I bought a mikuni carb from the boat dr earlier in the year. I have still not got it tuned right. I have heads cam exhaust and carb. They put the correct jets in it before they sent it to me. The motor idles great and runs good from mid range to full throttle. My problem is when I am idling and grab a hand full of throttle. The motor spits and sputters and will die unless I let off the throttle . if I just ease into the throttle it is fine but if I grab a handful it does it. When I first get to the water it does great. Takes off good and doesn't sputter for about the first 2 or 3 minutes. After that is when it starts. And if I run it for a while and turn it off it is hard to get back started unless it sits for a while. Does anyone have any idea what this could be?

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Also I have turned the air/fuel screw every which way possible and I have played with the acc pump and it doesn't make and difference

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What jets are you running?
ACC pump nozzle spraying directly on the jet needle? If not the fuel isn't' being splattered off the needle to help atomize it off idle to get the velocity up through the carb.

What engine for you have it on and what size carb? 34mm or the 42mm

The tuning manual says if you can't easily adjust with the air screw then your pilot jet is the wrong size.
I have the manual damn near memorized and still can't get my motor right. I'm saving for a a/f meter. And waiting for some cooler drier weather too bc my motor runs much better in it on the current tuning.


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http://m.ebay.com/itm/272045926152

Flint87 this is the afr gauge I bought and used throughout the time I was tuning my motor.
Worked great for what I needed it for

I took the boat out again today and it ran the same. But when I loaded it back up on the trailer it died. When I went to start it back I noticed a flame coming out of the exhaust. I shut if off real quick and it continued to burn for a few seconds any ideas

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Could be a few things, you never answered what carb you had and if this is on a big block or small block

Mine does the exact same thing you are describing. I just put mine on and haven't had a chance to try fine tuning. Seems to run perfect other than that. However, my motor did the same exact thing before any mods, when it was stock. My buddy has a stock 35 that does the same thing also. Stock fuel pump or air in the line somewhere? I have no idea but I'll be getting to it soon to figure it out.

It's a mud buddy 35 and a 42hsr

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