99 SPX different carb, what jets?

[BBird]

Working on a 99 SPX 787. Starts and runs easy on the hose, revs out well. Put it in the water, and starts and idles great, did a few full throttle runs, and it screamed. Then would only rev to about 3k. Still starts and idles great, but won’t rev out past 3k. Gauges did some weird things, so looked at the rectifier, it was aftermarket and poorly wired in, so I replaced that. Still same issue, so I’m thinking time to rebuild the carbs (have cleaned and replaced, tank, pickup, vents, check valves, and filter.) When I look at the carbs the 99 came with accelerator pump carbs, and the ones on it do not have that. So my question I would like to confirm is to jet them for the 99 spec, and 99 needle screw settings and tune in from there? Also, after running for about 25 minutes in the water at 2500-3000 rpms, the battery was drained so also thinking it needs a new magneto assembly. Thanks, and for those who haven’t bought a membership, do it now! I have saved WAY more than it cost in frustration, and real dollars from this group of fantastic folks!

 

[etemplet]

Do not change your carb jetting. It is going to be different with carbs that do no utilize an accelerator pump. You said it screamed so that verifies the jetting is correct. Starting and idling fine is evidence that the low speed jetting is correct. You could have carb or fuel delivery issues. Vacuum check the fuel system, clamp each line close to the fuel baffle and pull a vacuum. If it isn't holding then you can switch to pressure and find the leak with soap bubbles. It could be the gasket on the water seperator or the fuel valve. If you have an inline fuel filter in the system, remove it.

Strange that your battery was drained but it could be a bad battery. Take your time and do one thing at a time. Good Luck.

 

[BBird]

100% of the fuel system is brand new outside of the carbs. Leak test passed with flying colors. Battery is brand new AGM also, maintained with a Battery Tender trickle charger. Will try to just clean the jets then, was hoping to do new components just to be sure. This is a keeper ski!

 

[etemplet]

If you rebuild the carbs you will eliminate them from the picture. Just use Genuine Mikuni components and read the "Carb Thread" on this forum. They can be difficult. My caution on carbs is to make sure the 3 orifices inside the barrel have good strong streams when tested. If they do not... your transition from 3k upwards will be crappy and you might not be able to get up onto the main jet. Good Luck.

 

[BBird]

I get every part I can from OSDmarine.com and have rebuilt several according to the carb rebuild thread (I have my iPad right next to where I do it, works well for me. Even though I have done it several times it is invaluable in not skipping around or forgetting something!) If you have even decent attention to detail it is relatively easy to do. The one thing that is easy to forget is checking those 3+1 holes to make sure they are clear flowing!

In general, I think I am pretty sure that you follow jet size and needle settings for the year/make of the ski and tune from there, but just want to check that thought. I also have a question about what the difference is for the same engine and carb why the different jet/needle settings. For example, I have a 92 and a 96 GTS with the 587, but they have different jet/needle settings. Just curious why the differences, maybe for another thread…

 

[etemplet]

When the accelerator pump is removed the low speed jet is replaced with a larger sized jet. The Seadoo manual is the best resource but I ofent us the ones on OSD. Just remember they are not always correct for every situation. Good Luck.