Elelbrock idle issue

[boondockinak]

I have a 2004 EB 4-barrel on my 350 Chevy in my boat, electric choke, not sure of the cfm. Only has 200 hours on motor etc, and I'm pretty sure it's had this problem since day one, after I read some notes that the original owner wrote in the manual.


Anyways, had a rough idle once warmed up, and didn't want to drop below 1100 rpms. I dropped the idle screw down a scosh, and that helped drop the rpms down, but it would hardly stay running. Had a friend (old v8 guy) take a peak at it with me in the water, and he pointed out how the carb was dumping fuel in the primaries while at idle, like WOT kind of fuel at 850 rpms. We attempted to adjust the air/fuel idle screws, and there was no response or "cut out" as most guys call it, even when the air/fuel idle screws were bottomed out. Just tons of fuel dumping in.


Wouldn't the fuel be coming from somewhere else besides the Venturi's if there was a stuck float? And wouldn't typically only one side be flooding from a stuck float? Both of the primaries are dumping fuel at the same rate....




The rest of the time, the boat runs amazing, it's only an idle problem... I'm pretty stumped here....

 

[mad_yaker]

What's your fuel pressure? You check to see if your needle and seats clean? What's your float set at? Is the bowl clean?

 

[akshootnscoot]

How old is the carb? The Carb Shop in ANC does rebuilds for around $200. Any water ran through it? I had an EB in my old seine skiff (on a 360 Chrysler), and it seems like I needed to rebuild or replace on an annual basis. I had water issues with my fuel though. I may have the tuning DVD lying around if you don't have it figured out by this fall. I'm sure YouTube has several tuning videos as well

 

[Daved]

For sure, go get it rebuilt by the Carb Shop. They are very good at their craft. I have taken my Marine Edlebrocks to them several times. It will take you a week or so to get it back and it will be perfect. Maybe a couple turns to get the idle right. They get gummed up over time if water and other gunk goes through them. Sounds like a jet or valve is stuck. Extra fuel that can lead to a fuel leak, and in a closed compartment that equals a bomb at worst. Fuel problems on inboards are scary. Betcha when you get it all clean out, your boat will run even more amazing.

 

[Yukoner]

Have you pulled it off and really cleaned it yet? I pull my Edelbrock off each spring and use pretty much a whole can of carb cleaner on it.

 

[T.R. Bauer]

I have tuned and rebuild a LOT of Edelbrock carbs.....My one question to you, and this is a very important one, is how much vacuum does this thing have at idle? The reason I ask is because if this boat has a hotdog cam in it, or a vacuum leak, there have a tendency for the metering rods to lift out of their bores and flood the thing. With your description of visually seeing fuel out the primaries at idle it sounds like that is what is going on to me. You can easilly tune this out with different metering rod springs in like 5 minutes.

 

[boondockinak]

Cleaning is next on the list. I'm not sure what cam is in this motor, it's a stock 04' kodiak 310 horse 350. I'll look for vacuums leaks the next time I go out.

 

[Yukoner]

I have tuned and rebuild a LOT of Edelbrock carbs.....My one question to you, and this is a very important one, is how much vacuum does this thing have at idle? The reason I ask is because if this boat has a hotdog cam in it, or a vacuum leak, there have a tendency for the metering rods to lift out of their bores and flood the thing. With your description of visually seeing fuel out the primaries at idle it sounds like that is what is going on to me. You can easilly tune this out with different metering rod springs in like 5 minutes.

How many inches HG should you see on max vacuum? Great info.

 

[MacGyver]

Cleaning is next on the list. I'm not sure what cam is in this motor, it's a stock 04' kodiak 310 horse 350. I'll look for vacuums leaks the next time I go out.

Why wait it not like your going to see vacuum dripping down the side if the engine. It something you can look for at home.

 

[T.R. Bauer]

How many inches HG should you see on max vacuum? Great info.

A stock, or mildly built motor in good condition will have a steady needle and have 18-22. A motor with a large cam and is somewhat "built" will have 15 or less and some shake to the needle due to the valve overlap from the cam.

 

[T.R. Bauer]

Cleaning is next on the list. I'm not sure what cam is in this motor, it's a stock 04' kodiak 310 horse 350. I'll look for vacuums leaks the next time I go out.

A great way to look for vacuum leaks is to spray the area around the base of the carb, and where the intake seals to the head with small amounts of carb cleaner. If there is no change in RPM, you don't have any leaks. I don't think you are going to find a leak.....but who knows......A 310 horse 350 probably has some "cam" to it. I would check your how much vacuum you have before you start turning wrenches. If you don't have much vacuum, and the carb hasn't been tuned to your application, meaning it came out of the box and just slapped on, it can really run poorly.

 

[boondockinak]

A great way to look for vacuum leaks is to spray the area around the base of the carb, and where the intake seals to the head with small amounts of carb cleaner. If there is no change in RPM, you don't have any leaks. I don't think you are going to find a leak.....but who knows......A 310 horse 350 probably has some "cam" to it. I would check your how much vacuum you have before you start turning wrenches. If you don't have much vacuum, and the carb hasn't been tuned to your application, meaning it came out of the box and just slapped on, it can really run poorly.

Coming back to this after a very busy construction season. As its said, time and money are rarely found in the same place. Anyhow, I'm really handicapped here, how do I figure out how much vacume I have? Also, is it worth it to install a fuel pressure gauge and regulator before the carb?

 

[Doug from Anchorage]

Have you checked your float bowl assembly? A saturated float will cause dumping fuel I beleive.

 

[MacGyver]

Anyhow, I'm really handicapped here, how do I figure out how much vacume I have? Also, is it worth it to install a fuel pressure gauge and regulator before the carb?

What I would do is look at the engine shop manual or ask a marine engine technician.

I don't think you need to add a fuel pressure gauge or regulator. If you still want to, wait until you fix the problem.

 

[DRIFTER_016]

how do I figure out how much vacume I have?

Use a vacuum gauge.
http://www.amazon.com/INNOVA-3620-V..._2?s=automotive&ie=UTF8&qid=1415932777&sr=1-2