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FORUMS arrow Maintenance arrow 5.7 Mercruiser Choke Issue?
Topic Title: 5.7 Mercruiser Choke Issue?
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Created On: 05/03/2009 10:18:26 PM
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05/03/2009 10:18:26 PM
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tnlegendracer
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Posts: 44
Joined: 09/05/2005

While replacing plugs, wires, cap and rotor on my 1995 Mercruiser 5.7 with 2 barrel carb, I noticed choke was open. I thought that not normal as engine was cold. I turned on key and choke was still open. I took 12v test light and hooked clamp to positive side of battery. With key off, test light comes on when I touch both the wire on the choke plug and the wire that's on one of the choke screws. I read that to mean both of those wires are running to ground. Can the choke function like that? I can't see how.
Please advise and thanks!

-------------------------
 2000 17 x 90 Stardust
2006 Yamaha FXHO Cruiser
1997 Yamaha WVT1100
2004 Malibu 23 LSV Hammerhead
2003 21' Suntracker Pontoon 75hp Merc FS
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05/04/2009 10:58:55 AM
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FranticallyRelaxing
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Joined: 09/10/2006

Did you open the throttle? There's a cam on the throttle linkage that will prevent some choke plates from closing until the throttle is opened. Try it. If the choke doesn't snap shut, then re-check the wires. With the key off, there's no power to the hot side, and since it's just connected to a thermal spring that the other end of is connected to ground, there's probably enough resistance to make the test light come on.

OR, it could be the hot IS shorted to ground, in which case a fuse would likely be blown. Just check the hot wire to the choke with the key ON. If you have power, then no problem.

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1988 SkipperLiner 53x14
1995 Tracker Party Cruiser 32 *for sale*
2003 Chaparral 260 SSI
2000 Allegro Bus 40' DP

Edited: 05/04/2009 at 11:09:14 AM by FranticallyRelaxing
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05/04/2009 12:24:52 PM
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tnlegendracer
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Joined: 09/05/2005

Thanks Frantic. I'll try that tonight. I found it odd that the choke plate was open by default. I can move it (from other side of carb) to open or shut and it stays where I put it. I'll see if it's an adjustment issue tonight and try the throttle. Some have advised that it's activated by oil pressure or alternator being energiezed, but that wouldn't explain the default open position.

Heck, it may just be adjusted that way.

-------------------------
 2000 17 x 90 Stardust
2006 Yamaha FXHO Cruiser
1997 Yamaha WVT1100
2004 Malibu 23 LSV Hammerhead
2003 21' Suntracker Pontoon 75hp Merc FS
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05/04/2009 02:21:38 PM
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Jeepster04
Admiral

Posts: 310
Joined: 09/15/2008

Like FranticallyRelaxing said, youve got to give it some throttle to close the choke. The choke was open last time the engine ran then when you throttled down and shut the engine off, the closed throttle held the choke open. You should always give it some throttle before starting a cold engine so the choke closes.

Could be different on yours but thats how our Rochester works..

-------------------------
 1990 16x78' stardust
Eastern Ky
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FORUMS : Maintenance : 5.7 Mercruiser Choke Issue?

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