F'ing thing won't idle
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F'ing thing won't idle

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    Or Seth, either one Budweiser's Avatar
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    Default F'ing thing won't idle

    When I first put it in the water I step on the gas a couple times and she fires right up and happily idles as low as 600rpm (wont hold that setting in gear though), but I usually set it about 900-1000 which put the idle at 700 in gear. When I'm cruising or wot for a while and come back down to idle, it stalls and wont idle at all. Not sure if it's a temperature issue or not. Also, on long cruises at night the headers glow bright orange, even at part throttle.

    I don't want to steer your responses too much, but I'm thinking it's just way too rich or timing is retarded (slipped outer ring on the balancer)

    18' v-drive, 396 BBC, +/- 10:1 cr, performer intake, Edelbrock carb (1407) w/mechanical choke, 2" "open" carb spacer, vacuum advance HEI distributer (hooked up to manifold vacuum) timing is set at 36*, plugs gapped at 0.040, 160* thermostat, 049 heads, unknown mechanical cam.

    OH! one other thing I notice that the first time I go WOT rpm's go up to about 4700 rpm, but as I stay on it it goes down to about 4300, usually within a few minutes.

    So, where do you think I should start? What's your take?
    Last edited by Budweiser; 03-13-2009 at 12:43 PM.

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    I would first check for a vacuum leak around the carb or spacer. exhaust gas temp should be about 1250deg on gas. at wot. IMO. That is not hot enough to turn the headers red. I have had trouble getting those carbs to make power over 5000rpm. But it sounds to me like it's going lean and then noses over. Check that, then put a new set of plugs in it and make a short run at wot. About a half mile or so. the plugs should have a brownish color to them. and all look about the same. If all else fails check fuel psi 7lbs wot, if that's ok then swap carbs. Hope this helps.
    J

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    Quote Originally Posted by Budweiser View Post
    When I first put it in the water I step on the gas a couple times and she fires right up and happily idles as low as 600rpm (wont hold that setting in gear though), but I usually set it about 900-1000 which put the idle at 700 in gear. When I'm cruising or wot for a while and come back down to idle, it stalls and wont idle at all. Not sure if it's a temperature issue or not. Also, on long cruises at night the headers glow bright orange, even at part throttle.

    I don't want to steer your responses too much, but I'm thinking it's just way too rich or timing is retarded (slipped outer ring on the balancer)

    18' v-drive, 396 BBC, +/- 10:1 cr, performer intake, Edelbrock carb (1407) w/mechanical choke, 2" "open" carb spacer, vacuum advance HEI distributer (hooked up to manifold vacuum) timing is set at 36*, plugs gapped at 0.040, 160* thermostat, 049 heads, unknown mechanical cam.

    OH! one other thing I notice that the first time I go WOT rpm's go up to about 4700 rpm, but as I stay on it it goes down to about 4300, usually within a few minutes.

    So, where do you think I should start? What's your take?
    timing is set to 36, then you gave it manifold vaccum???? if ya did, that's your issue. hope ya didn't melt any pistons. base timing for a hei otta be around 8 degrees btdc, the mechanical advance part will carry it into the 20's, then the vaccum advance will carry it on up from there. headers glowing is a sure sign of a lean issue, wether that's a fuel issue or ignition.i'd wanna see what max advance actually was while the motor is working hard.

    ditch the vaccum hose to the intake , use the mechanical advance built into most hei dizzys instead. give it max 36, no more.

    Dare to be different, if it turns out great you can claim you planned it that way.

    Jetboatperformance.com

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    Or Seth, either one Budweiser's Avatar
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    Quote Originally Posted by IMPATIENT 1 View Post
    timing is set to 36, then you gave it manifold vaccum???? if ya did, that's your issue. hope ya didn't melt any pistons. base timing for a hei otta be around 8 degrees btdc, the mechanical advance part will carry it into the 20's, then the vaccum advance will carry it on up from there. headers glowing is a sure sign of a lean issue, wether that's a fuel issue or ignition.i'd wanna see what max advance actually was while the motor is working hard.

    ditch the vaccum hose to the intake , use the mechanical advance built into most hei dizzys instead. give it max 36, no more.
    Clarification: I set timing at 36* at 5000rpm with the vac advance disconnected.

    And... the headers glow all the way from the flange to the collector. You don't see it during daylight though, only at night. And you can see blue flames out the end Doesn't make sense that it would be lean, but if that's the concenses...

    OH! the plugs look clean, porcelain is white. They have about 4 days run time on them and they're still pretty darn white.
    Last edited by Budweiser; 03-13-2009 at 01:51 PM.

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    Good point, I missed that intake vacuum part. a $4.99 timing tape is never a bad idea.

