H.A.C questions

660canuck

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When a H.A.C system stops working what are the symptoms? I have a 1994 Summit 583 that is bogging something fierce. I cleaned the carbs and rave valves, but it is still bogging. It will start, but when you try to give it gas it is super slow to rev up, or bogs and dies, or backfires and dies. Seems to me that it is running extremely rich and I suspect the H.A.C to be the culprit.
 

Modman

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The HAC was designed to revert to full rich mode if it failed. Clean the carbs first, then if its still not running right, take the HAC lines off, and re-jet a couple sizes down, if it runs better then it is the HAC and you will have to start with the non-HAC sled specs for jetting and work your way down from there.
 

660canuck

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Thanks, do you just plug where the hac lines went into the carbs?
 

Modman

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Thanks, do you just plug where the hac lines went into the carbs?

yes, put some shrink wrap over them and heat it, once it shrinks then pinch the end together and it will give you a nice good seal that won't leak.
 

Modman

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Don't the vent lines on the carbs still have to be open?:d

Yes you are correct, sorry.

Depends if the float bowls are vented separately or not (can't honestly remember on those ones), on the standard carbs they are vented on each side so you can just plug the one side but the HAC ones are not I don't think, its just on the one side back to the HAC. Plug the HAC lines using the method above but add a small hose to the float vents so they are vented to atmosphere.

Thanks Renegade, good observation.
 

660canuck

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Thanks guys, I removed the H.A.C, rejet using the specs for the Formula 583, and she is running great.
 

TheBearAk

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Thanks guys, I removed the H.A.C, rejet using the specs for the Formula 583, and she is running great.

Can I ask what those specs are?

I'm having trouble finding the info on what size jets to use.

I also have a 1994 summit that I believe the HAC is messing up on. I rarely go to the mountains anymore so I figured I'd just remove the HAC and jet it for low altitude.
 

TheBearAk

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I don't go up in the mountains very often anymore and I'm pretty sure the HAC is acting up. It is 15-16 years old too.

I think I've figured it out, with the help of my brother.

Machine is a 1995 Summit 583 (well, MFG date is June 1994, so I'm not sure if it is a 94 or 95)

Pilots: 40
Mains: M330 and P320
 

Broz

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I don't go up in the mountains very often anymore and I'm pretty sure the HAC is acting up. It is 15-16 years old too.

I think I've figured it out, with the help of my brother.

Machine is a 1995 Summit 583 (well, MFG date is June 1994, so I'm not sure if it is a 94 or 95)

Pilots: 40
Mains: M330 and P320


Yeah, ours is a 1996 and the vacuum pod had simply lost its air behind the diaphram. We had a spare pod and it needed calibrated too. Suprisingly, they both have held calibration now and it has bee a month or longer. I tried this because it was easy and I didnt have to gather up parts to do it. I noticed the HAC's run oversized jets and to convert the carbs correctly you will probably want to change the needles too.

Once you are on to what you are doing with the re-calibration it only takes a few minutes to do. We will recalibrate every year to keep her in tune if necessary. Just thought I would toss it out there since it worked so well for us and cost us nothing.

Jeff
 

660canuck

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Can I ask what those specs are?

I'm having trouble finding the info on what size jets to use.

I also have a 1994 summit that I believe the HAC is messing up on. I rarely go to the mountains anymore so I figured I'd just remove the HAC and jet it for low altitude.

I have 40 pilots, and 350 mains in there right now, seems alright at 3500ft
 

TheBearAk

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Jeff, thanks for your reply and I do take it as good advise.

660canuck: Thanks for the specs. Isn't it recommended to run two different sizes, PTO and MAG sides? 350/340? Everything I'm reading looks like 330/320 for sealevel, which would be leaner than what you have, wouldn't it?
 
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