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Hard start when warm/stalling


JWray707

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Often an owner says running hot but this is just that they think or expect. Not saying you are wrong but what makes you think it's running hot? I've seen pages go by and then find out a 'problem' is actually something quite normal. Anywhere in the run range is safe but about half way in the run range is normal. If it normally runs about half way and then begins running higher it may be an indication that something has changed. Summer driving may run a little higher.

 

 

Some things that may cause warmer than usual running...

 

Is the heater hose from the rear of the head by-passing the heater and connected directly back to the lower rad hose? Block the flow or fix the heater which has a shut off in it.

 

Drain a couple of quarts out of the rad to expose the tops of the cooling tubes inside the top tank. Take the rad cap off and look. Are they crusty with dissolved minerals like the inside of an electric kettle? A crusty rad will not transfer heat properly.

 

Feel the lower rad hose.  They may look OK on the outside but rut from within and become soft. Whatch the lower hose while you rev the engine. Suction from the water pump can collapse the lower rad hose.

 

Do you have a fan shroud? It increases fan efficiency.

 

Engine off. Turn the fan blades by hand. There should be firm but smooth resistance. You should not be able to spin the blades... only turn them. The looser the clutch fan the more it will slip and the less air moved through the rad.

 

Retarded timing dumps huge amounts of heat into the exhaust ports and from there into the cooling system.

 

Yeah, when I say running hot I just mean it's running hotter than it was before I swapped the carb. I guess I won't worry about it until it starts reaching the H. (Have had bad experiences in the past with overheating on different cars and ended up doing some damage, so maybe im just being paranoid.)

 

Heater doesn't work so guess I can block that hose off or fix the heater.

 

Just recently drained the radiator partially to install the new thermostat, looked in the radiator and it looked clean, though the coolant was pretty dirty. Last owner said it was newly installed rad.

 

Lower hose is soft and should probably be replaced but is not collapsing when revving.

 

No fan shroud...maybe a future investment.

 

Fan blades seem fine. Firm but smooth resistance.

 

If anything I would think my timing was advanced, was turning dizzy counter clockwise to set timing.

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TimingTabs03.jpg

 

Each point is 5 degrees, each notch between is 2.5 degrees. For 12 degrees you need the first notch on the downward side of the 10. Actually you would be at 12.5 but....

Good to know, each notch is 2.5 degrees. Thats where its set, right on the other side of 10. I will hookup the new plug wires tomorrow to see if that helps the light flash more consistently and try to snap a picture of it too.

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So don't know exactly what temp.? Is your gauge 1/2 way, 3/4 way? What's your tstat temp? What part of USA are you? It has been hot in CA lately which can affect your temp.? The reason why I was asking for you to post pic of TDC, wanted to make sure u have a good base. I never had a radiator shroud on mine, tstat is 165, and when its hot like 95 degrees, on the freeway, I'm at 175 or at a stop light for a period of time. Besides if timing is retarded, if you are running to lean it can also run hot. You in Cali?

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Forgot to mention, you can check more accurate temp. By getting an infrared thermometer or cheaper route get a thermometer, the kind that you check the temp., with meats and put it inside the radiator and see what the temp. Is after idling for like 15 minutes or so. You may have to take out some coolant, just enough, so that it does now spew out. Good luck.

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So don't know exactly what temp.? Is your gauge 1/2 way, 3/4 way? What's your tstat temp? What part of USA are you? It has been hot in CA lately which can affect your temp.? The reason why I was asking for you to post pic of TDC, wanted to make sure u have a good base. I never had a radiator shroud on mine, tstat is 165, and when its hot like 95 degrees, on the freeway, I'm at 175 or at a stop light for a period of time. Besides if timing is retarded, if you are running to lean it can also run hot. You in Cali?

Gauge is reading 3/4 normally and rises when I'm riding the throttle. Hasn't quite reached the top (H) though.

Where is the best place to get the temp reading from? I have a meat thermometer and a infrared one. What would you suggest?

