96 SPX idle and top end is good but bogging off of idle

[braindontstop31]

Hello all, This is my first post here!! looking for some advice

Just rebuilt carbs, took to lake last night and the ski idles fine. But when you
try and nail it and go wide open it just boggs. If I slightly pull the choke and feather the gas I can get it to go wide open and it does fine and I can run it wide open all day then when I let off the throttle and return to an idle the same happens, idles fine but boggs when trying to go back to higher throttle. Before I rebuilt the carbs the popoff was about 55psi. When I rebuilt the carbs I replaced the Needle and seat with new ones (1.2 as same as original). I tried using the original springs but my popoff was only about 25 psi so I used the silver longer springs in the rebuild kit to get the 50psi popoff. I am thinking this is where I should start by maybe replacing the springs with the original. What do you guys think.

already tried new plugs, unplugged the red wire on the rectifier--same
replaced grey lines, cleaned the fuel switch, baffle, filter before carb rebuild

 

[Dr Honda]

If you used the old springs, and your pop-off went from 55 to 25... then you put in a 2.0 needle and seat. AND... in that case... it would do exactly what you are describing. As soon as the vacuum drops, you can no longer hold the needle open, and you run out of fuel. Pulling the choke will re-fill the carbs... and once you get up to higher RPM's, you have enough vac to hold it open once again.

I would double check the seat number.

 

[braindontstop31]

both the original and the new seats had 1.2 stamped on them

 

[braindontstop31]

I used the #2 kit for seadoosource, the needle and seats are aftermarket and not Mikuni

http://www.seadoosource.com/carbpkgs.html

 

[Dr Honda]

OK... then the hole in them is wrong. Right from Mikuni's chart... 95g spring and a 2.0 will be 25 PSI, and a 1.2 with a 95g will be 55 psi. Also... you would not see a big jump in the pop-off pressure if all the parts were the same. I would expect maybe a 2 or 3 psi difference.


One thing... where they OEM or aftermarket needle and seats?

Regardless... the carbs need to come apart again.

 

[Dr Honda]

I used the #2 kit for seadoosource, the needle and seats are aftermarket and not Mikuni

http://www.seadoosource.com/carbpkgs.html

He used to be good about using OEM parts... but his seats are aftermarket. Something is up with them. Either the depth is off... or the hole is wrong.

 

[braindontstop31]

I noticed the profile of the needle was different at the very tip, the original was to a point and the aftermarkets are a little more blunt.

Do you think I should just put my old needle, seats and springs back in? what could really go wrong with them anyway?

 

[Dr Honda]

Did you have the bogging issue before the rebuild? If not... put them back in.

The needle and seats can live a long time. As long as they aren't leaking (will show as a hard, hot restart) then they were probably OK. Also, set the pop-off to the bottom end of spec. (96 SPX 36-60 psi)

 

[braindontstop31]

Before I rebuilt them it would not hold high rpm from fuel starvation. I found the usual the filters inside
were clogged up. I just decided to go ahead and rebuild them while I had them out. Also it was never hard to
start cold or hot. So I quess my old n.s. are probably okay.

 

[Dr Honda]

... it was never hard to
start cold or hot. So I quess my old n.s. are probably okay.

yep. they probably were.

 

[braindontstop31]

I will go ahead and tear them back down and stick my original needles, seats and springs and see what she does.
Thanks for your help.

 

[braindontstop31]

where is good place to buy original Mikuni needles and seats

 

[braindontstop31]

Dr. Honda, you were right on the money. I replaced my aftermarket needle and seat with my originals and put back in my springs. Tested the popoff on both carbs around 50-53psi. Took to the lake and wala ran like a top. No hesitate in the mid range at all ran awesome. You were spot on. Thanks!!!!!!!!!