engine lacks power wtf

GhostBS said:

I have a 1976 cj5 renegade with a rebuilt 304v8. i replaced just about everything else under the hood when i bought it. it was running fine untill recently it started to lose power when i accelerate. it feels like i trying to pull something thats weighs way more than my jeep can pull. it also sounds like air is escaping...

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GhostBS said:

now it won't even start... the exhaust is custom, its basically headers and straight pipe... i am not getting any fuel to the carb, i just replaced the fuel pump and filter and its still not getting any... and no my gas tank is not empty...

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How can you hear anything going on with the engine with straight pipes blaring? My glasspacks were enough to mask 75% of engine issues!

Sounds like fuel *may* still be the issue. IOW, if you replaced the pump & filter and aren't getting fuel, there could be a pinhole on the fuel supply line somewhere between the pump and the pickup or pickup sock is filthy. Pull the supply line at the pump and use a hose into a gas can (safe distance from any sparks!)... should confirm/deny this theory.

Guessing the "air leak" you hear could be just the carbs venturi noise or a disconnected smog pump?

GhostBS said:

got her to start, she still bogs down... i don't really think there is an air leak now, some hoses were loose and i put them back on all the way. for the heat riser valve do i have to take off my headers?

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What did you do to get it to start? Spun it over until the FP primed? Starting fluid until it hit? It could take a while for fuel to make it to the engine once prime is lost!

IMO, skip looking for the heat riser valve, if you do have headers, I've never seen a set plumbed with the valve...

At this point, *if* you're getting fuel to the carb & it's stock (no Holley/4v crap), I'll wager it needs to be torn down & thoroughly CLEANED! This is based many years with a very cold natured MC2100 that would run great today and wouldn't get out of it's own way tomorrow. Luckily, the 2100 is one of the simplest carbs on the planet to mess with. I put mine on the shelf this year in favor of "DIY" TBI... and won't look back!

loss of power

hi just wanted to tell you i had a problem just like yours on my 81 jeep cj8 scrambler with sb chevy motor and eb 600 preformer carb..... really had several problems that casued motor to run bad and too rich...... would allways start but sometimes seemed ok for short time or if you shut off and restarted then would miss and run rough.........anyway it turned out to be vac leaks around the intake and base of the carb........... I would first make sure all intake bolts are tight...... you can use reg carb clearner,,,,,, just be carefull and have fire ex handly if you would start a motor fire......if your careful you should be ok...... the motor will speed up if you have a vac leak and when you spray the intake you will see big change in the motor speed........do same thing on and around the base of the carb......if that still does not make a difference...... take out both of the idle adj for both sides of the eb carb and blow them out with comspressed air....... these carbs are great but just a little crap in the fuel line will cause big problems ........when i got the vac leaks fixed and changed out the fuel filter then with the air bleu out the carb a couple of times all the problems went away and it is running great again......hope this helps...........one more thing...... eb ships all their carbs out on the rich side with the size of step rods springs and jets in their carbs.......... they are set up more for hot rods then a good smooth running motor......... if you rejet down a couple of sizes the carb with run better burn less fuel and you wont even feel any loss in power///// in fact you will have a quicker response and better runing motor except maybe on the very top end ....... and that would be way over 5,000 rpm which is not what we use our motors for or at in the jeeps anyway........

Interesting that you can cure a vacuum leak with a jack? That's one for the books!

How do you know the carb's not getting fuel? A vacuum leak doesn't stop the carb from getting fuel.

Will it start when you prime it?

Wild guesses!

A few simple tests should locate the problem - in a logical order.

Look at the color of the spark at one of the plugs - it should be a thin snappy blue one. Anything else indicates ignition problems.