'90 5.7 Takeoff

[sstone]

Thanks to help and a lot of info found here, I brought my 1990 5.7 cobra back to life after a 10 year nap. It runs great, and being a lot of motor on a 20' boat it goes pretty fast, and takes off quick. If I jump on it too hard though it hesitates for a little and occasionally backfires through the carb. Might be a dumb question but Is it getting too much or to little gas in the pump shot? Or another problem? 4 barrel Holley, I think 4011, vacuum secondary. Thanks.

 

[bruceb58]

Re: '90 5.7 Takeoff

That's a lean condition. With the engine off, look down the carb throat and see if the accel pump is squirting fuel when you advance the throttle.

Also, mashing the throttle can cause this. Don't mash the throttle.

 

[sstone]

Re: '90 5.7 Takeoff

It squirts a lot of gas down it, no problem there. Just rebuilt too. But I may have been mashing it. Has a real short throttle distance and I've never driven it before

 

[Howard Sterndrive]

Re: '90 5.7 Takeoff

It squirts a lot of gas down it,

but not enough if it's backfiring

 

[cr2k]

Re: '90 5.7 Takeoff

Power Valve. probably dried out over it's sleep. Easy to blow on a Holley. One back fire and gone. Use a high altitude or marine one.

 

[sstone]

Re: '90 5.7 Takeoff

Power Valve. probably dried out over it's sleep. Easy to blow on a Holley. One back fire and gone. Use a high altitude or marine one.

Just rebuilt it, replaced all the good stuff, with a marine rebuild kit. It didn't misbehave any afterwards, but I'll check it. I'm thinking I just mashed it too hard