97 yamaha g16

[Ruhigh2]

Help.....first timer .....I got a 97 yamaha g16 runs fine at slower speeds as soon as you step on the gas it backfires and dies new fuel pump filter and carb new coil .....what's going on

[cgtech]

Real OEM carb from Yamaha, JN6-14101-01-00 $233
Cheap china garbage (that usually doesn't work right) $30

Im guessing what you paid for your carb..

[Ruhigh2]

Yes it was the ebay carb but its doing the same with this carb as the old one

[CP241]

Did you actually try to diagnose and see if it was a fuel or spark issue? Or just buy some parts on ebay/amazon and hope they work?

Clean the original OEM carb you removed with carb cleaner and compressed air. Put the original fuel pump and coil back on and put all the new parts in a box. Try and run it and see what happens. If you need to replace something (you probably wont) we can help determine what needs to be replaced. And it's worth spending the cash for an OEM part not Chinese aftermarket junk.

[slonomo]

Back fire under throttle means lean fuel condition. I'm guessing the orig carb was plugged. New cheap carbs are sometimes plugged from the factory with dust, dirt, styrofoam, spiders, you name it. One piece of dirt can plug a jet and cause the lean condition.

I agree, clean the orig carb first. I usually disassemble and soak in hot water with degreaser like simple green. Soak parts for an hour, then lay out on a white towel and scrub with a tooth brush. You'll be amazed at how much nasty stuff will come off. At the very end, use your carb spray. Spray all the jets both directions, and spray off all the other parts really well. Air dry. Reassemble and test.

Also, did you by chance try to run the cart without the air filter, or with an aftermarket high flow filter? This will cause a lean condition as well. Always run with the stock intake and air filter setup.

[Ruhigh2]

I've tried all the above I replaced all parts one at a time tried same result I should add it backfires through the carb and put in new spark plug checked later very black like it's running rich

[CP241]

aftermarket carbs typically run *very* rich. To the point that the cart bogs and barely runs at all. Do a search here, you will see that 99% of people that buy the chinese carbs end up with more problems than they started with. Cleaning the OEM carb (or installing an OEM carb in the event the cart came with a chinese carb) remedies the issues. one in a hundred will install the cheap carb with no problems, but this is not the norm.

These carts are super temperamental with the air/fuel mix. Something as simple as the air box lid not being clamped tight and completely sealed will make them run absolutely terribly.

You still haven't answered if you did any diagnosis or just replaced parts. Do you have spark? is it fat and blue or weak and yellow? IS it regular and consistent or sporadic? Have you adjusted the valves? What kind of compression do you have?


There's a lot more to making something run than just swapping some parts and hoping for a magic fix... That's a very, very expensive way to fix an engine.

[Ruhigh2]

Spark is not blue more on the weak yellow have adjusted valves intake .004 and oo6 exhaust cleaned old carb several times with air and carb cleaner just bout the other to see if there was a differance checked air box for leeks made sure it was properly sealed ....the only thing I haven't tried is putting an in line spark tester to see if the plug is losing fire will check compression and post results

[Ruhigh2]

It does not lose spark and it has 130 psi compression

[CP241]

Ok yellow spark is an issue. What plug are you running?

130psi is definitely on the low side as well. Should be 160-175 range. Did you hold the throttle open when testing it?