89 5.7 Cobra running issies

[Lou C]

Well then that’s the well known bog that happens on a Quadrajet where the secondary air door opens up to soon and the on-rush of air is too much for the carb to adjust for. So you need to learn how to adjust that properly. Do a bit of research, its a well known Q-Jet issue, but not difficult to correct.

 

[Cjpainten]

Ok thanks I'll give it a try .

Is that something that was a factory defect?

 

[Lou C]

not really its an adjustment that is the responsibility of the installer. Like setting the idle mixture and idle speed. Carbs are not plug and play they need adjustments to work right. This knowledge has been lost on the plug and play generation who has only driven EFI vehicles. We had to play with our carbs to get our cars to run right back in the day (ie 60s-right up to early-mid 80s) and old school boats are the same. So do some reading, you might be able to get what you have there working just fine....

 

[Cjpainten]

If I could get a cloudy day I might be able to work on this instead of hanging out on the lake with my other boat

Previous owner had it installed and setup at the marina but you never know...

 

[PITBoat]

If I could get a cloudy day I might be able to work on this instead of hanging out on the lake with my other boat

Darn it! I hate when that happens...

Previous owner had it installed and setup at the marina but you never know...

If the marina knew what they were doing, we wouldn't need this and other sites, unfortunately. It's not just about wanting to save a few bucks, it's about it being hard to find conscientious mechanics that REALLY know what they are doing.

To the best of my memory, there's one little set screw... you set it right and you get WAAAHHH when you're into the back 2 bbls; you don't, and you don't get them at all, or you get a big bog down.

 

[Cjpainten]

Threw the new carb on... Small improvement but it's still missing above 2500

What's next? Fuel pump??

 

[Scott Danforth]

cleaning your fuel system is the proper next step

 

[Cjpainten]

I will also check the pickup for debris. I may also try running it off a gas can and see if that helps

 

[Cjpainten]

Quick update... Threw a new coil on and took her out on the lake.

First 10 minutes she ran decently (wouldn't go above 4000 rpm / 40mph

Anchored about an hour then started heading back to the launch. At first she wouldn't go over 2k wothwit stalling, then 1500, then 1k, and finally I basically had to idle back

I am going to check the tank pickup right now as it seems it's definitely a fuel delivery issue

another think I noted, it was hard to take the boat out of gear. Maybe the shift interrupt module is malfunctioning???

 

[Cjpainten]

Changed the pump, checked lines... Still missing

Just checked the shift interrupt (pressed in switch) and it changes nothing.

Switch works so it's gotta be the module correct??

 

[Cjpainten]

Disconnecting module did nothing to change rpm.

 

[Cjpainten]

Dumping isopropyl alcohol in the fuel tank and taking her out. Fingers crossed.

There still was water droplets inside the carb

 

[Cjpainten]

Still no luck, it's actually running worse than ever

Running very rich, missfiring

I ordered a voyage est distributor hopefully that fixes the problem

 

[Bondo]

Running very rich,

Ayuh,..... Sounds like a Carb problem,......

 

[Cjpainten]

I already replaced the carb and same issues remain

Also it gets worse as the motor warms up

 

[bruceb58]

What would ignite it if it's timed correctly? I use it on my old pickup if it sits for more than a week, to save the starter.

It's called piston destroyer for a reason. It can ignite early just from the compression itself.

 

[bruceb58]

I ordered a voyage est distributor hopefully that fixes the problem

Your ESA won't work properly as is with that distributor. CDI has an ESA that will work with it. You will have to do some wiring changes to add it to your distributor.

 

[Cjpainten]

I rewired it to run like a Mercruiser already because the ESM wall malfunctioning and I couldn't get it out of gear

 

[bruceb58]

I rewired it to run like a Mercruiser already because the ESM wall malfunctioning and I couldn't get it out of gear

That will work fine as long as the lower shift cable stays in good shape. Make sure you keep the overstroke switch in the circuit.

 

[Cjpainten]

The overstroke switch seems to already be tied into the interrupt switch. There were only 2 wires inside the connector