Transitioning to Edelbrock 1409 from Rochester Quadrajet

[7362]

Ok, the (expensive) saga to repower my boat continues. I hope you guys can help me with the latest challenge. I've put in my new reman 350 block to replace my blown 305 cu in. It runs, but badly, related to fuel delivery. Stalls, power is poor, etc.

After numerous bad experiences with Quadrajet rebuilding and the reman units available from vendors ..I'm moving to Edelbrock. I've got the adapter plate and model 1409 carb. I have a few questions now that I am transplanting carb models.

First one, is this a good carb for use with Carter type electric fuel pump? My Rochester never did well with this type pump. Do I need an regulator to be installed in-line? Other recommendations to incorporate the electric pump?

The adapter plate has a vacuum vent hose fitting in the back. What's up with this, is it needed on a stock manifold-should I plug this hole in adapter plate?

Will my old Merc flame arrestor Part 85795, from Rochester, perform with this Edelbrock carb, , or do I need an (expensive) Edelbrock to be matched with the 1409 carb.

Had a divorced choke on the Rochester, now I've an electric one. I assume I can just apply 12 v across the terminals using the purple (+) wire (ignition switched fed, and same line which powers the fuel pump) and ground lead.

Last one, the top of the carb has an brass inlet fitting running into one of the inlet chambers, where does this connect to? It is located about 1" away from the fuel line inlet fitting.

Thanks very much for helping me make the switch over to Edelbrock.

THis thread may help others, as we're all in the same boat..

 

[dan t.]

Re: Transitioning to Edelbrock 1409 from Rochester Quadrajet

Bad mistake, find a real mechanic that knows carbs to overhaul your q-jet, you will be much happier in the long run.

 

[etracer68]

Re: Transitioning to Edelbrock 1409 from Rochester Quadrajet

All vacuum holes need to be plugged, or you will be running very lean.

 

[achris]

Re: Transitioning to Edelbrock 1409 from Rochester Quadrajet

The 1409 is a good carb. Plug the vacuum port in the adaptor base. The 1409 only wants 5-9psi from the pump. If the electric delivers that it will work fine. As for the flame arrestor, fit it and see, it should fit. You're correct on the electric choke, SWITCHED 12V and ground. The brass fitting near the fuel inlet is a dump port for the old mechanical pumps. It's the 'broken diaphragm pours fuel into the carb, not the sump' port. As you're using an electric pump, just plug that port....

HTH,

Chris...

 

[7362]

Re: Transitioning to Edelbrock 1409 from Rochester Quadrajet

The 1409 is a good carb. Plug the vacuum port in the adaptor base. The 1409 only wants 5-9psi from the pump. If the electric delivers that it will work fine. As for the flame arrestor, fit it and see, it should fit. You're correct on the electric choke, SWITCHED 12V and ground. The brass fitting near the fuel inlet is a dump port for the old mechanical pumps. It's the 'broken diaphragm pours fuel into the carb, not the sump' port. As you're using an electric pump, just plug that port....

HTH,

Chris...

Chris, Just a couple follow up questions. When you say plug the vacuum port on the carb adapter plate, do I put a cap on the existing fitting, or remove entirely, and get an threaded plug to install and seal? Same question for the fuel dump port on the top of carb, remove and thread a plug, or just cap it. --Just want to do this right.

Also-what is your take on the fuel pressure regulator? I have a JEGS one from this 1409 carb purchase, guess I will install and set to what PSI?

Also of interest is some folks say the 1409 electric choke is internally grounded, ie no ground lead needed. Do you agree? Thanks again for your help. Your post was appreciated!

 

[Bondo]

Re: Transitioning to Edelbrock 1409 from Rochester Quadrajet

Chris, Just a couple follow up questions. When you say plug the vacuum port on the carb adapter plate, do I put a cap on the existing fitting, or remove entirely, and get an threaded plug to install and seal? Same question for the fuel dump port on the top of carb, remove and thread a plug, or just cap it. --Just want to do this right.

Also-what is your take on the fuel pressure regulator? I have a JEGS one from this 1409 carb purchase, guess I will install and set to what PSI?

Also of interest is some folks say the 1409 electric choke is internally grounded, ie no ground lead needed. Do you agree? Thanks again for your help. Your post was appreciated!

Ayuh,... Plug 'em, or cap 'em, it don't matter, so long as they don't leak....

Yer fuel pressure should be set to 5 psi...

 

[achris]

Re: Transitioning to Edelbrock 1409 from Rochester Quadrajet

Chris, Just a couple follow up questions. When you say plug the vacuum port on the carb adapter plate, do I put a cap on the existing fitting, or remove entirely, and get an threaded plug to install and seal? Same question for the fuel dump port on the top of carb, remove and thread a plug, or just cap it. --Just want to do this right.

Also-what is your take on the fuel pressure regulator? I have a JEGS one from this 1409 carb purchase, guess I will install and set to what PSI?

Also of interest is some folks say the 1409 electric choke is internally grounded, ie no ground lead needed. Do you agree? Thanks again for your help. Your post was appreciated!

What Bond-o said... Set at 5 will be fine... If your electric pump is producing the right pressure, DON'T install a regulator... It will only drop the pressure too far down... And why add another item to fail?

'Internally grounded'... I'd still run a ground wire if there is a lug on the choke housing, or a ground wire to one of the screws on the carb if there isn't... I'm not paranoid! BUT!!!

Chris....

 

[7362]

Re: Transitioning to Edelbrock 1409 from Rochester Quadrajet

What Bond-o said... Set at 5 will be fine... If your electric pump is producing the right pressure, DON'T install a regulator... It will only drop the pressure too far down... And why add another item to fail?

'Internally grounded'... I'd still run a ground wire if there is a lug on the choke housing, or a ground wire to one of the screws on the carb if there isn't... I'm not paranoid! BUT!!!

Chris....

Chris, Well two last questions I think. Where is best place to measure fuel pressure? Right now I have a gauge on one of the two fuel separator mount bracket OUT ports, the other OUT goes up to the carb. Is this giving an accurate reading? I am not sure.

Also if I did use the regulator in the fuel system, I believe I would put the fuel out from the pump directly into the regulator and then the regulator output line going into the water separator, then from there up to the carb. Is this the correct flow path? Thanks much for any help you can give me. I owe you a beer. Cheers
MIke

 

[achris]

Re: Transitioning to Edelbrock 1409 from Rochester Quadrajet

Measure pressure at the carb inlet. Fuel flow should be... Fuel tank -> water sep filter -> pump -> regulator (if you really need to use it) -> carb. Use minimum 3/8" fuel lines, but larger is better....

Chris.....