76 1150 starts the stalls, need help

jdog921

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May 12, 2011
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4
hello i have a 76 mercury 1150 tower of power, didnt run when i bought it, i rebuilt all 3 carbs, the fuel pump, and new plugs. got new fuel, mix it 40:1 afterwards finding out needs to b 50:1 but im sure thats not the problem. anysways, it will only start when the fast idle lever is full, starts revs up and dies. i have idle screws adjusted 1 1/2 turns out, also fuel drips from front of top and middle carbs and squirts out the bolt with hole in middle where fuel line and vent hose attach. any ideas?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,127
Re: 76 1150 starts the stalls, need help

Sure, the top and mid carbs are flooding. You need to check the float height and float drop on those two. Are the floats good? The foam ones (original) will disolve in today's gasoline w/ alcohol. The newer ones (hard plastic) can crack. Replace all that are suspect. Are the little springs on top of the floats in good shape?

Check the primary timing pickup. Put a timing light on the top plug. Set the throttle to the spot where the carbs just start to open. The timing should be 4-6* BTDC. If not, you need to do a link and synch.
 

bktheking

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Joined
Jul 29, 2008
Messages
5,057
Re: 76 1150 starts the stalls, need help

hello i have a 76 mercury 1150 tower of power, didnt run when i bought it, i rebuilt all 3 carbs, the fuel pump, and new plugs. got new fuel, mix it 40:1 afterwards finding out needs to b 50:1 but im sure thats not the problem. anysways, it will only start when the fast idle lever is full, starts revs up and dies. i have idle screws adjusted 1 1/2 turns out, also fuel drips from front of top and middle carbs and squirts out the bolt with hole in middle where fuel line and vent hose attach. any ideas?

If you have fuel coming out that vent hole the float isn't adjusted properly, know that one for a fact. The instructions come with the sierra kits, by rebuilt i'm assuming you "rebuilt" them with a kit.

Luckily for you Merc used carbs that you dont have to pull them off again, just undo the tower through bolt and the 2 float cover bolts and readjust the 2 float levers.
 

jdog921

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May 12, 2011
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Re: 76 1150 starts the stalls, need help

ya i rebuilt them and replaced all 3 floats, not sure how to adjust float, ill read seloc book, mine the float just rides on a pin looking thing., well ill try that b4 i mess with timing, i set the timing to the mark on the flywheel i think it said 21 b4 tdc had a mark for it but i guess maybe that could be off for some goofy reason, thanks and ill keep u guys updated..
 

bktheking

Vice Admiral
Joined
Jul 29, 2008
Messages
5,057
Re: 76 1150 starts the stalls, need help

the pin is the needle. I noticed when I rebuilt mine that the seat was a tad longer than the one that was in it, I had to bend the levers to get it set, there is a specific measurement on those carbs.
 

Gomer50

Chief Petty Officer
Joined
Sep 5, 2009
Messages
507
Re: 76 1150 starts the stalls, need help

I watched your video and noticed I didnt see any water coming from the tell tale hole.I hope your not running this motor without water (that will be a sure distruction of your waterpump impellar).Her is a diagram for adjusting float and inlet needle.
Carb Adjust..jpg
 

jdog921

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Joined
May 12, 2011
Messages
4
Re: 76 1150 starts the stalls, need help

no i had muffs on it, it takes a while for it to fill the block, but it does come out the hole., thanks for the concern and for the info, u 2 bob
 
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