MC 2150 question

[C dubya]

This is not in my CJ, but I figured I would get more looks here....I did the team rush and new 2150 on my 87 Wagon with 360. I am having some hesitation issues. Timing seems great, engine pulls harder than it ever has, but I have to apply the throttle steadily or it will hesitate. If I floor it it will choke out. I have not adjusted the mixture screws or messed with the accelerator pump. I think it is running pretty rich, I have never adjusted a carb personally so I am looking for any help I can get. I ordered a VAc guage from Jegs last night, should get here friday. Thanks in advance.

 

[tarry99]

This is not in my CJ, but I figured I would get more looks here....I did the team rush and new 2150 on my 87 Wagon with 360. I am having some hesitation issues. Timing seems great, engine pulls harder than it ever has, but I have to apply the throttle steadily or it will hesitate. If I floor it it will choke out. I have not adjusted the mixture screws or messed with the accelerator pump. I think it is running pretty rich, I have never adjusted a carb personally so I am looking for any help I can get. I ordered a VAc guage from Jegs last night, should get here friday. Thanks in advance.

First thing "Timing seems great" what is that all about? Put a light on it so you know............also check to see if the vacuum or mechanical advance is working. Check the flow at the accelerator pump, look in while its running and crack the throttle........Also is your choke blade fully open when running? Check your fuel filter and air filters...and if you have a gauge check your fuel pressure at the carb.........Sounds air related but could also be fuel.......Float levels, vacuum leaks, timing, starving for fuel / vent at tank or cap!
If that carb is new or rebuilt I would check all of the settings from top to bottom , they hardly ever run perfect right out of the box! Giving advise for tuning a carb from a computer screen is a pretty tough task!.............Plenty of good DIY info on the web for the Motocraft 2150 series carb with pictures ......check it out!

 

[IOPort51]

what he said.

 

[C dubya]

Thanks guys. To clarify about the timing. I have gone over and under my engine trying to find the timing degrees from what I have seen in pics, and have been unsuccessful in finding them. I really don't understand that. So my timing has been based on ear and performance. It has been slightly advanced past the stock setting, I do know that much. I do have a tach on my timing gun and have been using it to work on the timing. I have not pulled plugs and cranked, this is as far as I have gone. I have been reading stuff on the web about tuning the carb, but the only things I have really seen sugested are adjusting the mixture screws. That's as far as I have gotten. Thanks for the input,

 

[Jimbos76cj]

I second the check your mechanical and vacuum advance. IF the vacuum advance is not working right when the throttle is mashed the motor will stumble until the mechanical advance starts to kick it.

 

[Peanut Butter]

Timing marks are located on the upper to middle driver's side of the engine. The crank pulley has a mark in it to indicat top dead center of the number one piston. Some timing marks are just a small plate that is attached to the engine. Yours may be missing. Not 100% sure on the 360. Rod

 

[C dubya]

Thanks guys, I found the timing marks after I had to remove the altenator. They were behind it, I would have never found them. It seems its going to be a steep angle to shoot the light on it and see correctly once the altenator is back in.

 

[Hedgehog]

My 360 is a bear to see the timing marks. My 360 has an AC pump stacked on top of the altenator with the heater hose weaving it's way between the two. I use Yellow crayon to fill the timing mark and red finger nail polish to mark 0 degrees TDC. My timing light has an advance dial. So I set my advance on the dial, unplug and plug the vacuum advance line, then fight for a proper angle to get the light on the marks. It can be done, not easily, but it can be done. You could be over advancing the timing when the mechanical advance does it's thing. Not likely, but maybe. You'd hear the engine pinging pretty bad at that point.

 

[C dubya]

Alright, I haver rechecked the all plugs and wires. I used a grease pen to mark the groove on the harmonic balancer and have timed the motor to be advanced 9 degrees. I am still having problems at lower rpms with what seems like the carb choking out. Once I have her going 35 miles an hour or so I can start to give it quite a bit of throttle and takes off. But from a dead stop or just rolling if I give it more than a quarter throttle it chokes and dies. Suggestions where I should look next?

 

[C dubya]

I got some time this weekend to try and tune the carb. Can some one tell me everything I should check?

 

[harleydragon]

sounds like you may have a vacuum leak..as far as adjusting the idle mixture screws..usually 1 1/2 turns out is a good place to start..then with a vacuum gauge adjust the idle mixture screws out the least amount to get the highest vacuum..in other words,if the highest vacuum is achieved at 1 1/4 turns out but then stays the same at 1 1/2 turns out then set it at 1 1/4..once the throttle plates in the carb open then that overrides the idle mixture circuit..with the engine off,and breather removed,work the throttle by hand while looking in the carb to make sure you are getting good strong streams of gas through the accelerator pump

 

[C dubya]

Thanks Harleydragon, I will give that a go. Appreciate the input.

 

[Hedgehog]

Years ago I had a similar situation with a Jeep I bought from a friend. He had installed a Holly Carb. on an Iron Duke. The jeep would run well, but sometimes when you hit the gas it would shudder and all but die. We fiddled and fiddled with that carb. nothing worked at all. In the end I bit the bullet and took it to a carb. expert the problem ended up being a problem with the power valve circuit in the carb. Occasionally when the gas was hit the power valve would dump a bunch of gas in the manifold. I took it to a carb. guy, one of the cheapest best repairs I've ever done. I think it was $25 and the crappy Holly carb. turned into one of the best carbs I ever used.

 

[harleydragon]

Years ago I had a similar situation with a Jeep I bought from a friend. He had installed a Holly Carb. on an Iron Duke. The jeep would run well, but sometimes when you hit the gas it would shudder and all but die. We fiddled and fiddled with that carb. nothing worked at all. In the end I bit the bullet and took it to a carb. expert the problem ended up being a problem with the power valve circuit in the carb. Occasionally when the gas was hit the power valve would dump a bunch of gas in the manifold. I took it to a carb. guy, one of the cheapest best repairs I've ever done. I think it was $25 and the crappy Holly carb. turned into one of the best carbs I ever used.

yeah,I had an 87 wrangler AMC 258 i6 / 4.2l with a holley..I really liked it too

 

[Peanut Butter]

At the top of the page is a link to "DOCS". Go there and find lots of pdf's on the 2100 and 2150. Rod

 

[C dubya]

Thanks PB, I think I may have found some things I over looked already.

 

[C dubya]

Well I went home last night after a social event and decided to try some stuff. Checked my two vac hoses, rechecked timing, then used a plug kit I had bought and plugged every freaking smog devise or open tube I could find on the motor. Result was a 98% normal driving Jeep. I am going to hook up the vac guage this afternoon and adjust my mixture screws and I think that will eliminate the last of the hiccups. At least thats what I am betting on.

 

[harleydragon]

Well I went home last night after a social event and decided to try some stuff. Checked my two vac hoses, rechecked timing, then used a plug kit I had bought and plugged every freaking smog devise or open tube I could find on the motor. Result was a 98% normal driving Jeep. I am going to hook up the vac guage this afternoon and adjust my mixture screws and I think that will eliminate the last of the hiccups. At least thats what I am betting on.

cool..I knew it sounded like a vacuum leak..people throw a lot of money at these jeeps trying to get them running right when it's just a vacuum leak..glad you found it