Backfire???

[cartboy]

I have an old cart we use as a dock cart, an '86 I believe. We do what we can to keep it going.

Recently it had a bout of accelerator cable/fuel pump/??? problems and our local used cart dealer got it going again.

Now it backfires on deceleration, when it's engine breaking. My dog has always ridden with me but now when we head for it she won't go near it.

Any thoughts?

[GoTeeMan]

From member "ezgomike": there should be a spring between the throttle lever and the cable stop, this spring should be slightly compressed when your foot is off the throttle so that the throttle is completly closed. Any air getting into the engine through the carb will cause a backfire. Loosen the cable stop, compress the spring (slightly, you will need to play with it), tighten the cable stop and go for a cruise to see if the backfiring has stopped. If not, keep adjusting till it does, it worked for both of my old carts.

[sccowboy]

adjust the throttle plate stop screw on the side of the carb til the plate closes completely.

[cartboy]

OK & OK.

Thanks.

Next time I have time to play with it, I will.

If it makes any difference, since I got it back from my local guy, when I am not really into the accelerator it feels like it is not firing on every beat . . . like it is sputtering. Then it kinda coughs and backfires when I let off the accelerator and coast, like down the bank to the dock.

It sounds bad, but it is running so much better than before I took it in that we have endured this little nuisance.

[GoTeeMan]

I didn't have my spring compressed at all and I couldn't run at low speeds because I thought it was surging, turns out when I was barely touching the pedal trying to run at low speed I was actually turning the engine off and back on because I was at the very beginning of the pedal travel and that is where you make contact with the micro switch that turns everything on. I adjusted the spring and voila I can now run at low speed, no backfiring, runs like a champ.

[cartboy]

Thanks again.

Today woulda been my day to tinker, but after golf league I had to deal with a neighbor problem, or problem neighbor, one or the other.

[cartboy]

Neither of the above . . . the spring and stop screw are working just fine.

But y'all told me where to be looking, so Thanks!!!!

Turns out that when the local repair guy put things back together, he did not get the flexible black rubber air supply tube clamped properly. He did not get the clamp around all of it, so it was crimped, and it had slid to where it was interfering with the operation of the throttle. It was stopping the plate from closing all the way.

Now that I think about it, the day I picked the cart up it would not run properly, so I took it back. The problem was the same that day. He fixed it, but did not fix it fix it.

I fixed it again, went for a test drive, and had no backfires.

But I doubt if my dog will ride with me for awhile.

[cartboy]

I had a couple of backfires so I took another look. What was being interfered with and that I fixed is the choke.

Looking at the accelerator cable, the spring appears to be working fine and it appears to be closing all the way when the accelerator pedal is not depressed.

It is not touching the stop set, but it won't go any further.

So, the spring and the set screw appear to not be the problem.

[GoTeeMan]

So the spring between the throttle lever and the cable stop is compressed when there is no pedal pressure, correct? I just want to make sure I was reading that correctly. If so I am at a loss.

Good luck.

[cartboy]

It appears to me that way, that the spring is working fine, that the plate is closing fully, and that the reason it is not touching the stop set screw is because the screw is backed off.

I don't know if it makes any difference, but what started our recent problems is that the throttle cable broke at the stop set screw. I replaced it with all new, but the cart would only run at very low speed.

Our local guy spent a couple days trying to figure it out and finally diagnosed it as a fule pump, a problem we did not seem to have before the throttle broke.

Now we have what we have, running pretty good but backfiring when engine braking.