97 GTS bogging

[JoeV]

What's the biggest reason for bogging when trying to blast-off from idle to wide-open? Two suspects would be my idle is too rich (1-1/4 open when original was 1 open) or my pop-off is 38 instead of 30 (recommended). Wide-open is great and idle seems fine, but I didn't try to tune the idle. I can feather the throttle up in pulse stages to get it to wide-open.
Thanks for any comments.
JoeV

[Technical Support]

Bogging is rich, hesitating is lean. If you are rich and can be too low of a pop-off, not enough signal to the carb if you've modified things, being too rich on the mixture, carbs not properly synced and adjusted, etc.

[JoeV]

Thank you TS. Today I'll turn in the idle some and try that. It starts fine, and especially if I do a quick restart without throttle. Does it sound like the pop-off of 38 is therefore OK?
Thanks,
JoeV

[Technical Support]

Don't subjectively turn in your screws, especially such a large amount. When you are that close, a 1/16th turn may be all that's needed, and maybe only on one carb. Do low speed plug chops and get dialed in evenly first.

[JoeV]

Before I started leaning it in any, I discovered that holding the choke out about 1/2 a finger's thickness made it perfect on a hole-shot -- no bogging, or hesitating, just a quick clean take-off. So figuring maybe I needed to rich it out some I've gone all the way to 2-1/2 turns out with no improvement. It's actually loading up pretty bad on idle now in no-wake zones. But still the choke out a little makes for a good blast-off.

When I rebuilt the carb, I couldn't tell for sure if the high was 1/8 out or if it was 0. After rebuild I set it to 0.

That choke trick must be a clue to something, but I can't figure it. Does it tell you anything? Should I take the low back to 1-1/4 and back out the high to 1/8? The "delay" is as long as a second or more with no RPM change.
Thanks,
JoeV

[Bill O'Neal]

It tells me you need more vacume to pull the gasoline from your carbureators......

[JoeV]

Could the want for more vacuum indicate that my mylars in the pump are not seating real good and the pump pressue/volume is not real good?
JoeV

[Bill O'Neal]

Jetski "pumper" type carbs do not use pressure to operate them, although the fuel pump must build some small amout of fuel pressure to supply the fuel to the needles and seats. They use the air rushing past the inner venturi orfices, and orfices in the carb throat to "draw" the fuel from the carbs.

If you are needing to pull the choke to get enough fuel, your jets are either too small, or the orfices, filters or jets are clogged up in the carbs. It is possible that you need to rebuild the fuel pump too, to suppy enough fuel to the carbs.
Make sure the on-off-reserve switch is clear of debris, and that you still have the oring in the top of the water seperator/ filter bowl up under the hood.

[JoeV]

Thanks Bill. I guess I could have done better on my original post. I just rebuilt this single SBN on my 97 GTS and am trying to get it running right. This is first time in with the rebuilt carb. It worked perfect at the end of last season. I just opened it to check the internal filter, etc. The old filter had a small amount of small debris. I cleaned the whole thing inside and blew all passages out with compressed air - but everything inside looked clean to start with. The external bowl type filter was clean. When rebuilding I suspected that the new mylars were not relaxing to a tight seal. I used my original spring and the pop-off was 38, but sometimes it would take 42 to pop it. The needle/seat looked fine and would hold 20# for 24 hours. My original low was at 1 open, and the high might have been 1/8 open. I reinstalled to 1-1/4 open and 0 open.
It starts quick, idles great, and is great at WOT, when it gets there. Something seems to "get it together" or "catches on" after that 1-2 sec. delay. I don't believe it's anything electrical or external to the carb because the very small amount of choke fixes it. I just can't keep 1/2 a finger under the choke knob all the time.
Should I just pull it off and rebuild (re-gasket) it all over again?
Thanks, JoeV

[Bill O'Neal]

Yes you should. And put in a new needle and seat even though you think yours is good. I would really be looking at what you replaced as your problem if it worked before you rebuilt it.

Rebuild kits do not come with a new needle and seat. You must order it extra. It is usually ( but not always) the culprit in a bad working carb.

[JoeV]

Will do. Thank you a lot, Bill.
JoeV