2002 Mercruiser 4.3l MPI stalling

[sterkelfamily]

This boat is fairly new to me. It is a 2002 Crownline with the 4.3L MPI and alpha 1 drive. The boat started to stall and when apply throttle would only go 1200 rpm in gear. Took to boat dealer and they said the fuel pump relay was faulty. They replaced and took it back to lake. They connected the Gaurdian alarm back up since the previous owner disconnected. Now I have 2 beeps every 2 minutes. All fluids are full. The main issue is the engine will stall when decelerating after pulling a wakeboarder. Also a couple times it hesitates before getting on plane. It starts to accelerate then bogs down and then picks up again. IAC? Fuel pump? The t-stat is faulty since the boat only runs at 118 Degrees from the delaers notes. Help please.

 

[alldodge]

This boat is fairly new to me. It is a 2002 Crownline with the 4.3L MPI and alpha 1 drive. The boat started to stall and when apply throttle would only go 1200 rpm in gear. Took to boat dealer and they said the fuel pump relay was faulty. They replaced and took it back to lake. They connected the Gaurdian alarm back up since the previous owner disconnected. Now I have 2 beeps every 2 minutes. All fluids are full. The main issue is the engine will stall when decelerating after pulling a wakeboarder. Also a couple times it hesitates before getting on plane. It starts to accelerate then bogs down and then picks up again. IAC? Fuel pump? The t-stat is faulty since the boat only runs at 118 Degrees from the delaers notes. Help please.

Howdy

The motor should run at 160 degrees not 118. Getting 2 beeps every 2 minutes can be several things. What is your engine serial number?

 

[Fun Times]

Hi, welcome to iboats!

Running at 118 degrees has probably fouled the spark plugs....Time for a full tune up if it hasn't been done recently.. If so, re-check the spark plugs.

After the new relays were installed, did that solve the problem of being able to only run at 1200 RPM or are you still stuck there as well?

Check and clean your flame arrestor, IAC muffler and throttle body.

 

[sterkelfamily]

The throttle position sensor was faulty and IAC screen dirty. After that is runs new