6 Pack Plug Fouling Problem

[R413]

None should really run higher than the sight plugs. Will not help anything, only mask a delivery problem, and potentially cause other problems.

Get a pump that can keep up with the fuel needs of the engine without. Having the float level too high.

I bough a car with a 6 pack, near stock, with a holly electric chainsaw pump out back, he said it would starve for fuel without it. Well he caused many problems with adding a regulator, press gauge, etc. kinked lines, restricted fittings. I removed all his garbage and then a stock pump kept it fed just fine.

 

[Chargered]

The end carbs do not have replaceable jets...they have metering plates UNLESS you've changed to the PROMAX conversion units. Also look for a leaking power valve gasket or bad power valve diaphragm in the center carb. I run my carb float levels "slightly" below the sight port threads.....helps with percolation.
BOB RENTON

I have mechanically actuated outboards with replaceable jets. I'll replace the PV and hopefully get the carbs back on this weekend with a new set of plugs and see if I'm still fouling.

 

[Chargered]

None should really run higher than the sight plugs. Will not help anything, only mask a delivery problem, and potentially cause other problems.

Get a pump that can keep up with the fuel needs of the engine without. Having the float level too high.

I bough a car with a 6 pack, near stock, with a holly electric chainsaw pump out back, he said it would starve for fuel without it. Well he caused many problems with adding a regulator, press gauge, etc. kinked lines, restricted fittings. I removed all his garbage and then a stock pump kept it fed just fine.

Another thing that has me curious is that I really have to adjust my float nut almost all the way down to keep the fuel level at the bottom of the sight plug. I have to crank them down almost to the point of running out of threads.

 

[R413]

Just your combination of needle and seat assemblies, and the floats.

 

[RemCharger]

Another thing that has me curious is that I really have to adjust my float nut almost all the way down to keep the fuel level at the bottom of the sight plug. I have to crank them down almost to the point of running out of threads.

Is this mainly on the outboard carbs??

 

[Chargered]

Is this mai

Is this mainly on the outboard carbs??

It is worse on the outboard carbs. I nearly run out of threads on the outboards, the center isn't as bad, but close.

 

[RJRENTON]

I have mechanically actuated outboards with replaceable jets. I'll replace the PV and hopefully get the carbs back on this weekend with a new set of plugs and see if I'm still fouling.

Appologies......Incorrect assumption on my part, I thought that you had an origional six barrel set-up with vacuum operated end carbs. Since you are using mechanical operated end carbs, it MAY be possible that fuel is being pulled over thru the carbs accelerating pump delivery system (if present)....missing fuel discharge check valve? Just thinking out loud.......
BOB RENTON

 

[Chargered]

Appologies......Incorrect assumption on my part, I thought that you had an origional six barrel set-up with vacuum operated end carbs. Since you are using mechanical operated end carbs, it MAY be possible that fuel is being pulled over thru the carbs accelerating pump delivery system (if present)....missing fuel discharge check valve? Just thinking out loud.......
BOB RENTON

Good point. As long as I have the carbs off, I'll take a look at the accelerator pumps.

 

[BeeFast]

Whats your fuel pressure reading? Did you check it early on?

 

[Chargered]

Whats your fuel pressure reading? Did you check it early on?

If I remember correctly, it was reading around 6 psi when my gauge was still working. Now my gauge seems to be bad because the needle is bouncing around so much its hard to tell.

 

[66Satellite47]

Not sure which mech end carbs you have. IIRC there were several versions available. The float bowls and floats are very different than the OEM vacuum end carbs. The only time I had the deep needle/seat & nut issue was with a non Holley needle & seat with the very thick brass adjuster nut. The Holley needle & seat with the thin Holley nut has always worked fine for me.

 

[RemCharger]

I thought the end carbs were supposed to run 1/2 way up the sight plugs... or was that just the 340s??

I just had to dig in a manual... take a look at the sight plugs. They are indeed lower than the center as I thought.
When I set up a T/A 340, I remember reading to use clear sight plugs on the outboards, and put them half way up. This was some kind of performance bulletin, but that was a long time ago.
Anyway, that car has always run well with that tune up.
All of this makes sense, when the complaint is having to crank the needle&seats too far...

 

[BSB67]

I just had to dig in a manual... take a look at the sight plugs. They are indeed lower than the center as I thought.
When I set up a T/A 340, I remember reading to use clear sight plugs on the outboards, and put them half way up. This was some kind of performance bulletin, but that was a long time ago.
Anyway, that car has always run well with that tune up.
All of this makes sense, when the complaint is having to crank the needle&seats too far...View attachment 1349668

Yes it was in the Bulletins and common with racers. The reason was to initiate the fuel delivery sooner with less signal. The goal was to open outboard cars at the fastest rate while minimizing the lean hole created when they started to open.

 

[66Satellite47]

Keep in mind the OP does not have OEM end carbs. The manual and likely the bulletins probably don't apply to the aftermarket mechanical end carbs.

 

[BSB67]

Keep in mind the OP does not have OEM end carbs. The manual and likely the bulletins probably don't apply to the aftermarket mechanical end carbs.

Correct.

 

[Chargered]

I went to put in a new power valve tonight, I grabbed a hold of the old one in the metering block and it twisted right off by hand. It wasn't tight at all. I looked at the book and they are supposed to be tightened to 120 in./lbs. Could this have been the cause of my plug fouling? Maybe if it wasn't tight, fuel was being pulled through the gasket area.

 

[68 HEMI GTS]

I went to put in a new power valve tonight, I grabbed a hold of the old one in the metering block and it twisted right off by hand. It wasn't tight at all. I looked at the book and they are supposed to be tightened to 120 in./lbs. Could this have been the cause of my plug fouling? Maybe if it wasn't tight, fuel was being pulled through the gasket area.

If the P/V was loose it was leaking fuel right by and into the engine. Most definatly an issue. The mechanical outboards (if you have 4783’s) don’t have a whole lot to them. No P/V’s, non adjustable idle circuit, only thing really to go wrong would be needle and seat issues/float level. They are somewhat primitive.

 

[Chargered]

If the P/V was loose it was leaking fuel right by and into the engine. Most definatly an issue. The mechanical outboards (if you have 4783’s) don’t have a whole lot to them. No P/V’s, non adjustable idle circuit, only thing really to go wrong would be needle and seat issues/float level. They are somewhat primitive.

You described my outboards exactly right.

 

[68 HEMI GTS]

You described my outboards exactly right.

I know them well, I have a set I run on a stroker. I had to add adjustable idle circuits to make them work right on my application.

 

[66Satellite47]

A loose P/V would cause much of your problem. Hope you can make those end carbs work for you.