Stinky, sputtering bronco, carb too big?

[skrit]

Asked my local mechanic the following questions:

Why does it take several minutes to warm the engine up without it cutting off when I let off the gas pedal?

Why does it sputter when I cut the engine off?

Why does the exhaust stink like gas vapors?

He said the the Holley 1850-3 4160 600cfm carb is too big for the 351W which makes it run too rich. Does this make any sense?

 

[Apogee]

Asked my local mechanic the following questions:

Why does it take several minutes to warm the engine up without it cutting off when I let off the gas pedal?

Why does it sputter when I cut the engine off?

Why does the exhaust stink like gas vapors?

He said the the Holley 1850-3 4160 600cfm carb is too big for the 351W which makes it run too rich. Does this make any sense?

Sounds like it just needs to be tuned. I've got a 670 Holley T/A and while it does run a little rich initially, it runs great.;D

 

[DRBRONCO69]

The 1850 series carbs are perfect for 351w. It is a good carb but out of the box needs tuning and tweaking. They work really good once tuned. Make sure that the choke is working properly also. Choke may need to be adjusted if electric. If it is a manual(cable) choke then your probably ok on the choke and I would start looking for vacuum leaks somewhere.

 

[broncnaz]

600 cfm is fine for a 351W your starting problem is due to a choke adjustment sounds like it needs more choke or it could have to much. As for sputting when turning off thats usually a timing problem could have to much advance which can also cause the stinky smell. Check your plugs after getting everything adjusted. Black = rich white= lean grey to brown is where they need to be. you may need to rejet the carb if you get black or white plugs.
I would get a rebuild kit for your carb mainly to replace the power valve as when they go bad they can cause it to run rich. ie sputter and smell.

 

[Apogee]

Broncnaz has a good point about the timing...if it's off and it diesels when you shut it off, I wouldn't be surprised at all if the power valve has been blown out of it during a backfire or something.

Depending on the overall condition of the engine, compression, cam, etc...all of that is going to effect your timing and carburation as well. There's not a lot of carb tweaking and timing setting you can do that will add compression or vacuum or put lobes back on your camshaft. ;D

 

[skrit]

Ok, this is what I have so far. Now which to do first?

1. check/adjust timing
2. tune carb
3. re-build/install power valve in carb
4. adjust electric choke

Should I just take it to another mechanic and tell them to do a complete engine/carb tune up? I'd like to have the engine thoroughly inspected to see if it operating correctly because I don't know how to check/adjust any of that stuff.

 

[DRBRONCO69]

Ok, this is what I have so far. Now which to do first?

1. check/adjust timing
2. tune carb
3. re-build/install power valve in carb
4. adjust electric choke

Should I just take it to another mechanic and tell them to do a complete engine/carb tune up? I'd like to have the engine thoroughly inspected to see if it operating correctly because I don't know how to check/adjust any of that stuff.

I am not sure how mechanically inclined you are but I would start with the basic suff( the stuff that doesn't cost anything) and go up from there.

1. check timing
2. tune carb(idle mixture)and base idle and adjust choke
3.Replace the power valve( they blow out all the time. It only takes one backfire to kill it.)
4. If you still have problems I would start to look elsewhere. Tune up, what distributor and coil are you running, wire condition, vacuum leaks, etc. The holley 600 is a very basic carb and if you purchased it new, it should have directions on how to set it up. The mixture screws get turned in to lean the mixture out and out to richen it up.

Holley Performance Products provides technical support via phone Monday through Friday, 8AM to 5PM CST @ 270 781-9741.

Mike

 

[Skiddy]

At this point, do you have gas in your oil. Could explain your engine knock.

 

[DRBRONCO69]

At this point, do you have gas in your oil. Could explain your engine knock.

Skiddy, I think you replied on the wrong thread?:? No knocking on this one.

 

[Skiddy]

Skiddy, I think you replied on the wrong thread?:? No knocking on this one.

ok well maybe but he may not need to go any further;D check his other thread

 

[DRBRONCO69]

ok well maybe but he may not need to go any further;D check his other thread

LOL ;D ;D that may explain the running and stalling out problems all in one!!!!!!!!!%) %)

PULL THE MOTOR!

 

[kyle]

I would solve the carb issue first. The sputter after shutoff could be linked to the idle setting on the carb, or just a worn out carb. It may not be timing at all.

 

[skrit]

The carb came on the engine when I bought the bronco. I took it off, cleaned it and added an electric choke. How do you adjust the electric choke?

I have another post on an engine knock. Between the carb issue and the mysterious knock, I'm starting to get real worried

 

[broncnaz]

Here's a link to some basic instructions. http://www.holley.com/data/Products/Technical/199R7948-5.pdf
I thought there was some better ones with a measurement for the choke plate but I'll have to check when I get home it may onlt come in rebuild kits.