Posted by T.L. on January 18, 1999 at 17:52:00:
In Reply to: AAAAARGH! it may be my carb! posted by Sparks on January 18, 1999 at 11:09:11:
Check the firing order again and the timing as was mentioned...
Seems like whenever there's a problem the first thing people say is: "could be a vacuum leak". Well you mentioned that the plugs were black when you pulled them. This could be carbon buildup but it could also mean that the motor is running too rich. A misadjusted float in the carb and dump too much fuel into the intake and cause backfiring. Of course "surging" is usually the result of a lean condition, hence the vacuum leak theory. But if the motor was running lean, then the spark plugs would have been white when you pulled them, not black. Ultimately, it shouldn't be too difficult to troubleshoot keeping in mind that your engine needs 3 things to run: air, fuel, and spark...
: Last weekend I pulled a plug to take a look. They were all black, but looked good. The shop that installed them must have used the "out of the box" gapping method. they were all .025".
: So, I cleaned them up and reset the gap (except for the one on the passenger's side I couldn't reach- 3rd back from the front, passenger side)
: Lo and behold she ran fantastic.
: This weekend I go after the last plug, and had to put in a new one. (it was very old, and insulator broke upon removal).
: I used a can of carb cleaner on the carb (factory 2bbl)It was so black it didn't even look metal, replaced some cracked vacuum hoses, replaced the breather, air and fuel filters.
: It resisted starting, and had some backfiring. So I replaced the wires. I did'nt have the buckos for the good ones right now, so I bought
: what the shop had. This made a litte difference, but not much.
: The most noticable problem is upon acceleration between 25 and 45MPH. It surges and backfires.
: I cannot swing the price of a carb right now, or even the price of shop help.
: This Mav is used daily - I got it to keep me out of the elements. (normally ride a Mcycle)
: I should be getting a Chilton Manual this week- I was high bidder at ebay.
: In the meantime, I could use a litte advice.
: one more thing, on the side of the carb is a round black device my mechanic referred to as a preheater
: when I had the water pump replaced. It is set as rich as it will go. I tried moving it from as lean as it will go and back, and different points in between,
: with no difference in performance.