Former member, back again under a new name, with a carb question - JeepForum.com

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post #1 of 4 Old 08-29-2016, 07:01 AM Thread Starter
cgebs69
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1987 YJ Wrangler 
 
Join Date: Aug 2016
Posts: 2
Former member, back again under a new name, with a carb question

Howdy everybody. Been a long time. I was formerly known as Rproject, but for some reason I can't get that username to work anymore. So I'm back, with username cgebs69.

I have an 87 Laredo with a fresh 4.2 in it. My previous 4.2 gave up the ghost last year and for a multitude of reasons, a new motor wasn't able to be put in to my rig until now. Here's what was done:

- new HEI distributor
- donor intake/exhaust manifold from an 86 4.2
- donor pulleys and brackets from and 86 4.2 in order to delete the a/c compressor
- wiring clean up from previous nutter bypass and ICM/ECM delete with the new distributor
- migration of MC2150 from my motor to the new 4.2
- oil pan from donor 86 4.2 (mine had a hole in it from the rod that it threw last year. LOL)
- New belts, hoses, plugs, wires (8mm)
- timing to 9 degrees

So here's the deal. My mechanic got it running. Beautifully. He drove it 15 miles to my place. I drove him back to his. Everything was good to go. Ran a few errands including a bath for the Jeep, fresh gas and a few other things. Still, all good. Went out for a gentle run in the country to stretch its legs after sitting for a year. After about 45 minutes and 40 miles, started to get a hesitation when turning. Then a hesitation when giving it gas. Had to double tap the gas pedal to keep it from bogging down. Died on me a couple times. One time I couldn't get it to restart. My buddy dragged it back to my mechanic's with me. He jumped on the gas pedal a couple times and it started and has started without touching the gas pedal every time since, BUT, it's still hesitating and wanting to die on turns. Only right hand turns, though.

My mechanic has opened up the carb and the float is working. The bowl is about 1/2 filled with gas. When the throttle is operated, it's squirting gas just fine. Pretty stumped at this point as to what is causing the starvation. Fuel? Air? Spark is definitely good. Fuel pressure is at 10psi. Fuel filter is clean as a whistle.

Thoughts from my carb brethren? Thanks.

Pic is of my rig. One of my favorites. It was taken by my, then, 11 year old daughter at The Badlands in Attica, Indiana.

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post #2 of 4 Old 08-29-2016, 07:37 AM
Chrisnvegas
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1992 YJ Wrangler 
 
Join Date: Dec 2012
Location: The Desert
Posts: 5,199
Welcome back!

You want 6 to7 psi.
I have the float adjusted to .875" wet.
The float level needs to be precise.
The wet fuel level must be higher than the power valve. I use this for checking wet levels.

http://www.harborfreight.com/6-inch-...ler-93684.html

The motor must be warm at idle when the air horn is removed and measurement taken.
After each measurement, the air horn must be replaced (don't need to re-screw it though) and again removed, then next measurement taken.To adjust level, the needle tab is carefully bent.

Not sure why you have a regulator.
If you use a proper quality mechanical pump (I run a $50 Carter) with the right filter and return (keeping the return higher than the carb intake) the regulator is just an extra unnecessary part.

Timing:

I also have the CRT HEI and fresh rebuilt 258.
Timing is closer to 10* advance and the vac advance was also adjusted.
It had a hesitation at 8*.

It's a screamer now.
No dead zone and happily revs to redline.

Vacuum leaks really throw the whole thing off and are easy to miss.
I double checked with a can of starting fluid & found a slight intake leak. An extra 1/2 turn of the intake bolt took care of it.

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post #3 of 4 Old 08-29-2016, 07:40 AM
Mr.B
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1994 YJ Wrangler 
 
Join Date: Nov 2005
Location: Roseville, Ca.
Posts: 4,435
Not a carb guy, but do you have a dent in your gas tank skid plate? That would happen to me, until I got a new skid plate.

By the way, you should PM one of the mods here. They can help you with getting your old name back. We had a security breach a while back.

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post #4 of 4 Old 08-30-2016, 06:20 AM Thread Starter
cgebs69
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1987 YJ Wrangler 
 
Join Date: Aug 2016
Posts: 2
Quote:
Originally Posted by Chrisnvegas View Post
Welcome back!

You want 6 to7 psi.
I have the float adjusted to .875" wet.
The float level needs to be precise.
The wet fuel level must be higher than the power valve. I use this for checking wet levels.

http://www.harborfreight.com/6-inch-...ler-93684.html

The motor must be warm at idle when the air horn is removed and measurement taken.
After each measurement, the air horn must be replaced (don't need to re-screw it though) and again removed, then next measurement taken.To adjust level, the needle tab is carefully bent.

Not sure why you have a regulator.
If you use a proper quality mechanical pump (I run a $50 Carter) with the right filter and return (keeping the return higher than the carb intake) the regulator is just an extra unnecessary part.

Timing:

I also have the CRT HEI and fresh rebuilt 258.
Timing is closer to 10* advance and the vac advance was also adjusted.
It had a hesitation at 8*.

It's a screamer now.
No dead zone and happily revs to redline.

Vacuum leaks really throw the whole thing off and are easy to miss.
I double checked with a can of starting fluid & found a slight intake leak. An extra 1/2 turn of the intake bolt took care of it.
Thanks, Chris. Life threw me sideways for a while, but I'm back on top.

I don't have a regulator in the system. My mechanic put a pressure tester on the inbound fuel line, before the filter, and that's how he got the measurement. As for the other items, it makes sense to me. I'll be back at my mechanic's in a week or two and will have him check into the tweaks.
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87 YJ 2.5" suspension, 1.5" body lift
Built to do what I need it to do
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