1997 Challenger 800cc fuel starvation

[rockytsi]

My 97 challenger appears to be fuel-starved. It idles ok, but when I run the throttle up it bogs intermittently as though it cant get enough fuel.

1. I have pulled the carbs and cleaned their components, blown them out with comp air.

2. The sparkplugs are dry, as though not enough fuel. (new plugs) How important is the plug gap? I bought the req'd plugs, but dont know what they are pre-gapped at.

3. The fuel filter is clean, as were the internal carb filters. I tried switching to reserve, with the same result, bogging/surging.

4. The fuel lines are black.

I have been told to run it and hold a blow torch (unlit) in the engine compartment to see if its getting air....any thoughts?

Also, is there a filter in the tank that could be dirty?

I am expecting company this weekend and would like to get this issue solved....please help.

Thx,

Rock

 

[dsw222]

a blowtorch in the engine compartment? what would that do?

the plug gaps are important... and they are not gapped correctly from the spark plug company. i believe they are gapped to like .036 and theyre supposed to be .022... so thats almost double what they should be

what are your high speed screws and low speed screws set to? and at what RPM are you idling?

 

[pincusa]

I can't figure out what you'd do with a blow torch in the engine compartment other than cause more problems for yourself.... But after the engine runs, the plugs shouldn't be wet with fuel, so not sure that's a good indication of starving it.

If the engine will idle but not throttle up, I'm guessing your your carbs are still clogged up. Take them apart and clean them out with carb cleaner. Be sure to remove the needles and then blow it all out with compressed air.

If you can throttle up but not get past say 5000 RPMs, you want to also look at the rave valves and clean them out.

If you really think it's fuel starvation, look at your fuel pumps and make sure the pulse line is well seated. You can also take it apart and clean it out. But be careful of the gasket as I couldn't find a replacement source for them.

 

[dsw222]

If you really think it's fuel starvation, look at your fuel pumps and make sure the pulse line is well seated. You can also take it apart and clean it out. But be careful of the gasket as I couldn't find a replacement source for them.

if you mean the circular gasket that has a metal bar on it in the accelerator pumps... ParkerYamaha has them

 

[parrothd]

My 97 challenger appears to be fuel-starved. It idles ok, but when I run the throttle up it bogs intermittently as though it cant get enough fuel.

1. I have pulled the carbs and cleaned their components, blown them out with comp air.

2. The sparkplugs are dry, as though not enough fuel. (new plugs) How important is the plug gap? I bought the req'd plugs, but dont know what they are pre-gapped at.

3. The fuel filter is clean, as were the internal carb filters. I tried switching to reserve, with the same result, bogging/surging.

4. The fuel lines are black.

I have been told to run it and hold a blow torch (unlit) in the engine compartment to see if its getting air....any thoughts?

Also, is there a filter in the tank that could be dirty?

I am expecting company this weekend and would like to get this issue solved....please help.

Thx,

Rock

blow torch could be used to locate an air leak, but it's like using a match to find a leaking gas pipe.. LOL...

I'd use carb cleaner or brake cleaner, you can spray it on suspected leaking areas and see if it changes the engine idle, but usually the overspray gets sucked into the intake messing up the results...

 

[parrothd]

Did you check the accelerator pump is working? (not sure if you're boat has them) search the forum..

 

[rockytsi]

The idea of the torch is to put it near each fuel line fitting. If air was getting in there, the propane would be sucked in and used as a fuel source, thus detecting the leak.

Not even sure where the accel pump is, if it has one. I will search and find out.

I have replaced raves with two new ones, $135 each.

The reason I think its fuel starvation is that when i took it out saturday and throttled up it began surging. I then tried throttling up and manipulating the choke a little (1/4 choke) and it ran almost fine, smooth and fast at 7000rpm.

I will verify the idle rpm tomorrow.

I will have to remove the carbs again and re-clean them. I will also drain the fuel and replace with fresh fuel. Is there a filter in the fuel tank?

 

[parrothd]

You're boat does have an accelerator pump.

When you have the flame arestor off, look down into the carbs throttle body, there should be a small nipple in each carb, have some move the throttle to wide open quickly, you should see a small squirt of fuel in each carb, if not the accelerator pump is either clogged or broken diaphragm...