1987 Rochester quadrajet

[Nick_1987 5.7 OMC]

Hello! I’ve owned this boat for a little over 2 years now, first time I’ve attacked a carb clean on this quadra jet. Completed it in about 2 hours. Carb looks very clean. I just have one question. In the video the guy had 4 brass pipe fittings for the vacuum. I had only the 2 outside for the secondary air bleeding valves. But not the other 2 throttle accelerater. I had the boat running last season like this and it was running ok. Are those 2 brass fittings ok to be missing or should I order some? I attached photo. Carb sits on a 1987 5.7 omc

 

[alldodge]

Without getting into your exact model, if the carb work good prior it will work good after

 

[Bondo]

Hello! I’ve owned this boat for a little over 2 years now, first time I’ve attacked a carb clean on this quadra jet. Completed it in about 2 hours. Carb looks very clean. I just have one question. In the video the guy had 4 brass pipe fittings for the vacuum. I had only the 2 outside for the secondary air bleeding valves. But not the other 2 throttle accelerater. I had the boat running last season like this and it was running ok. Are those 2 brass fittings ok to be missing or should I order some? I attached photo. Carb sits on a 1987 5.7 omc

Ayuh,..... My Guess is, the guy was workin' on an automotive version, not a Marine version,.....

 

[Lou C]

Yep that sounds about right. Is yours original to the boat?

 

[Nick_1987 5.7 OMC]

Yep that sounds about right. Is yours original to the boat?

Yes original to the boat and motor

 

[Nick_1987 5.7 OMC]

Without getting into your exact model, if the carb work good prior it will work good after

I did a carb clean because the engine would shut off at low rpm, around 550rpm. And coming off high rpm( 4500) to low rpm, the engine would stumble. The carb was pretty dirty so I’m sure the carb was the issue. Also have a new drive coming in soon aswell!

 

[alldodge]

I did a carb clean because the engine would shut off at low rpm, around 550rpm. And coming off high rpm( 4500) to low rpm, the engine would stumble. The carb was pretty dirty so I’m sure the carb was the issue. Also have a new drive coming in soon aswell!

Good deal

 

[Nick_1987 5.7 OMC]

Good deal

What else should I look for before season starts? I have a 5.7 omc. Anything to rebuild? Replace? Re assemble? I’m up to do anything that will cause me to lose time during the season!

 

[alldodge]

Change outdrive lube
Check Distributor cap and rotor, check plugs
Battery (cold not changing 12.5 to 12.7V, and is alternator charging right (14.5V)?

 

[Nick_1987 5.7 OMC]

Change outdrive lube
Check Distributor cap and rotor, check plugs
Battery (cold not changing 12.5 to 12.7V, and is alternator charging right (14.5V)?

Batteries are at 12.6 and alternator at 14.6. New drive will come with fresh lube. And what about fuel pump, or gaskets ? None of those?

 

[alldodge]

If fuel pump is not leaking then it should be good. Could check to see if your getting 3 to 7 psi with it working/running

No need for new gaskets if things are not leaking

Check gimbal bearing for smoothness

 

[Nick_1987 5.7 OMC]

If fuel pump is not leaking then it should be good. Could check to see if your getting 3 to 7 psi with it working/running

No need for new gaskets if things are not leaking

Check gimbal bearing for smoothness

Gimbal is getting redone, as well as bellows.

 

[Lou C]

If this is a Cobra, make sure that your ESA system works, it should lower the idle speed down to approx 450 from 600 when you trigger the interrupt switch. This is needed so you can easily shift from in-gear to neutral.
Normally it does not engage when shifting into gear, the ESA is needed to reduce pressure on the clutch dogs when shifting out of gear to neutral.

Also if you are new to OMC Cobras make SURE you fill the drive the correct way, or else it will be underfilled and you will burn up your upper gears. If these drives are maintained right and built right in the first place they are very durable. But there are some differences from Mercruiser that you must be aware of.

 

[Lou C]

I did a carb clean because the engine would shut off at low rpm, around 550rpm. And coming off high rpm( 4500) to low rpm, the engine would stumble. The carb was pretty dirty so I’m sure the carb was the issue. Also have a new drive coming in soon as well!

On the Quadrajet there are 2 idle air tubes inside the main body that can get clogged, they can be cleaned with carb cleaner and compressed air, and a very fine (.024") wire....take a look at the pix I put in this post...for great Quadrajet knowledge and support see:
www.cliffshighperformance.com
when clean and set up right they are an excellent, and very economical carb. With my little 4.3 4bbl I am amazed how little fuel it actually uses as long as you don't get into the secondaries.

 

[Nick_1987 5.7 OMC]

On the Quadrajet there are 2 idle air tubes inside the main body that can get clogged, they can be cleaned with carb cleaner and compressed air, and a very fine (.024") wire....take a look at the pix I put in this post...for great Quadrajet knowledge and support see:
www.cliffshighperformance.com
when clean and set up right they are an excellent, and very economical carb. With my little 4.3 4bbl I am amazed how little fuel it actually uses as long as you don't get into the secondaries.

On my carb I was missing the secondary accelerating well tubes, is that a problem?

 

[Nick_1987 5.7 OMC]

If this is a Cobra, make sure that your ESA system works, it should lower the idle speed down to approx 450 from 600 when you trigger the interrupt switch. This is needed so you can easily shift from in-gear to neutral.
Normally it does not engage when shifting into gear, the ESA is needed to reduce pressure on the clutch dogs when shifting out of gear to neutral.

Also if you are new to OMC Cobras make SURE you fill the drive the correct way, or else it will be underfilled and you will burn up your upper gears. If these drives are maintained right and built right in the first place they are very durable. But there are some differences from Mercruiser that you must be aware of.

Esa is working as it should. What are recommended batteries you would use for this motor? I use the boat to fish and run a few elecrtronics as well. What class batteries and how many would you install?

 

[Nick_1987 5.7 OMC]

On the Quadrajet there are 2 idle air tubes inside the main body that can get clogged, they can be cleaned with carb cleaner and compressed air, and a very fine (.024") wire....take a look at the pix I put in this post...for great Quadrajet knowledge and support see:
www.cliffshighperformance.com
when clean and set up right they are an excellent, and very economical carb. With my little 4.3 4bbl I am amazed how little fuel it actually uses as long as you don't get into the secondaries.

You there?

 

[Lou C]

I do think you need those tubes…I’d ask on Cliffs High Performance Quadrajets
As far as batteries I have two Deka group 27 dual purpose batteries & a Blue Seas 1,2,1+2,off switch.

 

[Nick_1987 5.7 OMC]

I do think you need those tubes…I’d ask on Cliffs High Performance Quadrajets
As far as batteries I have two Deka group 27 dual purpose batteries & a Blue Seas 1,2,1+2,off switch.

Ok sounds good, I’m gonna attempt to see if it starts, I had the boat running for the past season without those brass fittings. What should I expect when trying to start? Knowing the carb has to gas in it. Is there a certain procedure I have to follow to insure a quick and easy start up ?

 

[Grub54891]

Pump the throttle once, hit the starter.