Tri-Power Idle Drops Under Braking
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Burning Brakes
Joined: Jun 2014
Posts: 924
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From: Brentwood CA
Tri-Power Idle Drops Under Braking
After sitting for more than a month, I took the '69 out for a short drive around town yesterday and, after reaching operating temperature, the idle started to drop ~200 RPM or so while coming to a stop. It nearly died a couple of times. When completely stopped the idle would immediately recover. It was very consistent and happened at just about every stop I made. When I got home I checked the fuel bowl level of the center carb and it was where it's supposed to be. Any thoughts as to what could be causing this?
Thanks,
-Doug
Thanks,
-Doug
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
As Steve stated, it is caused by fuel slosh in the bowl. Typically, under braking, the fuel sloshes forward, away from the jets, introducing a momentary lean condition. To lessen the effect of the problem, it often helps to richen up the idle mixture screws about 1/8 to 1/4 turn.
Lars
Lars
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
That's correct - it will further aggravate the lean condition caused by the fuel moving forward in the bowl. But since he stated that the float level was checked and verified to be correct, the best he can do is to richen it up a tad so it runs just a little on the rich side at normal idle, and does not go excessively lean under braking.
Lars
Lars
