Poor performance on a 1960 CJ5, F-134...

I've inherited a 1960 CJ-5 and am in the process of trying to work out all of her problems. lol I found that she had a bad head gasket & a chipped and cracked #3 exhaust valve. I have made the repairs (myself) and took her on a trail ride with my jeep club here in Ocala, Fl. Problems that still plague me are;

1: A loping condition while idling. Yes, it is a Carter 938 SD carb.

2: Installed '3' spacers on the fuel pump (with the glass bowl & vacuum) to stop the backfiring & now do not have enough vacuum to operate the Trico wipers. They worked before I installed the spacers. And I still have too much fuel pressure, like 4-1/2 psi.

3: The ignition only makes a clicking sound when attempting to start her now (I have a good battery).

4: My vacuum gauge won't pick up a reading while hooked up to the intake manifold fitting and it seems weak when I put my finger on it.?

I want to keep her as original as possible and to replace with newer stuff like fuel regulators, electronic ignition and such is out of the question. It ran before, there's no reason why she can't run once again!

There seems to be a lot of experience here as I have read a lot of threads. Perhaps we can keep her from being dumped back into the barn...

 

Basics first.
Check the valve adjustments-intake and exhaust.
Perform compression test....got to have good compression
Perform leakage test....no more than 10% per each cylinder...either thru the rings or valves.
If all those adjustments and readings are acceptable/within tolerances,
then move on to fuel and ignition systems.

 

1) Check for loose fitting throttle shaft.

2) Adding or removing spacers should not effect the fuel pressure.
Fuel pressure is internally regulated via the check valves.

3) Likely it has a bad solenoid or perhaps just a very poor connection.
See: http://www.earlycj5.net/forums/showthread.php?107472-NORS-starter-switch-and-solenoid

4) Exactly where is it hooked up ? Could be bad valves or valve timing if the vacuum is low.
Also could indicate very low compression.

 

Compression tests show;
#1- 125
#2- 125
#3- 130
#4- 130

Fuel pressure is regulated by how much of the fuel pump arm is being manipulated by the cam. The further away the less pressure. These 3 spacers have taken the fuel pressure from 5-1/2 lbs to 4-1/2 lbs. and I lost my wipers in the process. Timing is set at 5 degrees BTDC. I can occasionally get it to idle smoothly but put her under some stress and she goes back to loping with a high idle. How do I know if the check valve off the side valve plate needs replacing? Right now I need to get her past not wanting to start...

 

The fuel pump and the vacuum pump are all in the same assembly, so if you space it out to reduce the fuel pressure, you are also spacing out the vacuum pump and thus reducing your vacuum "pressure".

Edit: Additional thought - I would take the spacers out and that would restore wipers. To reduce fuel pressure, I would do some thinking on fuel line manipulation, ie larger tubing.

 

Too much fuel pressure causes the backfiring through the exhaust but the wipers work. There has to be a consolation here somewhere...?

 

You may have responded while I was editing previous post. I would do some thinking on fuel line manipulation, like making the tubing bigger, or a combo of sizes. Small from the pump up to the top, then bigger from there to carb sort of thing. I am not a hose vs. pressure expert by any means but I know that pressures can be manipulated in such fashion.

 

"4: My vacuum gauge won't pick up a reading while hooked up to the intake manifold fitting and it seems weak when I put my finger on it.?"

Are you conducting this test with all other connections (eg, PVC valve, vacuum pump, wipers,) removed? At the fitting just under the carb? Is your gauge "known good?"

The compression readings are good enough for me.

Loping sounds like an over-rich mix - maybe the float setting or valve leaking. But also check for any vacuum leak at the carb base flange gasket, the mix may be set rich to compensate for an air leak.

Actually the fuel pump arm ought to be building up pressure against the diaphragm spring, then the lever arm is more or less "idling" until there is more demand, and a drop in pump pressure.

2.5 PSI ought to be adequate for the Carter carb. Excess pressure can be reduced with a simple cheap in-line regulator. Many of us have used them.

 

And there you have it and I learned something as well.

 

That's not physically possible because the fuel pressure is regulated by the check valve springs.
The check valve springs are non adjustable.
Moving the fuel pump in or out can only effect the pump stroke.
The pump stroke effects the fuel volume and not the pressure.
Fuel pressure only effects the inlet needle/ orfice seating.
Your carburetors inlet needle should be able to handle 5-1/2 PSI inlet pressure even if the specs state a slightly lower PSI.

 

Can I get air sucked in through the throttle shaft openings? Is this a 'replacement' part that I can get a hold of?

 

Perhaps Walck's is having me regulate the volume of fuel and getting volume and pressure confused? I've stated that the carb rebuild kit was crap and most of the old stuff went back in the carb when I took it apart for a rebuild. Any ideas on where I may get a better master carb rebuild kit? The new float seat needle pin, spring & seat shut the fuel off completely...I reinstalled the old one. The low speed jet would not screw in, I used the old one...The carb to manifold gasket would not fit...like I said, it was the worst carb rebuild kit that I've messed with. 8 times into this carb and now I think my problem is this kit.

 

With engine running, spray "ether" at the throttle shaft to determine if there is a vacuum leak.

See: http://z4.invisionfree.com/CJ3B_Bulletin_Board/index.php?showtopic=4546

 

If you have no vacuum (or very low) at the base of the carb then the engine has now way of sucking fuel into it and will not run.
Concentrate on vacuum problem first.

 

I am looking for the correct method to check my vacuum. I have dealt with bad gauges in the past, it's a decent one. I have set the mixture to compensate for what sounds like a leaking carb to manifold gasket and a vacuum problem. Shall I use Permatex super high tack on this gasket and reattach? I just know my problem is somewhere in the fuel, carb and vacuum systems...I want to go play in the mud some more....with my jeep!

 

"I am looking for the correct method to check my vacuum."
Use the port directly under the carb, with no other connections.


"Shall I use Permatex super high tack on this gasket and reattach?"
Seems reasonable - especially if you already suspected a leak there, and changed the mix screw. I use the thicker non-hardening type Permatex from a tube, with a new gasket if possible. Check the bottom of the carb for warping of the flange ears, from over-tightening.

But I'd try verifying the leak if you can with the starter-fluid trick, see if the idle changes.



"The new float seat needle pin, spring & seat shut the fuel off completely...I reinstalled the old one"
There are several different needles/valves for Carter YFs and the Jeep type is specific. Not always included in generic kits. It should have a resilient or spring loaded tip and a smaller orifice (for rough country and to better resist incoming fuel pressure). Each type has a different float height specification. Sounds like you ran into that.

Search these archives, it's been discussed many times.

 

Yes and no. If the carb is very worn air will leak and maker it hard to tune precisely. The fix is re-bushing by a professional rebuilder.

But I would consider this a last resort unless wear is severe

 

I have the same engine, with a solex carb. It was badly working; I went to a specialist in Jeep, a neighbour. He checked the valves;
changed the carb, spark lugs, and some small electric parts, timing. And the engine works perfectly.
I was afraid at the beginning, engine broken somewhere, etc...
I had also a problem with idle, in fact it ws dirty inside the carb. Then perfect.

You can put some additive in your fuel so it cleans the valves better and it is perfect.

Morality : don't worry, just put new parts, tehy are not expensive, and the engine will work perfectly. It is a very strong one.