'77 Mercury 1150 Thunderbolt Carburetor issues

[djstock1]

I just bought this boat and motor and have run it 5 times on the lake all seemed well but difficult to start sometimes. Last time out I flooded it badly and ran the battery to low to get any more cranking time. I noticed when I removed the cowling that gas was squirting out of the top carb like a squirt gun, from a little brass fitting with a hole in it, when it would turn over. Is that cylinder like shape the to the side and below it the bowl? Then if there is a problem with the float in the bowl sticking down the bowl would overflow and cause this.
How do I fix and then sync this carb back to the others? Do i need a full rebuild kit or just the gaskets or just a float?

Thanks guys

 

[Chris1956]

Re: '77 Mercury 1150 Thunderbolt Carburetor issues

That brass jet is the backdraft jet. Since fuel is exiting, the carb is obviously flooding. The float may be bad, or sticking or the inlet needle may be bad, or the carb may be dirty.

Tie to open the carb cover and see what is happening. Inspect the float for cracks or desintigration. Clean carb, replace gaskets, inlet needle and seat and float as is necessary. Set idle mix screw to 1-1/2 turns from lightly seated. Adjust for smooth acceleration and resonable idle quality.

 

[djstock1]

Re: '77 Mercury 1150 Thunderbolt Carburetor issues

That brass jet is the backdraft jet. Since fuel is exiting, the carb is obviously flooding. The float may be bad, or sticking or the inlet needle may be bad, or the carb may be dirty.

Tie to open the carb cover and see what is happening. Inspect the float for cracks or desintigration. Clean carb, replace gaskets, inlet needle and seat and float as is necessary. Set idle mix screw to 1-1/2 turns from lightly seated. Adjust for smooth acceleration and resonable idle quality.

did that and she is good to go again. I did notice some contamination in the bowl.

Thanks.

 

[mr 88]

Re: '77 Mercury 1150 Thunderbolt Carburetor issues

You may want to run some Sea Foam through it. I would even put some Sf into a spray bottle and squirt/mist into the carb direct.You will probably stall the engine which is okay. A heavy dose in the gas can to start out with may get her running cleanly again,without a carb rebulid.