Super Jet Superjet issue

6

650sxmaschino

Location
massachusetts
Theres an issue with a 1990 superjet 650 i was thinking about buying.. it has an sbt 650 motor in it, he said it runs great when its hooked up to a hose or when the rear end is out of the water but as soon as you put it in and try to ride it dies. What could that be? He wants 600 and it looks like its in good shape in all the pictures thats all thats wrong with it.. Thanks in advance
 
Scribbleheli

Scribbleheli

Location
United States
I'm by no means an expert. But opinions I got when I had a similar problem with my js440 was that it could be a electrical ground problem.
Mine would run on land with flush kit being used. But wouldn't start on the lake.

So check all electrical connections.
The engine block AND the Ebox should be grounded to the negative batty connection.
Then you should have the Positive going from the battery to the positive connection on the ebox.
Open up the ebox. And make sure all wires are connected to where they should be.

600 for a SJ is a pretty good deal. That's what I paid. Mine was running strong. But looks ugly.
 
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M

MrBlack

Location
Upstate NY
Watch out. I had a js550 that would run out of the water but could not get it going once it was in the water. Took me forever to find the 1" hole in the bottom/side of the crankcase. (Previous owner had dropped a nut inside and the crank brought it around and punched a hole out the side.)
i'd look it over very carefully, with an inspection mirror if possible
 
Scribbleheli

Scribbleheli

Location
United States
True. But it wouldn't rev up or idle very well if I had a huge hole in it I wouldn't think. A pin hole leak could cause an issue and be hard to spot.
Post some pics of the ski!
 
Matt_E

Matt_E

steals hub caps from cars
Site Supporter
Location
at peace
I've mentioned this elsewhere. This could be caused by a number of problems, from simple fouled spat plugs, a bad coil, all the way to a destroyed topend.
 
surfjunkie

surfjunkie

Location
deland fl
if the hull and the rest is in good shape, $600 is a good deal w/o the motor. you could find a cheap donor 701 and be set.

you could probably get to the bottom of that easy. good compression?
 
JamesG

JamesG

Site Supporter
Location
Here
I had this issue and it was my carbs. Cleaned out the jets and braaap.
Coil, ehhh maybe, I usually just splash water on it when its on the hose to see if it misfires or the spark jumps.
If it was perhaps sitting for awhile; I would throw new spark plugs in, check the compression, check the carbs thoroughly and run it again and see what happens if you can.
I'd bet my left nut it's the carbs :biggrin:
 
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