Hi Gang, new to this forum and I have an issue.

I just bought a carbureted 1986 Honda Accord Hatchback Automatic with roughly 140.000 miles on the clock that sat for two years but ran great when it was parked.

I put new plugs, air filter, oil & oil filter, in her and she starts well and runs well (while going down the road.) The problem is: at a stop, it stumbles & shudders like it wants to shut off and sometimes it does.

You have to throw the tranny into neutral and keep your foot on the pedal to keep the engine going when you come to a stop and then throw it into drive when it’s time to go. (very annoying)

I brought the car to a trusted mechanic and was told (today) that the two center cylinders compression is a little lower than the compression in the outer two cylinders and that there may be an issue with the valves.

The thing is a muffler shop that put a new catalytic convertor on also did a compression check and I was told the compression is good.

I really disagree with this assessment and I’m more prone to think that there’s either an issue with the carburetor, a vacuum line, or something much less sinister than bad valves.

I bought this car for my stepdaughter as a “college car” and I’m not dumping three grand into it to rebuild the motor.

Thoughts…………..please, and thank you……

 

What were the compression readings? I guess you could do your own compression test.

I never worked on a vehicle with a carb, so others will have to give you tips. I know there are a ton of vacuum lines, so you might want to inspect them for cracks, etc...

 

If it sat and you are not sure of the last tune up. Add the cap and rotor to at least finish that part off.

If you had a new cat installed, the old O2 might be on the list to replace as well.

Is the gas in the car the same that was there two years ago? If so, I'd try to keep it full for a bit with freash gas. Also for sitting the fuel could have "gummed" up in a few places inside the carb....so I'd suggest a can of your favorite gas/carb cleaner in the tank....and pull the screen off the top of the carb - don't drop the nuts into the throat - and go to town with some spray carb cleaner.

A three door, auto, carb'd - in 89 I know those only came as a "DX" - no power windows. I kind of like the 3rd gen Accords (86-89)

Also, there are two fuel filters on these, one under the hood right by the brake booster, the other is behind - inward of the drivers side rear wheel.

EDIT: I see PA posted as I was typing - more that a ton, more like two tons of vac lines and you check inspect them.....some of the spray carb cleaner might help find a vac leak - be careful - once the car is warm...which seems to be when the issue happens.

 

I actually did replace the cap & rotor (forgot to mention that)

Yes the gas is basically the same that was in there two years ago but it wasn’t much and I filled the car to three quarters with new gas and poured two bottles of “Heet” into the tank to soak up any condensation that may have developed.

The O2 sensor is a good thought, and as far as the carb. cleaner….. I sprayed three cans of the stuff into the carb. and cleaned it up really well, and I also sprayed it on all the vacuum lines checking for a drop in idle and it didn’t (the vacuum lines are good)

I haven’t changed the fuel filters and that’s on the list to do.

Thanks for the reply's guys.............

 

Here’s the progress so far……

Took the car into a garage that I’ve used in the past that does decent work and the first thing they did was a compression test. They got a reading of 180 on the two outer cylinders and exactly 75 on the two inners.

He didn’t go any further because he said his experience has taught him that the valves on these Honda’s are usually the Achilles heals. (1986 Honda Accord)

He suggested rebuilding the head to solve the rough idle issue, but I just can’t seem to get my head around rebuilding an engine to solve a rough idle.

The shop that put the exhaust on also did a compression check but they told me that the compression was fine.

I have to admit, I’ve never performed a compression test before, but the car just runs so good & so strong that sticking or burnt valves aren’t registering in my brain.

The new question is: is it possible to get erroneous or false compression readings, and wouldn’t true low compression in some of the cylinders cause the car to run bad “all” the time?

He suggested that I just "drive" the car to see if the valves either unstick themselves or if whatever is gumming up the carburetor – eventually loosens up.

I’m not about to rebuild a motor with only 140.000 miles on it that runs as well as this one does because of a rough idle at stop lights.

Help me out here guys, the car ran like a sewing machine two years ago before it was put up, and I’m having a really hard time believing that the mere act of just sitting for two years would destroy a few valves and cause a low compression issue.

 

Do you have a compression tester? Also, do you have an air compressor?

I think that with low compression reading from the shop, you should do your own compression test. Watch this video:


The air compressor question was for a leak down test. Another good video on how to do this test.

 

I don't own a compression tester but I'm thinking about getting one, and a leak-down tester.

I do own an air compressor.

I'll take a look at the video to get a better idea of what goes into doing a proper compression test but I'm still not buying the assessment about bad valves causing the problem.

I'm going to pour some “Marvel Mystery Oil” in the crankcase & tank and just drive her around for a while to see if anything "loosens" up.

It’s what all of us "old guys" used back in the day and believe it or not the stuff worked a whole lot more often than not.

I've looked all through this forum & many others and it seems like the carburetors on these older Honda’s were definitely a weak link, but what's amazing to me is the lack of solutions.

I see a hundred posts on the "rough idle" issues started, but no resolutions.

Thanks for the input.......

 

Update,

I threw my hands up last week and put the car in both eBay & Craigslist and then got a blessing…….

The one person that came to look at the car wanted it to restore (as this is his hobby)

Turns out the guy used to work for Honda as a certified Honda mechanic back in the eighties when my car was new, so to say that he’s extremely intimate with all of its shortcomings is an understatement.

He said the same thing my regular mechanic told me (bad valves) the carburetor is fine.

We talked forever and I learned a hell of a lot and he actually convinced me to keep the car and fix it, and now is a good time to get to the point of this update.

My plan is to pull the head and just swap it outright for a completely rebuilt, tested and warranted one. (which I found on the internet for a really good price)

I figure I might as well change the timing belt while I’m there and I’m doing research now on timing belts but I really want to choose a good one because I don’t want to rip it all apart in six months because of a cheap or defective belt.

You experts are more than welcome to chime in here and guide me to a belt manufacturer that you trust.

Thanks in advance…….

 

Sounds like a good plan; then only thing I might do different is to have your head rebuilt as it is a (semi) known quantity. IMHO, a head with a warranty that happens to have a warranty issue (like maybe a small crack that only opens when things get really hot) still means another round of labor to replace the head.

 

On my Honda's I've always used Gates timing belts, never had an issue.

If you are going that far might as well think about the belt idler. The water pump is up to you......on these it CAN BE changed without pulling the timing cover but you are going to be looking right at it