Small Engines (Lawn Mowers, etc.): 2 Stroke Choke Problem, mixture settings, motor model

Question
Ben,
I read your profile and although boat motors didn't appear to be your major area of interest, I thought that my problem is basic and you could give me some help. I purchased a used Nissan 3.5 HP boat motor (Model #95916, NS 3.5A2) that was in good shape except that it had been stored for a couple years by its previous owner without the fuel being drained from the tank or carb. I gave the motor a complete cleaning -  removed and cleaned the gas tank, gas line, replaced the in-tank filter, and cleaned the carb. as best I knew how. I added a new plug and fresh fuel and the motor starts every time. My problem is that there is a choke lever that you are to use for cold starting. Even when the motor has warmed I can't move the choke lever to the run position without a stall. The motor will only run with the choke closed and in that position, when I try to increase speed, it stalls. I would really appreciate some guidance concerning what to look into. The float and needle valve are clean and all the carb parts look good to me. Why will the motor only run with the choke closed? My thinking is that I have a fuel delivery problem.  Why isn't the motor getting fuel unless choked?
Thank you!!!

Mike


Answer
Mike
Just a suggestion but been there.
I would determine if your timing and carbs are synchronized or not.
This is done with linkage adjustments with motor off. Manual will show how. Very simple procedure but important. If not fuel will not fire at the right time.
Choke should only effect a cold or fuel starved motor.I'd start by looking for a leak, if its sucking air somewhere its not supposed to be, that could result in the problem you are having.

did you change the mixture settings?if the Choke, primer setup on engine is not working properly, check valves in fuel line/bulb are back draining. Fuel pump could be partially clogged or weak, filter almost clogged.