93 SkiRay MerCruiser Tournament 350 - carb adjustment

[steve_93_skiray]

Hi,

I've been having idle issues (also gas smell) with our boat recently and I've tried adjusting the idle screw and the 2 screws on the 4 barrel carb.

The left carb screw doesn't seem to do anything, while the right screw does.

It seems to idle around 750 rpm, but sometimes 10,000 rpm, not sure why it would change.

It also sounds like it's sputtering, never used to do this.

 

[steve_93_skiray]

Anyone know why the left screw doesn't do anything?

Does it sound like it needs a rebuild?


thanks!

 

[scoflaw]

Yes, rebuild it

 

[Scott215]

Yes the carb need to be rebuilt. Each screw should have some effect on the vacuum and idle

 

[atrick]

One screw for left, one for right barrell, turn each screw in till they bottom then back out 1 1/4 to 1 1/2 turn for a starting point then fine tune each the same till you get a smooth idle

 

[Scott215]

You can use a vacuum gauge to get the highest reading and each one. Use idle screw to keep it running than set final idle

 

[steve_93_skiray]

One screw for left, one for right barrell, turn each screw in till they bottom then back out 1 1/4 to 1 1/2 turn for a starting point then fine tune each the same till you get a smooth idle

yeah, the right one works, but the left does nothing (seen in the video).

ill find a rebuild kit for it and try that over the winter.

is there a trick to finding the correct rebuilt kit?

 

[Scott215]

Call a MerCruiser deal and give them engine serial number or the number on the carb

 

[atrick]

Sierra makes the kits as its probably a quadrajet by rochester the three parts that wear out are the float needle and seat and the accelerator pump, you'll also have to reseal with JB weld inside the float chamber where the factory sealed some bore holes, they start leaking with age and when the boat sits for awhile the fuel leaks out into intake manifold.

 

[Scott215]

Could you please explain the jb weld part. Been building street race cars for 30 years and never heard of that

 

[atrick]

You can find it on youtube its a Q-jet problem on the older ones, had to do it on my merc, what ever they use to seal it with starts failing over the years and the fuel in the fuel bowel slowly leaks out so when the boat sits for a period of time the float bowel needs to fill back up before it will starts which makes for hard starting.

 

[Scott215]

Okay thank you I've never heard of that

 

[Johnc3211]

It's not a quadrajet. It's a Weber (aka, Edelbrock, or carter AFB if you are old enoughto rember). Easy to rebuild. Lots of Youtube videos to help.

 

[Scott215]

Yeah sure have even the thermal quad on Chrysler's

 

[Espos4]

It's not a quadrajet. It's a Weber (aka, Edelbrock, or carter AFB if you are old enoughto rember). Easy to rebuild. Lots of Youtube videos to help.

Carter AFB (aluminum 4 barrel) or AVS (air valve secondary)?

I’ve got an AVS on a ‘69 Dodge that looks like the current Edelbrocks.

 

[Scott215]

Why not just buy a new Edelbrock avs

 

[steve_93_skiray]

Here’s some photos of it with the flame arrestor off.

There’s a number on the flap thing 7W8506 and it seems to be an Edelbrock? I couldn’t see any other numbers on the carb.

I removed the left screw and cleaned it, sprayed some seafoam in the hole etc, still does nothing. Someone told me it’s for the other 2 barrels which are used when it’s more WOT rather than idle. Is that true?

 

[Scott215]

Get a rebuild kit from Edelbrock

 

[scoflaw]

Those 2 screws are for idle adjustment, both sides. The rear secondary's don't come into play when idling and there is no adjustment for them, just a jet change if needed.

 

[Johnc3211]

If you want to rebuild it yourself, try www.carburetor-parts.com. Mikes carburetor is great. Everything you need and videos to help. My 93 250 EC 5.7 was getting terrible fuel mileage, and putting smelly black residue out exhaust at startup. Couls see gas dripping down inside carb after shutoff. Used Mike's kit and instructions, works great now. Highly reccommend.