Carburetor issue?

[johnz26]

Hello and thanks ahead of time for your experience and advice. Here's my issue:
My twin engine 96 speedster was having issues with the starboard engine cutting out after a minute. Port engine was always pulling strong, never had issues with power or stalling. Actually ran very strong even when the other engine was down. I took the boat to the only jet ski/boat shop within an hour and the owner said he would look at it and let me know. About a week later I was told that the carburetor looked bad and needed a rebuild. He insisted I pay to have both engines twin carbs rebuilt. I thanked him for the advice but kept telling him the port side engine was not having any performance issues. Again, this engine was working fine. He kept saying that I should do both because it will fail, based on what the starboard side looked like.

After paying for the rebuild on the starboard side twin carbs and taking out for the first run, I now have the opposite happening-the starboard is working fine and the port side is now cutting off and if running, has very low power when pushing the throttle up. I feel like I was screwed and do not want to go back to the marine mechanic. I think something may have been done to the port side fuel/carb settings to make me go back and break out another $400.
Please, help out. I need some advice on what I could possibly check or adjust to get it working like it was running prior to taking it to the shop. Any screw adjustments I should check?

 

[POPPS]

It's not going to be easy, you need to set the low speed pilot screws to their factory settings (that you find on line, I don't recall them, they will be around 1 to 1 1/2 turns). You will be literally upside down, you no doubt will have to remove the air box to get your hand down and below the carb to get at the pilot screws. The connecting sync arm will also be in your way. Also, get a wide mirror and check that both throttle plates are open exactly the same amount.

Also check that your throttle linkage is set properly, at full throttle, the throttle plates should be about 2 mm from vertical so that there is no stress on the cable, also that you get the most from your carbs.

Since the starboard runs, check that the tach reads close to 3000 rpm, then with your mirror, set the idle screw on the bad carb so that the throttle plate has the same opening (after you have set the low speed pilot screws), It's very very hard to get down there, the true best way for access for all of this is to remove the motor cover (it will take 2 of you), that will make it physically easier, (you may not be totally upside down, and kill your back).

And with the motor cover off, you just may want to remove the bad carb and go through it yourself, if this (setting/sync'ing move does not work).

After you start your bad carb, you want it to idle at 3000 as well, and with the cover off, you can get at the idle screw much easier.

I know this sounds like a lot, but I have done this, jet boats are terrible to work on in the hull, ease of access is everything. I usually also make platforms at the back of the boat to allow me step up and get up into the hull. I also take my shoes off to give my feet more space/things/hull to step on for balance and leverage.