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MerCruiser 43 liter wonbt idle

E

Ed Sanchez

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"I have a 1991 searay 17ft bow

"I have a 1991 searay 17ft bowrider. The boat runs great but has trouble idleing. When I start the boat in nuetral it cranks right up if I give it a little throttle.But if I come back to center to put it in gear it will die on me. This is my first boat, and this seems to be the only issue it has. I can even cruise around at trolling speeds, but once I come to a stop and bring the drive handle back to center it won;t idle very long before it dies. Is it easy to try to adjust the carburetor or should I take it in. Thanks for any input. Ed"
 
"Hi Ed,
I am no expert but I


"Hi Ed,
I am no expert but I just bought a 87' with a 3.7L carbureted and had the same issue. I finally got mine running perfect this weekend. Here is what I did.

1. Fuel filter(s) You probably have 2 one before the fuel filter one inside the carb (right where the fuel line enters the carb inside the BIG nut)
Also check the "spark arrestor" for clogs. This is the round disc looking metal cover on the carb, it is like an air filter and can clog with the "blow by". Blow this out with starting fluid and compressed air.

2. Old gas? If it was sitting for a year or so, you may want to drain the fuel and start w/ fresh fuel.
Again if sitting any length of time you will want to do a full tune up anyway to have a reliable boat

3. a.Spark plugs and wires, fouled or what ever.
b. Distributer cap, Rotor
c. Points, if you have a points system (if you have an electronic ingition you dont have to worry about this.

If you have a carb and not EFI (fuel injection)

4.Check for bad gasket under carb or intake. This can be done by spraying starter fluid right at the base gasket of the carb while at an idle, if you notice a increase in idle speed you probably have a leak.

5. You may be able to adjust your Idle speed needle, but if this was set an running at one time there is probably something else wrong with the carb. (Dirt or gummed up)Your manual will explain how to do this, basically from an idle you adjust in 1/4 turn increments wait like 20-30 sec and you watch for highest idle on your tach then fine tune to make sure it accelerates without poping thru carb.

If none of that fixes your problem you may have to rebuild your carb.
6. Mine just had "varnish" and bad gas and dirt clogging the jets and needle valve. But you need gaskets anyway, so get a rebuild kit for the carb. It will only run you,like $50 with shipping. If you are not comfortable with doing this a remanufactured carb will run from $250-$500.

That should cover most basic things to tune up a carbureted boat.

Hope that helps."
 
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