What is the Johnson 1949 seahourse air needle setting?

I have a question on the Y needle settings for a 1949 Johnson Seahorse HD25 motor. This one is a 2.5 hp two cylinder engine.

The gas line from the carb goes to an odd looking upsidown Y air mixing that has a hole in the center of the Y. On one side is a needle for maybe Air, the other side of the Y is the gas line. I got the motor running and adjusted the needle fulling closed and several turns out. I settled on one full turn. It doesn't make much sense to me as the center hole is sucking in the majority of the air. What is the suggested setting and would someone use this as a choke. Looks neat just the same.

The Y shape is on the right side of the picture. The needle is just a long stem with an angle at the bottom.

Thank you in advance for your response. Regards, john

Re: What is the Johnson 1949 seahourse air needle setting?

John, Initial setting on the idle screw is 3/4 turn out from lightly seated. The high speed adjustment is 3/4 to 1 turn off lightly seated. (The wheel on top of the engine with the numbers). Pushing this wheel down is the priming mechanism. I think on a cold engine, you pump it about 3-5 times. There is no choke on the engine. I've had a few of these. Good little engines!

Re: What is the Johnson 1949 seahourse air needle setting?

It is an idle fuel needle, not air. The Y fitting actually acts like a mini-carburetor, drawing air through the opening and fuel from the pipe, regulated by the needle setting. There is a rotary valve built into the engine at that point.

Anyhoo, on the 2.5 the final setting on the needle will be very close to 5/8 turn open, and is very sensitive. Begin with 5/8 and tweak it from there in tiny increments if needed. Adjust it only at idle speeds.

Re: What is the Johnson 1949 seahourse air needle setting?

Thank you guys. This morning, the motor started on the first pull. Time to locate an old repair and part manual for future references. It really is an enjoyable motor. I appreciate your assistance.

Regards,
John

Re: What is the Johnson 1949 seahourse air needle setting?

Success is sweet.....

Re: What is the Johnson 1949 seahourse air needle setting?

Sweet. I have a few of those old HD-25's but have never tried to get them working yet. This gives me hope to try. Way to go