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Carb Problems?

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Smothers65

New member
I have a 1988 3.0L in board Mercruiser. I have always taken the best care of it and have never had a single issue. Recently, it sat in my garage for 2 years without being started. After I took it on the water last year, I figured the fuel was a little old in it and since it sat for a while, I put some Seafoam in the fuel tank. Since then, it starts fine cold but starts hard warm, especially when I'm on the water. It just turns over for about 5-6 seconds and I have to give it a lot of gas before it sputters to a start. It rides fine but when you accelerate (like when pulling a skii'er out of the water) it sputters right off the start. I checked for an inline fuel filter thinking it might be clogged but I couldn't find one. Could it be that the carb is gummed up and needs pulled/cleaned? If not, any other suggestions? Thanks for your help.
 
Smothers65 said:
.......... It just turns over for about 5-6 seconds and I have to give it a lot of gas before it sputters to a start. It rides fine but when you accelerate (like when pulling a skii'er out of the water) it sputters right off the start.
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I'll first suggest that it may be the accelerator pump piston.... or perhaps the check valve in this circuit.
The accelerator pump fattens up the F/A mixture during the transition between low speed metering and high speed metering.
If this is not functioning correctly, you may feel a stall or hesitation, and it may sputter or even backfire depending on the load.

Often carburetors require nothing more than cleaning and the renewal of the parts included in the kit... of which should include the pump piston and possibly this check valve ball.
 
I was planning on cleaning and putting in a new carb kit (which you said should include the accelerator pump piston/check valve) so hopefully that takes care of the problem. I will let you know as soon as I try it. Thanks Rick.
 
I checked for an inline fuel filter thinking it might be clogged but I couldn't find one.
Click to expand...

Ayuh,.... There should be a filter inside the fuel pump, 'n another inside the carb's inlet fitting....

Btw,... Adding anything to sour fuel does nothing to fix rotten fuel... Pump it, 'n dump it....
 
You can check the accelerator pump's function before tearing the carb apart. disconnect the throttle cable and pull the flame arrestor. Hold the choke plate open and look down ito the carb's throat. work the linkage. You should see two streams of fuel squirt out as the throttle opens. If they are missing, time to get the carb kit.

Like Bondo said, only way to get rid of bad fuel is to pump it out. Better to spend a day getting that striaght now than to deal with it all summer long.

As far as the hard to start hot...try opening the throttle at least half way before you try to crank it hot. running the blower for a while after you shut it down will help a lot, too. The 'new formula' they make gasoline with really doesn't like a lot of heat amongst other issues.
 
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