3.0 plug foul????

[mgatepi]

Hello All,

I have a 3.0 which has been recently rebuilt and converted to PMO 40's. The motor also has big port heads, 964 cams, MSD ignition, SSI's. IT has been running awesome, very strong and smooth, has about 600 miles on it since the rebuild.
Well until now.....last night I was on the highway for a period of about 5 miles, at normal speeds, went down the exit ramp and stopped to make the turn. When I began my turn and started to accelerate it begin to cough and hesitate and would not pull until the motor reached about 3000 RPM's....and since then has been running / idling very rough until I reach about 3000+ RPMS. Any ideals? Fouled plugs? What type of plug should I use? Currently using an NGK. Anything else??

Thanks!!!!!
mg

[schumicat]

the only way to tell if you have fouled plugs is to pull them. you can also have a shop with a gas tester see whether it is running rich (which could cause fouling).

[BURN-BROS]

Two possibilities;

It is often necessary to retune a fresh motor after it has broken in.

Trash in the fuel system has compromised one or more of the idle circuits.

[mgatepi]

Thanks for the suggestions! I plan to pull the plugs and check today. I guess I am looking for someone to say that this is possible to happen, from running awesome to crap in a matter of seconds???

If I have dirt in my idle circuits, what is the best way to clean it out? I am filtering the fuel through the CIS filter (with a new element) I did not use the small canistor filters that came with the PMO's. Is the CIS filter not adequate?

Thanks for all the help!!!!
mg

[BURN-BROS]

The CIS filter in more than adequate. You can adjust the mixture screws of each cylinder. Follow the instructions for adjusting to best lean on any of the Weber sales/service sites.

If you are uncomfortable with mixture adjustment have a pro do it as you can quickly misadjust as set of carbs to where the car is not drivable.

[Joe Bob]

Clogged idle circuits, jets, can be cleaned with compressed air and/or properly sized reamers.

If the jets ARE clogged, something got past your filter. Since you are using low pressure, clear filters inline prior to each carb would be a good idea.

Back in the day, the ones I used could be backflushed.

[Les Paul]

A broken guitar string works well cleaning idle jets. I had hell with my 356 plugging jets till I went to a different filter.

[mgatepi]

THANKS FOR THE SUGGESTIONS!
I swapped out the plugs with new and no improvent. So no fouled plugs. I will take the idle jets out and blow them out next.
Thanks
mg

[Les Paul]

The crap I used to get was like silica. Sometimes lodged in so hard you have to ram it out. Wire brush wire works well too.

[mgatepi]

I removed the jets and blew them out......all is good now!!!! Runs great!!!

Thanks for all the help!!!
mg

[Joe Bob]

Changing and adding additional filters? Otherwise, the problem may repeat itself.

[mgatepi]

Also added in line filters!!!!!
mg