Nissan 2.5 with 3.5 carb?

I recently aquired a Nissan 2.5A2 2-stroke outboard from a gentleman who could not get it running. He bought a carburetor for a 3.5 outboard which obviously is jetted too rich. When I got the motor it would not get up part 1/2 throttle without bogging down from being too rich. I know the proper way to fix this would be to order a rebuild kit for a 2.5 because from my understanding the only difference between the 2.5 and 3.5 outboards is the carb jetting.

As a temporary fix I moved the clip on the main jet needle up one notch to lean out the high speed mixture. From my understanding this should be OK but I'm curious if anybody has any experience with this possibly being too lean for the motor?

Cliff notes:
Nissan 2.5 with 3.5 carb
Engine ran too rich at above 1/2 throttle and bogged down
Moved the E-clip up one notch on the main jet to lean out high speed
Wondering if this will be too lean for motor?

Re: Nissan 2.5 with 3.5 carb?

It would really depend on what carburetor he actually put on. There are different carbs for the different engine blocks. IE, an A2 3.5 carb will fit onto a A2 2.5 and work perfectly. But you can't cross model types.

Re: Nissan 2.5 with 3.5 carb?

The carburator works fine on the motor like I said it just runs very rich above half throttle. From my understanding the only difference between the two carbs would be the jetting. Is that correct? I haven't tried this carb setting for risk of damaging the motor but I'm going to run it for 30 minutes or so and pull the plug just to check if it's running dangerously lean.

Re: Nissan 2.5 with 3.5 carb?

Is that correct? No and/or yes.

"It would really depend on what carburetor he actually put on. There are different carbs for the different engine blocks. IE, an A2 3.5 carb will fit onto a A2 2.5 and work perfectly. But you can't cross model types."

You have an A2. If he put on a 3.5 carb off of a 3.5A2 your fine. If he put on a 3.5 A carb or a 3.5 B carb it will not run correctly. Could you enrichen or lean it byy adjusting the needle? Yes. Will that make it correct? No. I'm not saying it could not possibly work. I'm just saying it is unlikely that it will work as it is supposed to.

Re: Nissan 2.5 with 3.5 carb?

OK thank you for the advice! I'll keep my eyes peeled for the proper carburetor. This little outboard is too useful and convenient to waste.