder-mercury-sport-jet-90

If Jeff Walkowiak is still around he would be a great resource

Thank you very much! Here is the serial # 0E090045
 

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Thesmanman

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Good to know. Thank you. Ok when I went to site link you posted, it does have the flush kit in it already. So that’s one down. Now on to the no spark issue!!
 

Thesmanman

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Among the no spark issue. When I figure that out and get it running, is there a way to test the oil injection if it’s working or not. Can this engine run on premixed fuel if the oil injection doesn’t work?
Thank you,

john
 

alldodge

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As in previous post its best to fix the spark issue by replacing everything. According to Jeff in the previous link and this one
https://jetboaters.net/threads/sportjet-120-ignition.12682/

Its best to do this or if only the brain is replaced it will start and run maybe one time, and then the brain will burn out again

The oil injection can be disabled and just run premix. The oil injection changes the amount of oil from about 90:1 at idle to 50:1 at WOT. Changing to premix of 50:1 makes it smoke at idle and clean at WOT, just like the other old 2 strokes
 

Thesmanman

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Thank you AllDodge. I’ve read both threads and must be missing something because I can’t seem to find the link to the complete ignition system to replace it.

The other question is how would I tell if it’s already been replace? What can I look for to tell if it’s the new ignition system, since I do see the flush upgrade on the engine. Maybe the PO already did the ignition upgrage. How can I tell if it was done?
Thank you,

John
 

alldodge

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I found Mark on Jetboats dot com and sent him a message to see if he could have a look here.

I'm trying to help, but don't do much work on 2 cycles. My last one lost spark (2001 seadoo DI) and found how to troubleshoot. Mine was the rectifier. Need some OB folks maybe like jerryjerry05 or others to assist

What I'm getting from Mark's post is, its a Force system and if it goes bad you need to replace everything. So that would tell me is first look at the stator/flywheel and see if its been damaged. If all good, then may need the the trigger and other items.
 

alldodge

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Contacted Jeff and he is saying "paraphrasing" he is tired of seeing the spotjet because there are a bad design and parts are hard to find. There just not worth the trouble.

Wish I had some better info
 

alldodge

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Have another response from Mark

I am sure the rectifier went bad and blew the brain if he replaces the rectifier with a p w c voltage regulator as I posted and gets a new brain it should be ok then he should sell it fast and get a boat that is still in production the old force outboard engines all had that problem and force is who made that engine from an outboard engine.​
 

Thesmanman

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Thank you for all the help. I am going to sell it,...hopefully!!
Its a shame, the boat and trailer are in very nice shape.
 

alldodge

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Don't know what it would take (I have no clue) but wonder what it would take t replace the motor with like a Seadoo or Waverunner power plant?

In any case its probably best
 

Thesmanman

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Would anyone know how to tell if my SJ90 has been converted to CDM ignition? What can I look for and would anyone have the wiring diagram for the CDM ignition system. Or by 1995 was it upgraded already from the factory?

Thank you
 
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H20Rat

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Don't know what it would take (I have no clue) but wonder what it would take t replace the motor with like a Seadoo or Waverunner power plant?

In any case its probably best


Unless you were really, really good at fiberglassing, there is no way to convert it. Almost every other jet craft in existence uses a horizontal mounted engine. The sportjets are outboards with a jet drive on the bottom, so you can't adapt a different engine. Even force engines of that identical year/horsepower used a different crank, so a like for like powerhead swap isn't going to happen.

What COULD be done with a proper machine shop is an adapter that would convert a newer outboard to fit on the input shaft of the stock jet housing. Wouldn't expect easy or cheap, but doable.
 
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