I'm in Northern California where it gets in the high 90's almost everyday during summer, Lake County.

 

I DO have a timing tab and yes, there is a small white mark on the pulley.

 

I will check exact temp tomorrow and share it.

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The small white mark can be zero or tdc or 12, we don't know for sure. This why I said get a base line of tdc or zero degrees. If zero or tdc, your dist. Rotor should point towards # 1 spark plug wire and the 2 cam lobes should be pointing at 10 and 2 o'clock. Both procedure will require that you take off dist. Cap and valve cover. Regarding reading the temp., you can aim the infrared thermometer on the radiator itself, I think they come with instructions, or you tube it. With plain thermometer, placed it inside the radiator. But take the rad. Cap off and do this first when cold, then let it idle for like 15 minutes or so.

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Not saying your head gasket is bad but hainz or banzai510, he's here on Ratsun, and his YouTube videos has a lot of tutorials about the L series engine from making sure its at Tec to head gasket, so on. Maybe he can chime in or keep on searching YouTube for the specifics you are looking for. Watching his videos over and over again and getting help from other retainers like datzenmike gave me a better idea.

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Just an update, replaced the spark plug wires this morning. The hesitation seemed better but it's still slightly there.

Drove it about 2 miles on the highway and the temp was fine...stayed under 1/2 and didn't creep up.

No hesitation at higher speeds, only from a stop or when barely taking off.

I'm going to just work with driving it with the hesitation until I can have someone with more experience/tools tune the carb so that it's spot on.

The smog guy in town is an old timer and I'm sure knows his carbs and probably can dial in the afr perfectly. May even have a AFR gauge, if I'm lucky.

Thanks again for all your help everyone. Glad this resource exists!

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Electrical hesitation

My hesitation was a hard to see crack in the coil tower. Only happened just above idle when letting the clutch out. Spark would jump to negative terminal.

 

Fuel delivery hesitation

Engine off, look down the carb on a warm engine and pump the throttle as slow as if you were driving it. You should see a small squirt of gas shoot out into the primary barrel. Generally the slower you step on the gas the less fuel squirts out so this may not be the problem. You could turn the idle mixture richer and see if this changes and put back after.

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Yesterday I pulled off the valve cover and checked the valve clearances and they all seemed correct. Cold measurement intake-0.008 exhaust-0.010. While I was there I also was able to get the crankshaft to TDC via the notch and dash alignment. (Thanks hainz for the youtube videos!) Checked the timing again and it turns out that little white mark on the harmonic balancer was a notch and it was lined up perfectly at 12. Remarked it with a paint pen for the future.

So, timing is correct for sure.

Thinking the hesitation has something to do with the carb. Clogged jet, accel. pump, throttle cable, correct tuning? Still need to read the plugs for AFR.

The truck is an automatic, just making sure I know the procedure...I drive it (preferably at higher speeds) until warm and then pull over with it in nuetral, get out and pull one of the plugs to read it.

So, I shouldnt put it in park?

The engine should be off, correct?

And it will give a better reading if im actually driving it and not just letting it idle?

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Yes, engine should be off when taking off spark plug, be careful hot!. When you checked the valves for clearance and on TDC, did you check the front 2 cam lobes to see if its at 10 and 2 o'clock, while your distributor rotor is pointing towards #1 spark plug wire, this is How u know if u are at TDC. Then look at where your timing tab is pointing at and this should be zero degrees, did you do this?

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Engine should be off and yes put it in park. Kindy ocd but I drive it around town for about 5 min, pull over, check the plugs, drive to the freeway for about 5 min. Then pull over at street not freeway and check plugs again, usually color is tannish, brownish color, if its black, metal part of spark plug, running rich, I also make sure rpm at idle is around 800.

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Took valve cover off again and had the truck in drive. Turned balancer until two front cam lobes were at 2 and 10 this allowed the notch and dash to line up and also set that white mark on the balancer to "0" on the timing tab.

 

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The only thing that was wrong was the distributor rotor was not pointing toward #1 spark plug.

 

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What to do now?

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