'87 Accord - Hesitates, Bucks at operating temp

[Chugga]

I have an '87 Accord, (carburated) that starts and runs fine until it warms up and reaches operating temperature. I'll be driving along and when the temperature gauge reaches a certain level you can feel the car kind of lurch (maybe when the choke is closing?). Then it seems to occasionally hesitate and mildly buck between 2500-3000 RPM in third gear. I have replaced both fuel filters but not touched the carb. I also replaced the plugs and distributor cap as well. Any suggestions?

[A20A1]

Check out this thread... check your booster venturies
http://www.3geez.com/showthread.php?t=8972

[Chugga]

Check out this thread... check your booster venturies
http://www.3geez.com/showthread.php?t=8972


Whoops, sorry. I should have mentioned that I did check the booster venturies and they were really tight. I couldn't move them at all. I'm thinking it must be heat related somehow. The coolant level is full but I'm wondering if the mixture is wrong. I just bought this car 4 months ago so I don't know what the previous owner was doing. It almost looks like it could be straight antifreeze in the rad.

[Wipeout]

As long as your temp needle stays a little below halfway up (that's where mine stays anyway) then I wouldn't worry about the coolant mixture. I had the same problem as you and it was my booster venturis. Is the carburetor getting enough fuel? Is coolant leaking into the manifold?

[train]

don't ever rely on needles and warning lights in the dash to alert you to problems. they're too generic and not always accurate. i'm new to carbs, but if the engine temp reaches a certain level (near operating temp) and then starts to buck and hesitate, your choke might not be opening like it should. there was another thread in here with someone saying the choke cable was loose. i told them that i had never seen an accord's carb, so i don't know how the choke is operated. i have only seen chokes operated by a heated bi-metallic spring. if that spring doesn't get hot enough, it won't open all the way, which could cause some hesitation once the engine gets warm. if its not getting hot enough, i would do an applied voltage test and a voltage drop test if the spring is electrically heated. if its heated from the exhaust, check the tube that runs from the exhaust manifold to the choke on the carb. if there is a hole or tear or anything like that in it, that hot air will leak out causing the spring to stay colder than it should at normal operating temperature, so it won't open the choke all the way.

if an accord's carb doesn't have the heated bi-metallic spring, disregard all that and please inform me of what it has. lol. possible :uh: on me. just tryin to help tho.

[A20A1]

The choke is heated electrically, it is held open slightly with the choke puller... the choke pulled gets vacuum from the base of the carb... as the choke is pulled open the choke opener reches a certain point that opens a secondary passage that bleeds of vacuum and keeps the choke from opening any further.

There are also ratchet type linkages on the choke that move the choke along...

I would think the choke isn's opening fully if it is a problem when the car is fully warm.

Could be other things like bad electrical connections weak ignition, weak alt output

What i don't understand is why it's only in 3rd gear.

[Chugga]

Thanks for all the replies guys. I haven't had a chance to check much out yet but I'll post back when I figure out what is happening. I will definately check on the choke assembly to see if that is the problem. I should clarify that it happens when the car is warm and running from 2000-3000 RPM. It doesn't seem to be noticeable in the higher RPM ranges. It also occurs in all gears, not just 3rd. Sorry for the misinformation but only lately have I really been paying attention to the details of the problem. Thanks again.

[accordlxi2.0]

what about the fuel filters???

[Chugga]

I did change the fuel filter near the fuel tank and also the one under the hood near the carb. Is there a third filter anywhere? What does the black canister located on the passenger side do?

[accordlxi2.0]

well there is, it's loctaed within the float screw.
if the chokes works then the car would'nt start when cold.

[A20A1]

don't worry too much about the float one... since it's such a hasstle to get out and you'll have to replace the o-rings.

The black canister is a fuel vapor collector.

You mean if the choke didn't work then the car wouldn't start when cold.

might be the power valve or accel pump problem or the float level is off or weak fuel pump.

[accordlxi2.0]

oh yea, if it was shut, dude i was busy last night.

[Michael Cote]

Sounds like a problem I had with mine. I had to run a power line from fuse box to that solinoid thing at back of carb. It would sputter at the RPM range you speak of when fully warmed-up. Worked fine when cold and under 3/4 to full throttle when warm. It took me a month to figure it out. That solenoid closes when key is turned off and/or when coasting above 20 mph when working properly. I had to hook a multy-meter to see it act up and narrow it down to the line to that carb solenoid. It's supose to be controlled by that computor under drivers seat. I just wired it with a quick-connect, fused line and on an accessary male connector on fuse box that is only energized when key is in the on position. Good luck, Mike

[Michael Cote]

Me again:
There's pictures on this 3 Geez site to find where carb solenoid is located. Let me know if you need more clarification and how you made out.