I rebuilt the carb on my 87,it does run better although the last two rides I took it on it overheated, the rides consist of about 6 miles with a bit of a hill, I was going to change the coolant and the thermostat, I wasn't going to use any radiator cleaner, my buddy suggest opening the drain cock, pulling out the thermostat, then stick a garden hose in there, turn the water on, turn the truck on, then let it run for a while, I also read about the trick of parking the truck with the front facing uphill and burping the cooling system that way.
So my questions are should I use the radiator cleaner? Should I clean the system with or without the cleaner, then burp it?
I wasn't really having any trouble with overheating before the rebuild.
Thanks


 

Check your plugs and see if you're running too lean. Verify your timing. Make sure you're still around 12° at idle. Running too low of timing will cause it to run sluggish and run hot.

As far as cleaning and flushing the coolant system, go for it. That's general maintenance that doesn't hurt to do too often. Put whatever cleaning you want to use in and run it by their instructions. Make sure your heater valve is open also. Then use the garden hose to flush the system completely. Since you're in HI the water shouldn't be too cold to use. Otherwise, I'd suggest you use distilled water to flush it out a few times. Either way, whenever you finish flushing the system refill it with distilled water and coolant or a 50/50 mix. Pull the thermostat and verify it works on your stove. If you have to replace it get an Aisin brand OEM thermostat. Lastly, just replace the radiator cap. They're cheap and it's usually the problem when it fails to hold enough pressure to stop the water from boiling.

 

Don't forget about the fan clutch.

 

Thanks Tim, what would my plugs look like if I am running lean? It isn't running sluggish
It's time to change the water anyhow.
How do I check the heater valve?
So that's 50/50 DISTILLED WATER AND COOLANT?
How do I check the thermostat?
I will need to get a cap.
Sorry about all the questions, feel free answer them or not
Thank you

 

Thanks, my understanding with the fan clutch is, if you try to manually rotate the blade it should be stiff, correct me if I am wrong, I will check that.

 

Not sure how to test the fan clutch. I'd like to know how....
However, I had an overheating issue in the past and didn't think about the fan clutch. Of course, that was my issue.
Good luck.

 

Check the vacuum advance and it's piping to the carb.

The vacuum advance should advance the timing substantially at higher revs and little throttle, as in cruising conditions.

 

This site has some good examples to look at for spark plugs...
https://www.onallcylinders.com/2012/...r-spark-plugs/

The heater control valve should be mounted on the fire wall. You want to make sure it's opening and closing via the temperature controls. If not, open it manually and verify you have hot water running through the heater coil while your cleaning and flushing.

Yes, 50/50 is premixed Distilled Water and Coolant, ready to use as is.

Remove the thermostat from the housing and tie a string onto a wooden spoon or pencil. Hang the thermostat from the string into a pot of water on the stove. Don't hang it too close to the bottom of the pan. You'll need about 6" of water. Slowly heat the water until you see the thermostat opening. Track the temperature of the water with a accurate thermometer. Preferably a digital one. It should open around 190°F for an OEM thermostat. If it's not opening 100% or taking too long, replace it.


Good call on J94's part as I forgot to mention the fan clutch, the fan, or the fan shroud. Here's a good site for the fan clutch. If you wind up having to replace the fan clutch post back up. It can be done without removing the hoses or draining the radiator.
https://www.wikihow.com/Test-a-Fan-Clutch

You can test your distributor vacuum advance diaphragms with your brake bleeder. Remove the cap and pump each one up to about 20psi separately. Watch for the mechanical advance inside the distributor to rotate. If either one fails to rotate the mechanical advance replace the distributor. They charge more for the damn vacuum diaphragms then they do a complete distributor. I just got finished replacing mine for this very reason.

 

Thanks Tim for taking the time to give me that info, guess I will just trouble shoot one thing at a time

 

Also I need to put on the fan shroud, I have been running it without for a while.

 

Okay will check it out, I was a little concerned about all the vacuum lines, I would like to scrap most of them, don't need them here, that's another project

 

Be careful removing vacuum lines. Remember, vacuum lines are not just emissions but pneumatic control. Most of those vacuum lines give your Aisan carburetor improved functionality over a standard carburetor. Things like, the choke breaker so it doesn't run too rich on cold start, The HAI (Hot Air Intake) system that improves cold weather driving (not like you have that problem in HI ), and the deceleration fuel cut.

The fan shroud needs to be installed. Without it your fan cannot pull enough air across the radiator to adequately keep the engine cool. You're lucky you live in such a temperate climate or it could have caused major problems. These trucks, with aluminum heads, can crack, warp, and blow HG's if they're not properly maintained.

 

Thanks Tim, so I changed the coolant, thermostat, put the fan shroud on and lowered the idle, I have took it up the hill a couple more times, it seems to be improved but it still gets a bit too hot on that uphill, does fine coming down, it's mostly a farm truck, I would like nail it at some point

 

I would go as far as saying it wouldn’t hurt to check your water pump. Most of the parts for the water system are inexpensive compared to rebuilding a blown motor. I had similar problems when I first got my truck. Took the electric fan off put the stock one back on with a shroud ... did the thermostat and everything and still would get warm if I got stuck in traffic.. seemed to be ok when I could keep good air coming threw it. Finally decided to pull the water pump and it only had 2 1/2 of the impeller blades and not the 5 it’s suppose to have. Assuming it didn’t have much coolant or clean water run in it before I got it. If you get around to getting rid of your unneeded vacuum you’ll be way better off swapping to a Webber carb and the truck only needs 2 vacuum lines to work at that point 3 if you hook both to the distributor

 

Okay, I will put that on the list, I know it is probably some little thing, I would like to delete some of the vac lines in the future, I will just go with it how it is for the time being

Appreciate your input