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Lack of power

J

James L.

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"I have an 87 malibu sunsetter

"I have an 87 malibu sunsetter with 5.7L competition ski. I am experiencing a lack of power when accelerating. It feels like it bogs down, won't take all the throttle, and rpm won't come up fast. Eventually it will get going but doesn't have the power at holeshot. It has a new 1409 edelbrock carb, new inline fuel filter fuel/water seperator, electronic iginition, cap, rotor, wires. Any ideas would be greatly appreciated.

James"
 
If it has a smooth but hesitan

If it has a smooth but hesitant accelleration out of the hole when you punch the accellerator would suspect that the accelerator pump in the carbuerator is defective.
 
"Accel. pump may just need mor

"Accel. pump may just need more stroke. If it has more than one hole on the lever, change it to the hole that provides the longest pull."
 
"The accelleration is not hesi

"The accelleration is not hesitant, it just bogs down. Even with a new carb. would you suspect the accelerator pump being bad. The accelerator pump is on the hole with the longest stroke. Any more ideas. Thanks.

James"
 
Check the timing and see if it

Check the timing and see if it advances when rev'd. Sounds like it's starving for fuel. Check the pump squirt output--engine cold and off; give it a "hole shot" throttle in neutral and see what you get. Should see a pair of super squirts.

There is a filter in the mech. pump; how old is the pump and filter? Pump has sufficient output? If the flame arrester is screwed down too tight it can cause bore distotion. Make sure there is no binding in the choke and throttle plates. Clean flame arrestor.
 
I checked the timing in the dr

I checked the timing in the driveway and it advances- how far should it advance? I haven't checked the timing advance when under load- could it be different. The pump on the carbarator definetly squirts fuel when i advance the throttle in neutral.

I have never changed the fuel pump. All the other filters besides the one in the fuel pump are new. I checked the fuel pressure at idle in the driveway and got 6psi. Could the fuel pump still be bad or clogged.

I don't think the flame arrestor is too tight. It is clean. What is bore distotion? Electric choke is open- but how does it work exactly. Is is possible the choke partially closes when accelerating. Thanks

James
 
So the fuel pump has a filter

So the fuel pump has a filter internally. Is this easily changed or does the fuel pump need to be replaced? Thanks.
 
Electric pumps have a separate

Electric pumps have a separate canister filter. Older style mech. pumps have one made of a stone material and later models have a paper filter under the dome held in place by an inverted "V" clamp.

What is bore distortion? Carb. throat can become distorted from original shape if the flame arr. is tightened too much which makes the throttle and choke plates bind.

Electric choke is open- but how does it work exactly. Electric current heats a bi-metal coil with the ignition on and slowly opens the choke as the engine warms. Radiant engine heat will maintain it in the open position and it will close as the engine cools.

Is is possible the choke partially closes when accelerating. If the choke pulloff is not funtioning it might cause some mis-operation.
 
What is the choke pulloff? I

What is the choke pulloff? Is it common for the filter in the fuel pump to go bad. Is this easily changed or does the fuel pump need to be replaced? Thanks.

James
 
"What is the cfm rating of the

"What is the cfm rating of the 1409?
A 350 running at 5000 rpm only needs about 500 cfm of carb capacity, and if you greatly overcarb it, it will have trouble getting proper mixture at low rpm WOT situations.
Did this just start when the 1409 was put on?

Rod"
 
600 cfm. How can i prove this

600 cfm. How can i prove this is too much cfm.


James
 
"That's a perfectly well s

"That's a perfectly well suited carb for that size engine. See if you're getting about 26 degrees of advance at 3,000 rpms.

Jeff"
 
I've got the fuel pump apa

I've got the fuel pump apart. Where is the filter? How do I know if the fuel pump is bad or good. Thanks.

James L.
 
""Electric pumps have a se

""Electric pumps have a separate canister filter. Older style mech. pumps have one made of a stone material and later models have a paper filter "

"under the dome held in place by an inverted "V" clamp." If it doesn't have above, there isn't a filter in it."
 
Whats the best way to put the

Whats the best way to put the fuel pump back on. It seems to be hanging up on the rod. Thanks.

James L.
 
Have someone click the starter

Have someone click the starter a few times while you gently push on the rod until it moves off of the cam lobe.
 
"Got the fuel pump back on. T

"Got the fuel pump back on. Thanks for all your help. Going to test the boat this weekened, hopefully all is better. Thanks again.

James"
 
"So the boat acted no differen

"So the boat acted no different with the new fuel pump. Same exact problem going on, like it bogs down, won't take all the throttle, and rpm won't come up fast. It was also kind of hard to start last weekened, if that helps.

Any more ideas would be greatly appreciated. Thanks

James"
 
Do you have any vacuum lines a

Do you have any vacuum lines attached to the carb? What does the carburetor intallation intructions say about vacuum and the choke pulloff? I believe the pulloff diaphragm needs vacuum to open the choke when the engine is cold and you give it a goose. Call the manufacturer and tell them what is happening.
 
No vacuum lines. What is chok

No vacuum lines. What is choke pulloff?

Thanks.

James
 
"Top left of pic. Look at the

"Top left of pic. Look at the vacuum operated diaphragm with a vacuum nipple and a linkage rod connected to the choke. It requires a vacuum line to "PULLOFF the CHOKE" to allow sufficient air flow when more fuel is called for by the throttle.
114170.jpg
choke pulloff
 
"Yes it can. The one in the p

"Yes it can. The one in the picture is connected to a choke. If you have one, it needs a vacuum source to function; usually a plug can be found on the intake manifold."
 
The vacuum hole has a plug in

The vacuum hole has a plug in it from the factory.
 
Remove it and replace it with

Remove it and replace it with a brass nipple. It's in there pretty tight. I think someone said they used a square head nail set and a vice grip to remove it. I ground a 1" X 1/2" socket extension down to fit the opening.
 
Are you sure it's supposed

Are you sure it's supposed to have a vacuum line in it and not be plugged for some reason?

Thanks
 
"Guys; step in here!

If you


"Guys; step in here!

If your carb has an open vacuum port for the choke pulloff, where will you get the vacuum from? Does the carb have a vacuum operated choke pulloff? Yes? Then it needs vacuum. Call the manufacturer; I can't find a clear pic. of the 1409 on the web."
 
I apolgize. After closer insp

I apolgize. After closer inspection my carb doesn't have the choke pulloff. So I am not missing a vacuum line. Sorry for the confusion. Any more suggestions would be appreciated.
Thanks
 
"It sounds to me like it's

"It sounds to me like it's the distributor timing advance. When it bogs down, does the carb sputter? Backfire? Check your mechanical advance under your points/modual in the distributor. It might be sticking/rusted."
 
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