Those are definitely better numbers.

Next I'd check to see if you have a plugged exhaust. Is there a cat on it?

 

No cat, and the muffler was replaced about a year ago. It revs fine, and runs great at idle and on the flat. It even runs fine going up a steep hill - it just won't hold speed now. I am having a hard time keeping the choke open after warm in this cold weather.

 

So your choke keeps closing from the cold weather?
It sounds like your engine bay is getting too cold. Have you tried putting some cardboard over the grill to keep the icy air from chilling everything down?

 

If the choke isn't staying open like it should, that would be a good canidate for the power loss you describe.
If the choke is electrically heated, make sure the connector is plugged in and getting proper voltage.
If it is just heated by the choke stove, insure the stove tube is still attached at both ends, and isn't plugged. Air must be able to flow thru the tube, in order to heat the choke thermostat fully.

 

Did the stock air filter have a provision to bring exhaust manifold heat into the air cleaner? I'm not familiar with carb engines so I don't know, but if it did, your carburetor may be icing up. I had a VW that did this because the carb heater was disconnected. Iced up carb would account for revving freely when stopped because the ice melts quickly at idle.

 

It had a little of both. The exhaust manifold bolts directly to the intake manifold to use the heat from the exhaust to prevent carb icing. If he still has the stock intake and exhaust, this still exists.

However, it's possible that the spring in it is not working, or is seized shut. Hadn't thought about that. If it's stuck closed, the exhaust won't warm up the intake.



Other than that, the air cleaner had another provision that brought warm air from around the exhaust manifold and put it into the intake to take the sharp chill out of the cold air.

 

I do have an electric choke. I check the voltage and it is 12V. The choke works, but it doesn't get warm enough (we have had -5 to 25 degree weather for three weeks now) for the choke to fully open unless I set the choke way lean (then I have to remember to reset it in the morning so that it will start).

The original air cleaner assembly had a warming port coming from the EGR spacer (the EGR, warming port, and pipes have been removed and plugged - this has not hurt drivability other than the warming aspect in cold weather). To help the choke out I installed a heat tube from the exhaust manifold to the choke assembly this afternoon. It seemed to help the choke open and stay open in a reasonable amount of time with the choke set one notch on the rich side. How this will affect the choke during the summer will be interesting, but it is easily removed. This just may be a cold weather fix. I will see in the morning and if it helps with the power issue.

You mentioned a "spring". Are you talking about the choke spring, or something else?

 

The sharp chill can cause icing. I think one reason to have warm air pulled into the top of the carburetor is to prevent icing. CJ77F100, do you have the old aircleaner & heat stove duct to put back on during the winter? Having warm air at the top of the carb would probably help keep the choke warm and open too.

 

The spring is the heat riser. It's located below the carburetor between the intake and exhaust manifolds (right where they bolt together). When the engine's cold, reach down under the carb and feel around on the exhaust manifold. There should be a steel weight towards on the side towards the firewall. It should swing and move freely. If it does, feel to be sure the coiled spring is there too.

If it's seized, try spraying it down with penetrating oil and get it to move freely.
If the spring is missing, you'll need to replace it to restore proper warming.

Either way, if the heat riser isn't working correctly, your carb will have heating issues.

 

Here are a couple pics of the heat riser AB is refering to. They show it closed and open. This manifold is missing the thermol coil which operates the valve based on exhaust manifold heat.






HTH
Jim

 

The heat tube to the choke seems to have fixed the choke issue for the cold weather. The choke now comes off like it should. However, I am still having the power issue on steep inclines. I can't maintain 60+mph when before I had to problem at almost any speed (within reason ) I never noticed a heat riser before - I will definitely check once my motor cools down.

 

Well I got it figured out! After all the checking and double checking of compression, spark, gap, timing, exhaust, choke (including heating issues) - it ended up being a vacuum leak at the carb to intake area. WOW don't I feel stupid! Oh well, at least I know that just about everything on the motor is good!



By the way, for good measure I was thinking of using some Seafoam to clean up some internals. Has anyone used this, and what was your experience? Thanks for all of your help guys!

 

aslo forget those factory timing setitngs. run as much timing as you can with your normal load and normal fuel you are going to run. It will run better this way.
Ithould also run better with the stock air cleaner in the winter but all of needs to be there and working properly.

 

Gas quality

 

Very true! The winter gas around here is not good - but we pay more for it! haha figure that one!