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base Carb setting for 96 GTX 787

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Paul 1996

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HI All,

Can anyone advise what the jet setting should be on my 96 787. Im running 40:1 premix with Seadoo XPS. I have been told the screwdriver adjustable jets on the top of the carbs should be wound fully in ( these normally have a factory seal that has been removed at some stage ) and what setting the T handle jets should be. I have replaced the seals on the top end, and pulled the carbs apart for inspection, so not a rebuild.
 
In a little more detail, the Low speed screw, has the pin through it and actually should be set at a standard setting of " 1 1/2 "Turns. The high speed screw has a plastic cover on it. It should be adjust to "0", or all the way in. The Plastic cover over the high speed screw allows the high speed screw to be adjust out only up to 1/4 turn extra if needed. Be sure while your at the carbs, to adjust the linkage so the carbs are in full sync with each other. The throttle cable should be adjust too, so it gets full throttle and snaps closed for idle position.

Karl
 
My book calls for LSA setting of 3/4 to 1-1/4 turns out.

I have had much better luck with settings closer to 3/4, but it is always better to start out on the richer side and work leaner, rather than the other way around.

1-1/2 has always been WAY too rich for me on both my twin carbed 787s.
 
Hi guys im new to this, so tell me to get the low speed adjuster to the 1 1/4 where its supposed to be do i just screw it all the way in and back it off 1 1/4? Also the low speed adjuster it the one with the pin lookin thing that goes through it, correct?
 
Mook_c1 said:
Hi guys im new to this, so tell me to get the low speed adjuster to the 1 1/4 where its supposed to be do i just screw it all the way in and back it off 1 1/4? Also the low speed adjuster it the one with the pin lookin thing that goes through it, correct?
Click to expand...

Low speed adjuster should be turned in until it feels reasonably snug, then back it out 1 1/4 turns. Set high speed in all the way. As stated previoulsy it is better to set a little rich to start with. I would highly recommend that you read the sticky at the beginning of this forum.
 
I noticed you said you were running SeaDoo XPS oil. The recommended oil for that enginge is XPS Synthetic. I would consider running Synthetic oil if I were you.
 
High speed adjuster

Ok so for the high speed ajuster i should literally just screw it all the way in? Also what should the ski idle at when its just on the hose?
 
Yes, screw the high speed adjuster all the way in. Recommended idle speed while on the hose is approx 3000 rpm. There is an idle adj screw on the mag carb. Do not use the lsa to adjust the idle speed. Also, it is recommended that you start the engine before turning the hose on. One of the plastic shut off valves that goes on the end of the hose comes in handy for this.
 
Ok, becaus this is where im at, i bought the ski it was runin great for about a hour in a half then all of a sudden i lost rpms and speed and it prigressivley got worse from there, i did some reading and replaced all the gray lines and soaked amd cleaned the carbs the back carb micro filter was veryy dirty with both carbs cleaned i reassembled and also cleaned raves they were dirty also put it all together and it idled im thinken i need to turn the idle down however when you punched the gas it wont respond i think its running too rich now that its getting the proper gas what would you say?
 
From what I can deduce from this thread it sounds like you could be running to lean. I would suggest that you get it in the water under normal operating conditions and see where you are at. Set the idle speed in the water at about 1500 rpm. When you get it where you can do an engine kill on the engine, you will need to do that and then pull the plugs and read them. Be sure to take extra plugs with you. This is a pain to have to do but is the only way to really tell what each cylinder is doing. Have you read the compression? If so what was it reading.
 
Compression is 140 in each i also should say when its on the hose and you hit higher rpms u can see a hint of the blue oil in the smoke alsowhen i do take it to the lake when i check the plugs what am i looking for?
 
That depends on some other factors such as pump and wear ring and water condtion. I would think, everything being in good shape, that you should be able to see something in the 60's if you are riding it alone.
 
Ok, tts what i though, back to the mixture thing, nit trying to argue but i cant think how it could be runin lean considering when its on the hose at idle and you try to punch it it bogs but if you milk it you can reach high rpm it seems to me it might be running to rich? Like i said not arguing just trying to figure the ski out...
 
At the point you are at you need to get the unit into the water and do an actual operational analysis. Reading the plugs will tell you a lot. Traditionally when you throw a load on an engine an it hesitates, the mixture is to lean. I guess maybe someone else could chime in on this and give you some additional advice.
 
Hi again guys, so today after work i will be putting a exhaust manifold gasket on amd rave valve gaskets, besides the thread licker in the bolts is there any other sealent i could put on the gasket to he
lp the seal?
 
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