stalls while trying to idle in gear

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EDouthit

Recruit
Joined
Apr 15, 2011
Messages
3
I have a 70 model mercury 800. It stalls out when trying to idle around at low rpms(around dock and what not). Im not a boat mech. by no means but I am fairly mechanically inclined. Is there any adjustment that can be made to fix this problem? It runs fine at full throttle but stalls and dies at low speeds. Low enough for no wake, and seems to be worse when the motor is warm. Any advice would be greatly appreciated. I haven't got a manual yet so if pics are possible that would be awesome. Thnx.
 
jerryjerry05

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,196
Re: stalls while trying to idle in gear

Profile? Try to set up the idle. Ethanol is messing with the fuel system.Check the hoses and carbs.Replace all old ones,squeezie too.Rebuild fuel pump.Clean the carbs.Do a compression test.J
 
C

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: stalls while trying to idle in gear

Most likely the idle mixture is off, maybe due to mineral accumulation of fuel.

Follow jerry's advise, clean carb, rebuild fuel pump, replace all aging fuel hoses, primer bulb.
 
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EDouthit

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Apr 15, 2011
Messages
3
Re: stalls while trying to idle in gear

Thnx for the quick come back. I'll try those suggestions. Have a great day.
 
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bucknall911

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Joined
Apr 16, 2011
Messages
2
Re: stalls while trying to idle in gear

guys, I'm experiencing similar problems. 700 merc cruiser, runs like a champ in the driveway. Over hauled with new carbs etc. but when placed in the water, any drag on the motor at all and it stalls and sometimes refuses to start without a blast of extra juice in the carbs. So runs like a beast sitting on the pavement, but dies when throttled. any help. I'm a girl messenger
 
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Maxz695

Guest
Re: stalls while trying to idle in gear

sounds like fuel starvation check the bulb pump thinggy all fuel filters hosses for cracks letting in air. and then the fuel pump
 
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bucknall911

Recruit
Joined
Apr 16, 2011
Messages
2
Re: stalls while trying to idle in gear

Completely replaced all fuel lines, tank, wiring redone by a man...lol. ONly thing not checked was filter and pump. Everything has been replaced, repaired and stumped. Getting frustrated that I have a land shark.
 
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Maxz695

Guest
Re: stalls while trying to idle in gear

disconnect the line from the carb carbs turn the engine over and see if you get fuel if not rebuld the fuel pump after you change the filter . it would be a shame to do all that work over a 5 dollar filter. Also keep in mind even with a semi clogged filter you will get fuel coming through which most likely because you do run and this may be the issue. My siter learned alot from me back in the days she just could not help sticking her hands in there and getting dirty. Thats what makes a great machaninc DIVE IN Head first come out smiling but dirty. good luck hope I helped
 
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Moody Blue

Captain
Joined
May 24, 2004
Messages
3,136
Re: stalls while trying to idle in gear

EDouthit said:
I have a 70 model mercury 800. It stalls out when trying to idle around at low rpms(around dock and what not). Im not a boat mech. by no means but I am fairly mechanically inclined. Is there any adjustment that can be made to fix this problem? It runs fine at full throttle but stalls and dies at low speeds. Low enough for no wake, and seems to be worse when the motor is warm. Any advice would be greatly appreciated. I haven't got a manual yet so if pics are possible that would be awesome. Thnx.
Click to expand...

I've got the same motor and had experienced exactly the same symptoms you describe. I found that this motor was VERY finicky about ignition timing / carb synchronization and idle mixture setting. Read through this post http://forums.iboats.com/showthread.php?t=168855 for a great write-up on the link & sync proceedure. I had to repeat the proceedure several times before I got it dialed in. If the carbs have not been rebuilt, that would be a good starting point, because even if all else is setup properly but the idle circuits in the carbs are gummed up, it will not idle well.
 
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