Boats For Sale:
98 SN weird idle issue |
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cragginshred 
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Joined: August-25-2011 Location: California Status: Offline Points: 385 |
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 Topic: 98 SN weird idle issuePosted: September-10-2018 at 5:46pm |
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We just replaced the distributor cap and that fixed the issue of getting out of the hole but after numerous adjustments the idle cannot stay at a consistent rate, it sounds good then idles down then comes back to normal then down again. Fuel filter was changed with good pressure under test, premium fuel in it with additive for injector cleaner.
Ideas? |
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Bri892001
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Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Posted: September-10-2018 at 6:40pm |
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Is this a GT-40 motor or a carbureted boat?
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8122pbrainard
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Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Posted: September-10-2018 at 6:55pm |
What other adjustments? |
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cragginshred
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Posted: September-10-2018 at 7:41pm |
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GT 40 Fuel injected
He was adjusting the bolt below the distributor cap. |
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cragginshred
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Posted: September-10-2018 at 7:42pm |
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To adjust the idle
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gt40KS
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Posted: September-10-2018 at 10:25pm |
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A pic of the 'bolt' could help, but I'm a bit confused..... was he adjusting the idle screw @ the throttle body or was this bolt actually "under" the cap, as in inside the distributor? .... Because I can't imagine what you'd adjust under the cap to change the idle
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JCCI
1995 Ski Nautique GT40 |
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cragginshred
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Posted: September-10-2018 at 10:44pm |
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@GT40KS it was just Below the cap not under it.
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gt40KS
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Posted: September-10-2018 at 11:14pm |
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Idle issues with the GT40 are numerous so at this point you may have to just go through the checklist. Was the distributor moved at all (timing) when the cap was replaced? What about vacuum hoses, etc.? Did the IAC get unplugged? MAP sensor? All the plug wires seated well?
If all those check out, rolling idle issues with the GT40 could include a failing IAC, failing PIP sensor (inside the distributor), failing throttle position sensor, plugged or pinched vac hose to the map sensor or bad map sensor. I believe there are a couple of other likely suspects, just can't think of them right now |
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JCCI
1995 Ski Nautique GT40 |
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cragginshred
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Posted: September-10-2018 at 11:38pm |
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He was adjusting the timing not the idle
The boat pulls great out of the hole now......but to sell it the club will want the idle corrected. |
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Gary S
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Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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Posted: September-11-2018 at 2:35am |
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Was the SPOUT connector disconnected when you/he was setting the timing ? You were using a timing light right?
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KENO
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Posted: September-11-2018 at 7:56am |
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I guess a little background would help about now
 What was the "getting out of the hole" issue? You don't seem to have any recent posts about this. Was the idle smooth before the cap was replaced? Was the fuel filter changed before or after the idle issues? |
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cragginshred
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Posted: September-11-2018 at 12:07pm |
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He did NOT use a 'timing light' -good call. I will bring that up
He called the issue 'Hunting' he thought the engine would idle down from a 'normal' idle because it was 'hunting' for the correct timing. **We had it on the water to make sure it had the correct 'giddy up' out of the hole which it did.........previously it did not and was missing. Because the fuel pressure checked out and the filter and just been changed he went to the Cap- which fixed most of the issues. Will the timing light be key to 'fine tuning'? Taking it to a real Marina shop this week. Hopeful they can get it sussed out. Thanks fellas! |
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cragginshred wrote: