50 litre Merc cutting out above 3000 rpm fuel gauge erratic

"I've got 7 hrs or so this

"I've got 7 hrs or so this year on a 1998, carbeurated 5.0 L Mercruiser. For the last 3 hours, the engine has been cutting out over 3,000 rpm. When this occurs, the fuel gauge starts to bounce on me (not caused by the boat speed fluctuating because at first, the boat speed doesn't). If I insist on keeping the throttle on or try to accelerate, the motor dies. So far, it restarts right up. I'm thinking I have an electrical problem because the fuel gauge needle is the only one that bounces around.

Any suggestions?
Is the fuel pump in tank?
If so, is the pump and sender one unit?

Thanks,
Jeff"

"What boat?
Your fuel pump is

"What boat?
Your fuel pump is likely an inline electric type.
If you follow the fuel hose from the tank fitting it will likely go to a filter then to the pump which will have an electrical plug on one end.
This should all be mounted on the front stbd side. The filter will be low and is likely a white throw-away type that looks like an oil filter.
Likely it quits due to fuel starvation. I would change the fuel filter, including a second small porous type that may be installed at the carb inlet.
I don't think the gauge issue is related, as it's wiring does not pass through the engine wiring harness.

Rod"

"I have a 1990 stingray with a

"I have a 1990 stingray with a 5.0L mercruiser and my boat was doing that same thing,I rebuilt my carb and changed both of my fuel filters now it runs fine."

"Jeff, let me know if you get

"Jeff, let me know if you get that problem fixed. I have been fighting the exact same issue for a while now. Rod told me to check the vent hose for any obstructions. I replaced it and will see if that fixed mine Friday. I changed everything from the tank to the carb adn it still does it. Just dies after 3000 rpms. If I pull back all is good, if I don't it will shut down but then restart with no issues. I will let you know if that vent hose fixes mine."

"I have a Chaparral 205 LE. I

"I have a Chaparral 205 LE. It's a cuddy. The hour meter is new but I was told that it might only have 150 or so hours on it at the time I purchased it in Sept '06 (apparenlty it was a repo that sat in a compound in Arizona for quite some time - this is the 3rd summer of recent and constant use). Cosmetically, it is in terrific shape.

Thanks to the other poster's too. I'll let everyone know when/if I fix the problem and what the solution was. The fuel gauge makes me think it's electrical. The fluctuation is quite noticeable and like I said, it does this as soon as I hear the engine start to hesitate but before the speed or momentum changes so I don't think it's the fuel sloshing around. I just topped it up and I'll see if that makes a difference to the gauge movement.

I pulled the fuel filter and emptied it into a jar to see what I had, there was a quarter teaspoon or so of water at the bottom. I put the old filter back in (will replace today). In the driveway, with the ears on, I revved it to 3500 very briefly (2 - 3 seconds) and there was no hesitation. That gives me only a little hope and i'll lake-test it this week and see how it goes.

Jeff
Nelson, BC"

Jeff;
Be careful what you do

Jeff;
Be careful what you do on the muffs.
Merc says don't run it above 1500 rpm in neutral.

Rod

Don't consider what it doe

Don't consider what it does revving it up on the trailer. If it is a fuel issue it will not screw up until it has a load on it. Revving 3500 in the driveway uses the same amount of fuel as idleing around in the water. I hope I got mine fixed and will see tonight. I checked the vent and it had a low spot which had fuel sitting in it. I think it was enough fuel to get air in to run without a large demand for fuel. We will see.

"So I vacuumed out the cuddy a

"So I vacuumed out the cuddy and washed the hull and all is good now. Just kidding...Rod Stewart, you were exactly right. New spin on filter/separator and i took her slowly all the way up to 4500 rpm tonight on the lake - a couple of times. Thank you Rod and the other posters too. Next time I tinker, I'll look for the filter on the carb inlet. Happy boating and thank god for the internet and forums. Rod, you post a lot is this your forum? Are you a moderator? You're obviously a marine mechanic. I really appreciate you taking the time.

Jeff"