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A few weeks ago, I was complaining about poor fuel economy. It's been steadily dropping off from its usual 11 - 13 mpg to now, 8 - 11 mpg. Here are the things that I know I've done to the engine recently and want to pick all of your brains to think of anything else it could be.
-I've been playing with the timing. I've found a sweet spot that the rig seems to like at 16 btdc. A little too advanced perhaps but I'm not ready to chalk this up to the reason for bad economy. I can see if the timing is too retarded but this is certainly not the case.
-I've been playing with the vac advance. It's currently set so that it begins to activate at around 6hg.
-I replaced the power valve. Mostly because I fried the old one when I pulled the dizzy to clean it. Rotated it 180* out upon reinstall. Oops.
- Now IMHO, this is the most significant change I made. I dropped the accelerator pump arm to the lowest hole to get rid of annoying tip in lag that I had. It cleared the problem up but I have a sneaky suspicion that this might be the culprit since I started noticing a decrease in economy right afterward. Only... how? Doesn't the accel pump just ensure that you've got an instant burst of fuel to shoot into the carb when you need it? Unless the check valve is leaking inside, I'm not sure how this might lead to poor economy.
-I've made adjustments to base idle and curb idle. 800 rpm and 600 rpm respectively.
-Yesterday, I adjusted my choke since I knew that wasn't working that well.
- I have noticed that there's a little bit of fuel seepage on either side of the carb where the accelerator shaft bushings are.
-Adjusted my idle mix. 2 1/4 turns out on each. Oh and if I turn them in first, the engine wants to die which tells me that the idle circuit is working the
way it should.
- I do need a front end alignment.
- Tires are inflated to spec.
I've now been through 3 tanks of fuel since I first complained so I'm now satisfied that I have a problem.
Any ideas???
-I've been playing with the timing. I've found a sweet spot that the rig seems to like at 16 btdc. A little too advanced perhaps but I'm not ready to chalk this up to the reason for bad economy. I can see if the timing is too retarded but this is certainly not the case.
-I've been playing with the vac advance. It's currently set so that it begins to activate at around 6hg.
-I replaced the power valve. Mostly because I fried the old one when I pulled the dizzy to clean it. Rotated it 180* out upon reinstall. Oops.
- Now IMHO, this is the most significant change I made. I dropped the accelerator pump arm to the lowest hole to get rid of annoying tip in lag that I had. It cleared the problem up but I have a sneaky suspicion that this might be the culprit since I started noticing a decrease in economy right afterward. Only... how? Doesn't the accel pump just ensure that you've got an instant burst of fuel to shoot into the carb when you need it? Unless the check valve is leaking inside, I'm not sure how this might lead to poor economy.
-I've made adjustments to base idle and curb idle. 800 rpm and 600 rpm respectively.
-Yesterday, I adjusted my choke since I knew that wasn't working that well.
- I have noticed that there's a little bit of fuel seepage on either side of the carb where the accelerator shaft bushings are.
-Adjusted my idle mix. 2 1/4 turns out on each. Oh and if I turn them in first, the engine wants to die which tells me that the idle circuit is working the
way it should.
- I do need a front end alignment.
- Tires are inflated to spec.
I've now been through 3 tanks of fuel since I first complained so I'm now satisfied that I have a problem.
Any ideas???
.
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