96 SPI Turns Over But Won't Start Mystery

[Seadoo Tuner]

First start attempt for this year, has run fine the last 4 years except for the odd hot start issue a couple of times after running all day last year.

Plugs are wet so has fuel, has compression, has spark. Tried to start and turned over but wouldn't fire up. Switched to Reserve and fired up for a second, then no more after many multiple times trying on reserve and regular tank setting (choke on and off). Poured fuel in cyclinders and down carb throat and still not firing up.
Just cleaned and rebuilt the carb with genuine mikuni kit, pops off at 27psi every time, no leaks, carb is golden. Not sure what to look at next.

 

[Seadoo Tuner]

Worked on the SPI tonight, compression tested again and both cylinders are 140psi. Spark plugs are wet so gas is getting to the engine. Quarter tank of no ethanol fuel. Both spark plugs have correct gap and strong spark and battery was fully charged. It will turn over all day but not fire even for a second.

 

[tobytd]

New needle & seat?

 

[SIMPLEARKANSAN]

Does the engine have a rotary valve? If so I’m thinking the brass gear on the rotary valve is stripped. Search for that condition on YouTube or google. You will usually have gas blow back out of the carbs too

 

[Seadoo Tuner]

New needle & seat?

New 4 years ago, looks like new when I rebuilt the carb last week.

 

[Seadoo Tuner]

Does the engine have a rotary valve? If so I’m thinking the brass gear on the rotary valve is stripped. Search for that condition on YouTube or google. You will usually have gas blow back out of the carbs too

Yes on the rotary valve.
Looked up the brass gear, will try to borrow a inspection cam as I saw you can put it down the carb throat and check if the valve is turning, which in turn means a good brass gear apparently? Any other way to check if the brass gear is sheared?

 

[SIMPLEARKANSAN]

So it can be sheared and still turn. If it’s sheared really bad you may mot get any movement. I’d try the scope down throat of carb first and if that doesn’t work, then I’d pull carbs and the rotary valve cover

 

[Seadoo Tuner]

When you pull the rotary cover, can you re-use the gasket? Also heard that when you pull the cover to make sure something doesn't come off with it (rotary valve?) so you don't have to redo timing?

 

[TheGTIjetguy]

The rotary valve cover most likely uses an o-ring. I wouldn’t reuse it myself but I suppose you could if it looks good. The valve itself looks like 3/4 of a pizza cutter wheel and is on a fairly long splined shaft, so you shouldn’t have any problems leaving it be. It will need to be retimed if you don’t match-mark it and decide to remove for some reason.
Are you sure it isn’t flooded? You mentioned wet plugs. You can try cranking without the plugs in for a bit to clear it out.

 

[Seadoo Tuner]

Cranked without the plugs a few times, choke on, throttle held on full, and she ran a second. Then tried again with choke off and she fired and ran. Started and ran multiple times, woo hoo! Thanks all for your help.

 

[TheGTIjetguy]

Glad to hear it. Enjoy the water this season.