stalling / backfiring

[tjb1231]

Last year the boat ran great. I fogged the engine and ran stabil through the gas. This year I can't get the boat to idle down or start easily. If the boat starts it runs great over 1500 rpm. If I try to idle down, it stalls.
I Added 10 gal fresh gas to the existing 7 gals of gas and changed plugs. This seemed to help because I could not go below 2000 rpms before this.the fuel filters are clean. The choke is not sticking and the carb seems clean when I look down into it.

When trying to start, there is lots of backfiring through the carb.

the boat is a 1989 with the 3.0. I do have the serial numbers at home but I am at work now. I will post those later.

What troubleshooting steps can I take?

THANK YOU!

 

[bspeth]

Check the firing order?

 

[tjb1231]

I can double check but when I replace plugs I do them one at a time. I'll add that to the list of things to check.

 

[NHGuy]

Was it running badly before you changed the spark plugs? How did the old ones look?
I'd say recheck that the plugs are torqued down and the wires are down in their sockets. Also is the cap all the way on and in the right spot? Caps normally have a notch to make them sit on the distributor at the correct angle.

 

[tjb1231]

Yes it was running badly before the plugs when I tried to run it for the first time this year. Between plugs and new fuel, it did run better but still not right. This boat doesn't have a cap. The plug wires go into some gel thingy.

The plugs were a little black, but otherwise good shape. I am thinking it's the gas.

 

[nateo]

I spent the first month of last season figuring out how to properly tune up an old boat. After tune up mine ran great the rest of the season. Make sure distrubtor is properly tightened down. Set the idle / fuel mixture screws (depends on the carb but mine was two and half turns from bottom). Then set your timing. One of these often come loose over time from vibration. Once you have the knowledge this ends up being a 30 minute job.

 

[nateo]

Mine was not a gas problem. basic run of the mill tune up is probably needed.