Sport Jet 90 died on the water! Help!

[JW-JetBoat]

Help guys, (Kend301) !!

I was on the water for a few hours. The boat was running without issue, started off and on a few times resting back at the dock then I'm out on the water full throttle hitting big waves, and I throttle down and the engine quietly shuts off.

I figured perhaps the engine got flooded from the big wave movement and throttling down so quickly, would you all agree?

I wasn't able to get it to start after several attempts and time, and eventually had to get it towed.

I thought I also killed the batt trying to turn it over so many times, as it got to a point I could no longer turn the fly wheel fast enough for a full rotation. I got the battery tested and charged and it's not the battery apparently. The boat still won't turn over fully it struggles to turn over just like a boat with a dead battery would do.

Any ideas? Could the starter itself be messed up from too much use?

 

[JW-JetBoat]

Re: Sport Jet 90 died on the water! Help!

Anyone!?

 

[My_Jet90]

Re: Sport Jet 90 died on the water! Help!

You might have worn out the starter. Try removing the plugs. With them out it should be a lot easier to turn over. Plus then you can test to see that you still have spark. Mine died on the water the same way and I thought it was fuel pump. Turned out no spark and I'm still trying to get that going. I've now got spark back on #2 and #3 after new trigger and CDI box.

Good luck these things are known for electrical issues.

 

[kend301]

Re: Sport Jet 90 died on the water! Help!

As far as the starter I think it has burned out , follow the above advice and pull the plugs and then check cranking speed / ability . Once you have the starter issue resloved , begin by checking spark

 

[JW-JetBoat]

Re: Sport Jet 90 died on the water! Help!

Thanks guys, I ordered a new starter for $115 as soon as it comes in I'll throw it on and then test spark as well.

 

[JW-JetBoat]

Re: Sport Jet 90 died on the water! Help!

Hi guys, just a sad update here..

Got the starter, and I also replaced the spark plugs with new ones. The old ones were covered in grime and very black. The engine still won't start. It turns over fine now with the new starter but no ignition.

The spark I think is very weak, it was day light out but I found it hard to see the spark on the plugs if at all when looking at them. I was holding the plug at the time and felt it was getting electricity, perhaps not enough.

Does this sound like a switch box? Any other suggestions? It looks like it'll be grounded for the rest of the season..

 

[My_Jet90]

Re: Sport Jet 90 died on the water! Help!

From my (limited) experience in testing and reading forms...No it is not the switchbox. That part either works or does not work.

Did you check the spark at night and have a good ground going to it? You can make an easy ground by using house 14 guage wire and wrapping it around the plug(s) and then to a good ground.

If you have spark...then I would start looking at gas and compression.


IMHO.

 

[dice_left]

Re: Sport Jet 90 died on the water! Help!

if you do a google search for mercury marine you should come to a site where you can download free tech manual on ignition parts. than you know what to and how test all electronics. I hope this helps

 

[JW-JetBoat]

Re: Sport Jet 90 died on the water! Help!

Hi guys.. I wasn't able to find that manual by the google search can you provide a link.

I'm not sure what is going on right now, the gas seems to be pumped into the system, and I'm getting spark in some form, but no starting...

 

[boerdoc1]

Re: Sport Jet 90 died on the water! Help!

http://motorka.org/doc/mercury/service_manual/jet/SJ90_120_95xr_125xr_831996r1/cover.pdf


That is the manual I used.
Kent

 

[kend301]

Re: Sport Jet 90 died on the water! Help!

That is the best I have seen online but just be aware on the 95 CDI motors the diag info on the stator is wrong if you have updated to the RED stator .

 

[JW-JetBoat]

Re: Sport Jet 90 died on the water! Help!

UPDATE!

Well it looks like I might be out on the water once again. I got it up and running again. This boat is strange, when you prime the engine it needs about 30 minutes if it hasn't been used in more than a day for the engine to start. I feel it has something to do with how the carbs work.

Anyways, new starter, new plugs, and it's working. Just have to give it a few pumps of gas before I get on the road to go boating and then I should be good. I may get it out on the water one more time this year!

I'm thinking about selling it and getting a bigger bowrider next year maybe....

 

[JW-JetBoat]

Re: Sport Jet 90 died on the water! Help!

http://motorka.org/doc/mercury/service_manual/jet/SJ90_120_95xr_125xr_831996r1/cover.pdf


That is the manual I used.
Kent

This is a great manual, thank you as well!

 

[kend301]

Re: Sport Jet 90 died on the water! Help!

Your carb vents are clogged , you are flooding the motor that is why it takes 30 min to start , pull the carbs and clean them , pay special attention to the fittings that have the clear tubes on the throttle linkage side .