i have a 76 vett with a new holly 650 on it. sometimes it idles fine not high not low but other times it seems like it is revd up a lil more. its harder to stop when braking and im not sure why this is doing it.can someone answer that for me. also 1 other question my temp gauge is reading about 230 degrees but today after a 10 minute drive home i parked it and i heard a splash. i looked under the car and there was a puddle of water. i couldnt really tell where it was coming from but the car didnt seem to be overheating. is 230 degrees to hot for the engine to run? any help on these 2 issues would be great.

 

Erratic idle can be caused by timing problems, vacum leaks, a carb in need of rebuilding, ect. You have some testing ahead of you. Check the easy stuff first, put a timing light on it, see if its eratic. It will go up if the engine speed goes up due to the advace mechanism, but this should be smooth. If the timing bounces around, the distributer could be bad, but not neccessarly so don't jump to conclusions. A simple check for vacum leaks is to remove the air claner and with the engine warmed up and idleing, cup your hands over the carbs intake covering it almost compleatly. If the engine speeds up, you have a vacume leak. If all this checks out ok, we'll go from there.

 

yo godfather, i forgot to say its a brand new holley carb just got it a month ago.

 

Thats good, it will help narrow it down. Investigate the water leak more also, they can be connected. The temps a little high, but can be conected to a leak. A leak allows water out which lowers the volume, which decreases pressure due to more air, which causes boiling, which causes more air and cavitation, it's a visious cycle. Or, the easy thing, hopefully, is your rad cap went south, and the leak is just the overflow tube. The other thing is the cooling system is just not strong enough (which would cause the rad cap to reach its capacity due to the higher temps), but since this is a new, and I presume sudden problem it is unlikly. That sort of thing creeps up a little at a time. Do more digging, we can help more with more details.

 

yo ghost, i bought the car a year ago but have been working on it ever since.i bought it from tennessee and on the way back to alabama it started overheating and coolant started shooting out the hood and water or coolant started pouring in the passenger seat. i got it towed back home and the first thing i did was put a heater core in what a PITA. i am not a mechanic nor have a ton of money so i am really just now driving this. i thought for some reason the heater core wouyld solve the problem but now that im driving it i think its something else. ask me some particular questions so i can anser them and maybe give u a better idea of wats going on. thanks for replying to my posts

 

OK, there has been overheating issues. Remember how I said they can be connected? It goes both ways. If things are running hot, things start to warp, deck surfaces, intake manifold surfaces, clearances between parts, the list goes on. The hotter it gets the worse. Don't worry though, 230 is a little high, but not terrible, new cars run up to 210 or so now to help with emissions. But they have sensors and a computor to keep them on the edge without going over (hopefully), as well as a other things to combat the extra expantion, differant gaskets, fasteners, even the way they are designed. Our older engines aren't as forgiving. What this interconection means is as things get hotter and warp, you can be getting a vacume leak, or your distributer shaft is binding or moving in relation to the cam gear and throughing off you timing, or any number of other things. As for going the other way the carb issues can cause the overheating also. Bad timing can cause overheating, as can a bad air/fuel ratio. In you case though, it is likely the overheating is causing the carb issues, or they are coincidental. Do those tests I mentioned earlier, and be very observant of the temp, and try to get your hands on a hand held temp gauge (the infrared kind, with laser are best), or anything you can, to verify the accuracy of the cars temp gauge. I will add though, since the temp issues are suspect of the carb's problems, do those test's cold, warm, and a little hot, but BE CARFULL of the hot test, both for the car(we don't want add to the problems), and for YOUR own safty, you don't need the car 230, 200 is fine. Let us know how those go and any other observations. If you have any more questions, either someone else will assist or I will tommorrow, I'm on the east coast and am going to bed soon.

 

I suggest you correct your cooling system problem first. You don't want to overheat it while you try to solve the idle problems and you will need to run it to do that. Make sure your heater hoses are good, pull the thermostat and drop it in a pan of water on the stove to make sure it opens before the water boils. Replace if it doesn't open. Check the front of the radiator for obstructions and top off the coolant while running the engine to reduce chance of air in system. When you crank it you can use a thermometer for a bbq grill to get a reading on the water temp. Not fancy but it will give you an idea of how hot the water temp is while its running. If everthing is functioning properly it should idle at 200 or less. That's just my thinking. All this will allow you to run the car and figure out the carb or vacuum issues. Get the cooling done first then start on the rest.

 

The only reason I say test a little now is because the erratic idle issue is an intermitint problem. I prefer to see the conection, if there is one, first, but you are correct, it is not neccessary, and in this case, probably a little safer for someone with less experiance. If there is not a connection, though, he may fix the cooling, and not have a problem with the carb for a while, think it's fixed, but have it return later. And he said earlier it is bad enough that he has trouble slowing/stoping the car.

 

Just my dos centavos, but I get worried when the temp hits 200. I don't want mine going over 190.
Also, you said you heard a splash, check you water pump also, it may have given up the ghost.

 

200 probably would worry me too but it is not going to harm anything at all. I don't know how much, but pressure in the radiator raises the boiling point of the coolant, right? I used the 200 figure because I don't know what temp. thermostat he is running so basically, if it does'nt boil the water out while its idling he can proceed to his other problems.

 

IMO 230 is getting too hot.

 

230 is to hot. I would solve the heating problem first and the the idle problem.