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daveb

720 trouble

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daveb
Hi all I know this has been talked about before. I have replaced plugs, wires, air cleaner, and adjusted idle mixture screw. But it still loads up under a load, if sitting still it will rev up the whole way with no black smoke if moving and give it gas it will start running rough and black smoke. any help would be greatly appreciated thanks Dave

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dan762
Hey Dave My 720 did the same thing, it wasn't in TIME. After I adjusted the timing,(which isn't as hard as it sounds) it runs fine. Good luck Danny

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blackfarms1
Dave, I am sure the others who know a lot more than I will chime in soon. It could be a little out of time, did it start this all at once or gradually? Before I went to the trouble to time it I would lean the main jet out a little at a time. I had a 9020 do this same thing and I replaced a lot of parts as you have to no avail. Leaned her out a little..ran like new. Sean

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daveb
Thanks for all the input. What is the best way to get into the main jet? This started all at once this past winter, put new air cleaner in it. Will have to check the timing. Thanks again this group is the greatest with info and the willingness to help. Dave

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mjg6319
Here's my 2 cents: I just had similar problem with my 720, it would suddenly start belching black smoke under load, turn it off start it back up and it would be fine for a few more passes then start again. I attributed it to the float sticking open on the carb, there was fuel weeping out then top of the fuel bowl. Just rebuilt the carb and it runs like new.

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daveb
hi everyone just a note rebuilt the carb tonight and the 720 runs great no more black smoke. thanks again for all the input, this site is GREAT. dave

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