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    Quote Originally Posted by Budweiser View Post
    Clarification: I set timing at 36* at 5000rpm with the vac advance disconnected.

    And... the headers glow all the way from the flange to the collector. You don't see it durring daylight though, only at night.
    yep, your giving it wayyyyyy too much timing advance. run it without the hose!!! plug em up and never think about a vaccum advance on a boat again!

    change those plugs too while you at it, they've been detonated and you don't want that insulator in the cylinder!!

    Dare to be different, if it turns out great you can claim you planned it that way.

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    So is the advance hose off or on?

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    Quote Originally Posted by shooter1 View Post
    Good point, I missed that intake vacuum part. a $4.99 timing tape is never a bad idea.
    timing tapes are great as long as they're installed when the motor was tdc'd, otherwise you'd be trusting that the balancer/timing tab are correct and that's rarely the case, at least i've never seen it perfect before. i've actually had to pull off the head to tdc a friends boat that i knew wasn't right, his marks were off 13degrees

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    Quote Originally Posted by shooter1 View Post
    So is the advance hose off or on?
    glowing headers answer that for ya, it was on

    set the timing at 36 max, if you have 4 corner idle on the carb, screw them all in and back em out 1 1/2 turn just as a base tune-up. that should get ya close on idle mixture, enough to play with it without the motor loading up and die'n or leaning out.

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    Or Seth, either one Budweiser's Avatar
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    Quote Originally Posted by shooter1 View Post
    Good point, I missed that intake vacuum part. a $4.99 timing tape is never a bad idea.
    Have the tape on there, it is the only way to go without dropping coin on a fancy dampner or dial back timing light

    Quote Originally Posted by IMPATIENT 1 View Post
    yep, your giving it wayyyyyy too much timing advance. run it without the hose!!! plug em up and never think about a vaccum advance on a boat again!

    change those plugs too while you at it, they've been detonated and you don't want that insulator in the cylinder!!
    Sorry, I think I was editing my post above to add a few details when you posted this...

    Anyway, it's not detonating. I don't want to get in to the whole vac advance discussion again, but at WOT there is not vacuum and therefor no advance other than centrifugal advance, and the extra advance at idle is "supposed" to give a better idle.

    I really don't think it's too advanced or too lean, with flames out the tail pipe... I've been wrong many times before though.

    Either way, I'm not understanding how either of those would affect the idle the way what ever it is does.

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    when i drop in a fresh motor, the 1st thing i worry about is setting the timing right(after oil pressure is checked of course), from that i move to idle mixture. you can advance timing and make the idle move up, you can retard timing and it'll drop rpms.

    say you're timing is high and you carb is lean at on the idle circuits, well your idle with the pump loaded will be shit.

    fyi, unless you have a perfectly working motor, your advance port on your carb will still have vaccum on it at wot. i could be wrong but a vaccum gauge and a heavy foot would clear that up for ya check it just for shits and giggles man.
    Last edited by IMPATIENT 1; 03-13-2009 at 02:23 PM.

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    Quote Originally Posted by Budweiser View Post
    Clarification: I set timing at 36* at 5000rpm with the vac advance disconnected.

    And... the headers glow all the way from the flange to the collector. You don't see it during daylight though, only at night. And you can see blue flames out the end Doesn't make sense that it would be lean, but if that's the concenses...

    OH! the plugs look clean, porcelain is white. They have about 4 days run time on them and they're still pretty darn white.
    If the plugs are still that clean , sounds like your real lean . Unhook the hose to the advance and set total timing at 36degrees and then see what it is at idle you may have to much mechanical advance in that dizzy. Then check into the lean condition, back the idle mixture screws out a half turn and jet that baby up a few jet sizes and see what the plugs look like after a 1/2 mile run.

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    If it was rich, you would be trailing black smoke. The plugs would be black.
    If you have 36*at wot. White plugs after four days of running. RPMs that run up to 4700 then fall off to 4300. and headers turning red. Poor idle. I keep going to a vacuum leak.

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    Quote Originally Posted by shooter1 View Post
    If it was rich, you would be trailing black smoke. The plugs would be black.
    If you have 36*at wot. White plugs after four days of running. RPMs that run up to 4700 then fall off to 4300. and headers turning red. Poor idle. I keep going to a vacuum leak.
    its possible, but he's feeding it too much advance if its the basic ole hei dizzy. i've seen them vaccum advance at wot with my own eyes watching the lite and timing marks. my dominator 1050hp on a big compression motor at 6800rpms would still show some vaccuum under the carb. as blower motor will also see vaccum under the carb if the carbs are a bit too small.

    Dare to be different, if it turns out great you can claim you planned it that way.

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