Boat doesn't want to stay running

JasonGS

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I have tuned the carb with a vacuum gauge after the motor was warm... Started today fine was running for about a minute and then just died started back up increased the idle to about 1000 rpm and it still died what am I doing wrong????
 

bruceb58

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Re: Boat doesn't want to stay running

So what do your plugs look like? You running rich? Personally, I have never needed to use a vacuum gauge to set idle mixtures. Its pretty darn straight forward.

You probably have the mixture set to rich and you are fouling your plugs.

Of course I am assuming everything else is in good working order besides the carb. Points, dwell and timing are all set properly.
 

JasonGS

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Re: Boat doesn't want to stay running

Ill check them tomorrow...
 

Don S

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Re: Boat doesn't want to stay running

What engine? Model number? Year?
 

Silvertip

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Re: Boat doesn't want to stay running

There are multitude of things that prevent an engine from idling/running properly. Some of those have been mentioned. If the choke is not working (as in stuck closed) that will kill the engine as it starts to warm up. And if that wasn't working properly, your mixture adjustments are also out of whack. Vacuum leaks, a carb that needs rebuilding, bad gas and lack of a good tune up including distributor cap, rotor, points, plugs and wires may be needed. Knob twiddling rarely cures a poor running engine.
 

Don S

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Re: Boat doesn't want to stay running

It could also be a bad alternator or blown diode.

If your engine has an electric fuel pump, OMC uses the alternator to power the relay to run the pump after starting.
 

JasonGS

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Re: Boat doesn't want to stay running

Checked spark plugs and they are jet black... Hence running rich... The carb was just rebuilt less than 3 months ago... New spark plug wires were put in and spark plugs but now need to replace them again:facepalm:...
 

bruceb58

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Re: Boat doesn't want to stay running

You don't know if its the idle circuit or not that is rich. Could also be float level. Have you run the boat at speed yet?
 

JasonGS

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Re: Boat doesn't want to stay running

Yes ran it 3 times on the water....
 

JasonGS

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Re: Boat doesn't want to stay running

1994 4.3 don't know the model number off the top of my head at work right now..
 

Don S

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Re: Boat doesn't want to stay running

When it dies, don't try to restart it. Go back, remove the flame arrestor and have someone operate the throttle linkage and see if any fuel squirts out of the accelerator pump holes in the carb.
 

JasonGS

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Re: Boat doesn't want to stay running

It does squirt out the accelerator pump holes
 

Don S

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Re: Boat doesn't want to stay running

Since it squirts fuel, does it restart easily? If not, do you have spark when it dies?
 

JasonGS

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Re: Boat doesn't want to stay running

Once the boat is warmed up it starts up fine but to get it to warm up is really difficult...
 

bruceb58

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Re: Boat doesn't want to stay running

What is the choke doing while it is warming up?
 

Silvertip

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Re: Boat doesn't want to stay running

This is a classic stuck or inoperative choke. Since you "rebuilt" the carb, there is a good chance you have the choke linkage mucked up and or the choke is incorrectly adjusted. So I'll ask again too, what's happening with the choke? On a stone cold engine the choke plate should be closed. Not tightly but a light finger pressure on the back side should cause it to open. If not, it's adjusted too tight. As the engine begins to warm up it should begin to open until it is standing fully vertical in the carb throat. If the heater wire attached and is there voltage on the wire? To fine tune the choke, let the engine cool overnight. Then loosen the adjustment so the choke opens, then begin closing it until it just closes. Done, go boating. DO NOT ADJUST THE CHOKE ON A WARM ENGINE. You will end up with the same problem you now have. If this procedure does not work, then there are other issues with the linkage.
 

talies13

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Jan 27, 2012
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Re: Boat doesn't want to stay running

I'm not an expert, but my no hot start was also a choke issue. Sounds like yours is toto ! I adjusted mine correctly and it starts every time in less than 2 seconds!
 
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