Hello all, I have two 98 GTX limited that I have rebuilt and I’m having troubles with dying going from idle to WOT. The accelerator pump works on the one but it seems like anywhere I adjust it it still has a little bog. As for the other one, the threads for the adjustment screws are stripped so I am wanting to just delete both of them and go with bigger jets. Does anyone know what size jets would work with the accelerator pumps deleted? And would I have to adjust pop off pressure at all?
98 GTX Limited - Accelerator Pump Delete
- Thread starter CliftonWC
- Start date
Negative on that one. Adjustment screw moves the accelerator pump lever in or out on the throttle to adjust when the fuel is being squirted at a certain throttle position.
Yes, I know what it does, I am saying it doesn't need adjustment from the factory setting. If you are bogging then you have something up with the carbs, not the accelerator pump adjustment.
Are you running the stock airbox?
951's are very lean from the factory and by design so they really need the accelerator pumps. They don't respond as well to eliminating the accelerator pumps as the 787/720 engines do due to the lean design of the carbs and inlet signal of the engine.
Are you running the stock airbox?
951's are very lean from the factory and by design so they really need the accelerator pumps. They don't respond as well to eliminating the accelerator pumps as the 787/720 engines do due to the lean design of the carbs and inlet signal of the engine.
Yes stock airbox, although I think it has some inlet ports that mount to the angled brackets on the top of the motor that are missing. I adjusted low and high speed to factory settings. When I get into the high jet it takes off, idle I have it turned a hair rich (about 1.5 turns). It idles fine but the second I go to throttle up it starts dying. I have to blip the throttle to get the RPMs to get up to around 4k to hit the high jet. Once it does hit the high jet it goes and I ran it full throttle and cut the motor to check the plugs and it was a little wet but a perfect coffee color.
Venturian1
Member
I 2nd that motion for the transition holes being partially blocked. When I cleaned the three holes in my carb bore, it made a big difference, no more bogging at all! I don't know about yours, but my 98 GS with the accelerator pump has a recharge jet, in, the gas hose that supplies fuel to the acc pump diaphragm. Its in the parts catalog.
Sounds good. I’m gonna pull the carbs out this week and take a look. I have recharge jets on order.
Venturian1
Member
Be sure to blow out the three small holes in the bore of the carbs close to the throttle plate.
one of them is connected with the low speed air/fuel mixture screw. remove the screw and hold a finger or plug the threaded hole
with a rubber plug when blowing it out. I use brake parts cleaner. It comes in a spray can and includes a tiny red tube that fits into the spray nozzle
for concentrating the spray. Another hole is connected to the small jet, which should be removed first. I forget what the 3rd hose is connected to, and there'salso a 4th hole that runs straight to the main jet. This hole is in the venturi part of the carb bore. I have only one carb on my 98 GTS so it may be a little different than your two carb set up. Another thing to check is the return line orifice that's built into the carbs. There's not much you can do other than make sure they aren't plugged or partially blocked. I assume they are there to maintain some fuel pressure in the carb(s). This should be in your PTO carb. Synchronizing the throttle plates is critical also. I back out the idle adjust screw until its not touching the throttle linkage. then hold the carbs up to a light and look through the bores. The amount of light if any you see around the mag side carb's throttle plate should be the same as the PTO carb. And, of course, vacuum test all fuel hoses, filter, and fuel select valve. sometimes they can hold pressure but then leak with vacuum. I pull the fuel hoses off of the tubes on the tank when doing this, and put a golf TEE in the end of each hose. and check the plastic nipple on top of the tank for cracks, or deformed from overtightening a fuel hose clamp.
