I have a 96 spotsman 500 im working on, it seems to hate me. ive replaced everything from the air cleaner to the plug, even the carb. still it pops in h/l/and r. what would the next logical step be. dealer isn't any help. book doesn't say anything in troubleshooting section. it runs in neutral fine but will not run well at about 1/4 throttle while in gear. thanks.