IH PARTS AMERICA
Click Here!

Go Back   IH PARTS AMERICA > Tech Forums > Carb Tech
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read Photo Gallery IH Store Home

Reply
 
Thread Tools Display Modes
Old 10-31-2018, 06:04 AM   #1
robeastunder
Junior Member
 
Join Date: Feb 2016
Member Number: 8101
Posts: 18
Default Edelbrock Thunder 1806 on stock 392

I bought a 74 2wd Travelall with a stock 392, it came equipped with a Edelbrock Thunder 1806, has anyone every run this carb on a 392? its running pretty rich and stumbles when you floor it or even at 1/4 throttle it will stumble when stomped, PO claims it was been sitting for quite some time, did a redneck tuneup, plugs, wire, cap and rotor, plugs were showing a very rich running carb, anyway suggestions are appreciated on the next step.

Thanks,

-Rob
robeastunder is offline   Reply With Quote
Old 10-31-2018, 07:44 AM   #2
1975IH200
Senior Member
 
1975IH200's Avatar
 
Join Date: Dec 2008
Member Number: 731
Location: 3rd to last cave on the right
Posts: 551
Default Re: Edelbrock Thunder 1806 on stock 392

That carb is a square-bore carb.
Does your engine have a square-bore intake manifold?
In '74 & '75 IH put spread-bore Carter Thermo-Quad carbs on the pickups & Travelalls & Scouts.

The 1806 is an AVS (Air Valve Secondary) design. It is very tunable.
The secondary air valve on these almost always need to be adjusted. You need a T15 Torx screwdriver for this. They need to be adjusted to suit the weight of the vehicle. Opening too early causes the 'bog'. A simple adjustment fixes that issue. Mixture needles and springs can be changed to adjust the carb mixture.
Spend a few minutes on the Google Search and you should be able to download the Edelbrock manual for your carb.

Edelbrock sells a tuning parts kit for the carb.
Read the manual and tune the carb to suit your engine/truck and you should be satisfied.

This is assuming the fuel system is clean and you are getting fresh fuel to the carb. You didn't mention if the truck sat unused for a long period of time. If it did, the fuel system may need to be cleaned and flushed. Carb may also need a cleaning/rebuild.

Photos?

Another tip: If you have the spread-bore intake manifold, you must use the proper Adaptor. An "open center" adaptor is not recommended. If you use the wrong adaptor, you will have issues.

Also, stock mechanical fuel pump is adequate for the carb. If you have an electric fuel pump, do not go over 6.5 psi fuel pressure. Mechanical pump puts out around 5.0 to 5.5 psi, which is good for most carbs. No need for electric fuel pump in your situation.
__________________

My Junk --> 1975 "200HD" AWD Truck
My Cave location --> Western North Carolina

Last edited by 1975IH200; 11-01-2018 at 09:09 AM.. Reason: Typos fixed.
1975IH200 is offline   Reply With Quote
Old 10-31-2018, 08:18 AM   #3
robeastunder
Junior Member
 
Join Date: Feb 2016
Member Number: 8101
Posts: 18
Default Re: Edelbrock Thunder 1806 on stock 392

Quote:
Originally Posted by 1975IH200 View Post
That carb is a square-bore carb.
Does your engine have a square-bore intake manifold?
In '74 & '75 IH put spread-bore Carter Thermo-Quad carbs on the pickups & Travelalls & Scouts.

The 1806 is an AVS (Air Valve Secondary) design. It is very tunable.
The secondary air valve on these almost always need to be adjusted. You need a T15 Torx screwdriver for this. They need to be adjusted to suit the weight vehicle. Opening to early causes the 'bog'. A simple adjustment fixes that issue. Mixture needles and springs can be changed to adjust the carb mixture.
Spend a few minutes on the Google Search and you should be able to download the Edelbrock manual for your carb.

Edelbrock sells tuning parts for the carb.
Read the manual and turn the carb to suit your engine/truck and you should be satisfied.

This is assuming the fuel system is clean and you are getting fresh fuel to the carb. You didn't mention if the truck sat unused for a long period of time. If it did, the fuel system may need to be cleaned and flushed. Carb may also need a cleaning/rebuild.

Photos?

Another tip: If you have the spread-bore intake manifold, you must use the proper Adaptor. If you use the wrong adaptor, you will have issues.

Also, stock mechanical fuel pump is adequate for the carb. If you have an electric fuel pump, do not go over 6.5 psi fuel pressure. Mechanical pump puts out around 5.0 to 5.5 psi, which is good for most carbs. No need for electric fuel pump in your situation.
I will check adapter and get some pics up, fuel system has been cleaned but i have not yet tackled the carb which i am sure probably needs a good cleaning, the AVS adjustment was next on my list, and the PO got rid of the mech pump and installed an inline electric pump so i will check the specs on that. I really appreciate the feedback. On a funny note, the PO had the vac advance plumbed to a random bolt hole so at least I got that sorted to the correct port.

Thanks,

-Rob
robeastunder is offline   Reply With Quote
Old 10-31-2018, 01:16 PM   #4
1975IH200
Senior Member
 
1975IH200's Avatar
 
Join Date: Dec 2008
Member Number: 731
Location: 3rd to last cave on the right
Posts: 551
Default Re: Edelbrock Thunder 1806 on stock 392

Since your vehicle has an electric fuel pump, installation of an Edelbrock p/n 8190 adjustable fuel pressure regulator may be useful.
__________________

My Junk --> 1975 "200HD" AWD Truck
My Cave location --> Western North Carolina
1975IH200 is offline   Reply With Quote
Old 11-01-2018, 05:03 AM   #5
robeastunder
Junior Member
 
Join Date: Feb 2016
Member Number: 8101
Posts: 18
Default Re: Edelbrock Thunder 1806 on stock 392

It looks like a cheap Edelbrock mini pump, ill get a pic tomorrow, i think there are two models, one that does 1-3 psi and one that is 3-7 psi, so in theory i may be ok, here is a pic of the carb base, looks like an adapter is there of some sort, will dive in more once it stops finally raining in NH.
Attached Images
 
robeastunder is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -8. The time now is 12:01 AM.