2001 Mercury 30 hp wont start or idle

novaboat

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So we have a 30 HP carb that just doesn't like to start. The only way I can get it to start is to flip the throttle open manually while I have someone turn it over. At that point it will only run as long as I keep on the throttle or run it in gear needs throttle to stay running. I will mention I put three brand new carbs from mercury on it and have tried the lync and sync procedure.
 

Yesterday

Petty Officer 1st Class
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Feb 21, 2012
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Re: 2001 Mercury 30 hp wont start or idle

Sounds like it's in a constant state of flooding. Carb bowl inlet valves bypassing? It did the exact same thing with 3 new carbs?
 

novaboat

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Re: 2001 Mercury 30 hp wont start or idle

Yes. Did the exact same thing with the new carbs on it. Fuel pump maybe?
 

Yesterday

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Re: 2001 Mercury 30 hp wont start or idle

Hmm no the pressure from the pump should be negated by those inlet valves when bowls are full. what sorts of adjustments are available on your carbs?
 

carholme

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Re: 2001 Mercury 30 hp wont start or idle

Is the bulb firming up when you squeeze it?

If you want to test the fuel pump, get it started and without moving the throttle, have someone ready to start squeezing the bulb as soon as it starts and keep squeezing it to see if it will stabilize and keep running. If it does, stop the squeezing and see if it stops. If that happens, you more than likely have a pump problem.

However it depends on what type of pump you have and what model engine. Do you have the engine s/n?

Gerry
 

Yesterday

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Re: 2001 Mercury 30 hp wont start or idle

Are you thinking it may be starving for fuel Gerry?
 

carholme

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Re: 2001 Mercury 30 hp wont start or idle

With limited information about the problem, always check the easy stuff first. Three new carbs are expensive, very expensive. He doesn't say whether he is running it in a bucket or on the water, whether or not he is using the enricher. Need to have the s/n to see what model he has.

Gerry
 

novaboat

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Re: 2001 Mercury 30 hp wont start or idle

The S/N is 0t288255, late yesterday we installed temporary clear lines to see the fuel was moving or if any air was getting in. It appeared to pump ok no signs of air but as fuel was exiting the pump it looked like it wanted to suck back abit. Also when the engine shut off the fuel would run back into the pump leaving that line completely empty. The primer bulb does firm up when squeezed but it doesnt seem to help much if I keep squeezing it while the motor runs, only thing that keeps it running is a higher rev. Last night when we started it I had to pull the throttle open 3/4 or so just to get it to start. Very Frustrating!

The only adjustment on those carbs are the idle set on the bottom, the the middle and top have an adjustment to sync them.
 

carholme

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Re: 2001 Mercury 30 hp wont start or idle

That s/n comes up as:

MERCURY - ( 30 H.P. (2001 ))
Serial No: 0T288255 Model No: 1F30412YD

Parts and Service Bulletins list for s/n 0T288255:

Search Results - Crowley Marine

Service Manual for your engine is p/n 90-857046R1 and I can send you a copy if you PM me with an email address.

The check valves in the fuel pump open to allow fuel from the tank to reach the carb bowls when squeezing the bulb and when you stop squeezing that primer charge should remain available at the carb bowls. That line should not drain back when you stop squeezing or the engine shuts off.

Gerry
 
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