That could be it, I assume it has an electric pump, and with low voltage the fuel pressure may drop off. have batteries and alternator tested.

It has an electric pump in the vst tank. It seems the two go together, volt gauge down about 10 drops out under load but volt gauge up about 13 runs fine.

The ing will not operate properly below 11 volts either. Sounds like you are on the right track. Check and clean all grounds, there are a mess of them on the bell housing bolts, they are prone to corrosion.

See, we get fixed on these scan tools. Basics first, test everything you would on a non efi engine if u scan with no codes.

The problem seems to be intermitent. It ran fine the other day as I mentioned, then we went back out after dinner and it was not.

I mentioned the voltage change, when it runs fine the volt meter on the dash reads 13 when it doesnt it stays around 10. This happens on the first run out or later in the day not reason for the condition.

So no one around me tests marine alternators. I went to about 3 places and called around 6. So I tested it before I took it off, it was putting out over 14 cant remember the decimal. My volt gauge on the dash was at 13 again though. I may have to wait for the problem to happen again and check so I will be boating with my meter.

Question for everyone though is as I put my alternator back on I want to check all the connections. I found at the starter, a block or something and want to know what it is. The post that the 12 volt pos from the battery goes to has a block conntected to it also. The block is removable and on its other end the orange wire from the alternator is attached. It is about the size of a die, or piece of bubble yum. What is this?

Cant remember exactly what that block is for. sounds to me like you have an intermittent alternator problem. A bad battery is a bad battery in most cases, doesnt come and go. Could be a loose ground also, but I dont think that would make your gage drop to 10, it would either be zero or 14+

I would just like to know what that block is for the sake of knowing if nothing else.

I hate to just throw an alternator at it for 220 bucks. I am going out of town with the boat Tuesday so I have a few days to locally put the boat on the water and try to get the problem to pop up again. I will keep the meter with me so then I can check and see if the alternator is down or something else.

What about a loose belt? I have not heard one squealing or anything but will make sure it is tight when it goes back on. I will also be cleaning all the connections and making them tight.

Just an FYI, check the battery switch also, just heard of something similar happening.

Why can no one test your alternator??? same connections as an automotive only the marine are shielded to prevent spark

Did you try a starter/ generator/ electrical rebuilder to bench test?... just putting a suggestion out there

dbelectrical.com

spiecherlane....I have not tried a rebuilder to bench test. I found one and will try Monday. The automotive place saud that there were not connections were the computer told them to hook up.

The boat degfinetely runs fine, normal when my dash volt meter is at 13. I have not been able to get it to do it since I re did all the connections.

Where does the volt gauge on the dash get its reading. If I turn my key on it reads 10-11, but battery reads 12.8.

I start the boat it goes to 13 and the alternator reads 14.?

I have not been able to recreate as I said to see what the readings are when it is running bad.