Rejetting for change in Altitude 95 sunsetter

[robandrus]

Just bought a 95 Sunsetter with the 5.7 Mercruiser engine, carbed boat from a guy who had it on the Delta in Cali. I brought it back to Utah and now it's extremely hard to start. Does anyone know what kind of jetting changes I need to make?

[radioman]

A jet change wont help a hard starting condition. I would check the choke if it has one or the well plugs might be leaking. A carb engine will be nature self adjust the fuel mixture from sea level to 4000 ft.

[Woodski]

As mentioned, check the choke. It actually needs to be adjusted twice a year to compensate for temperature. Check how tight the choke is and adjust accordingly.

[Sunsetter95]

A jet change wont help a hard starting condition. I would check the choke if it has one or the well plugs might be leaking. A carb engine will be nature self adjust the fuel mixture from sea level to 4000 ft.

Is it a starting hard issue, or is there not fuel to the carb let? Mine takes a little while (cranking), then fires right off.

If fuel in the carb is not the issue, do you know what kind of carb is on it, Carter or Q-Jet? The Q-Jet, as mentioned above, are known to leak from the well plugs. They can be found between the base and the center section of the carg. Most kits have them. They look like a piece of foam about 1/2" thick and kind of kidney shaped.

I would first ensure the choke is working properly, get it warm and adjust the idle mixture for best idle and vacuum, then run it. If it has a Q-Jet and you can turn one of the screws in all of the way and the engine is still running, then you may have a plug leak.

If it seems to idle pretty good after the adjustment (smooth and no black smoke), you can change out the spark plugs and take it out for another cruise at high and low speeds, then pull the spark plugs and look at their color. Clean or light to medium brown is good, if they real dark or black, then I would consider leaning out the carb jetting. This will not work if under the load of skiing or boarding, they will get dark because of the extra fuel needed for that type of operation.

I you are not familar with this carb work, I would find some one who is. Also, I would not buy a rebuilt carb unless you know for sure your carb is defective (broken) in some way, I would rebuild your original. IMO

I paid to have mine done. Since I installed it and adjusted it for idle three years ago, it has performed perfectly.