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omc tripple cut out
alright here's my question. I have a 93 omc 3 cyl. It has 1985 75hp carbs on it. When I take off it hops on plain then cuts out at full throttle. If I back out of the throttle just a little bit then it will stop cutting out and run fine but when you lay the throttle open again it cuts and sputters. If I bump the electric choke it pours the coals to it and it lays down and runs but cuts and sputters when your not bumping the choke. These carbs did the same thing on another motor. What's causing this? Thanks.
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skipping
Sounds like either water in your fuel or some trash in the carbs.
Either way it's fuel related if the choke helps.
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check the float level in the carbs and the sync of the carbs and throttle linkage
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Engine cutting out
If the fuel system is clean and their is no air being sucked into the fuel line then one place you might look at if the carbs are fixed high speed jet is the actual high speed jet size. You might compare them to the old carbs. The indication you discribe seems to point to leaning out when your at full throttle. When you bump the choke it make the mixture richer and your power comes back. Only a thought.
Alan
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at the marina we usually rebuild thecarbs toget out the crap in the cercuits,,, and especially puull the top body plug overthe idle circuits to clean and re-seal the body plug with epoxy as they can suck air threw them,,,
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It sounds like simple fuel starvation. How about attaching a fuel pressure gage and see if the pressure falls off at WOT?
Jeff
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Fuel
Good point Jeff. It might be a fuel pump issue that is causing the issue. If you can squeeze the primer bulb and it picks up this could then show that a filter might be pluged or a pump going south.
Alan
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The fuel pump is fine and the main jets aren't lean because I've put jets in them fat enough it would flood and that didn't solve the problem. It's not the fuel pump because it did the same thing when I put the carbs on my motor. My motor runs just fine with my carbs so I know my fuel pump is fine. Replaced all of the fuel lines and I know they aren't leaking. The problems started with the carbs when we started modding the motor. The more rpms we gained the worse it got.
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Rev Limiter
Anyone know if there is a rev limiter built into the ignition system?
Alan
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a guy here had a simalar issue with a fishing boat, it was a needle and seat issue from memory. depending if you have the old style carbs with butterfly choke or newer style pull the carb apart flip it up side down blow air through the fuel line and lift the float up and down makre sure that the needle is seating.. dont use a compressor use a long piece of clean hose and your mouth.
with the rpm limiter if its the old school electrics with the white box its unl. if its the black box some are some arent..it will have it written on the cdi the limit
hope that helps?