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496ho's will not run past 3500 rpms?

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496ho's will not run past 3500 rpms?

Old 08-06-2013, 04:45 PM
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Default 496ho's will not run past 3500 rpms?

Boat ran fine up untill yesterday noticed that max rpms were like 3500 when she usually runs 4900-5000 rpms on both engines. talked to mechanic and his first guess was safety/ neutral switch bad? i am not getting any audible alarm noises but when running at 3500 max the engines are back fireing like i'm hitting the rev limiter? anyone have any insight on this issue?
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Old 08-08-2013, 09:25 PM
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Had similar issue last year with my 01 272 with 496ho. Ended up being water in fuel/water separator and fuel pump went bad. Once the fuel pump was removed found it was plugged with plastic shavings from the tank. Must of been In the tank when boat was manufactured. Also installed a in line fuel filter before fuel pump. Problem solved. Couldn't get boat over 3500 rpm and would backfire bad before we figured it out
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Old 08-09-2013, 01:37 AM
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wwolfe my boat has twin engines and both of them have same problem, both have new fuel/water seperators on them don't think my problem is same as yours, thanks for the reply.
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Old 08-09-2013, 06:18 AM
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If both of your engines are suddenly having the same issues I would be seriously looking at the fuel system (debris/clogged filters or water in fuel and Filters,pick up obstruction, fuelpump pressure)...if only one engine was acting up the list of possibilities could grow quickly but twins at the same time

Years ago we did a full service on a boat after launch. Boat ran fine (twins) - owner went out for the weekend and was towed back in & totally p!ssed.... in his travels he bought a partial tank of water
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Old 08-09-2013, 09:19 AM
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26 sonic, my friend experienced the same problem as you with both (496HOs) motors. He/we ended up replacing both fuel pumps...problem solved. No codes on the scan we ran. Theory is that ethanol ate the pumps over the winter.

There are fuel screens built into the pumps that you can check before replacing the pumps...his did have some debris.
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