View Full Version : Just got my X-9 and Day 1...problems

09-20-2009, 09:56 PM

I just purchased my first Mastercraft. It is a 2002 Mastercraft X-9 with the Predator 310. Got it on the water today for the first time and I have having some issues I was hoping someone may have some input on.

It idles around 500 rpm which seems low (my opinion) but will at times be around 1100. It will die when you pull off the throttle and back to idle but not every time. It will run smooth pull it out of gear and idle it up. It has one other issue too while running. It will stall out and die when running at a constant speed. Anywhere between, 10mph - 20mph. If you feather the throttle quickly back and forth before it dies it will keep running.

I have searched the forums and it appears the place to start is the IAC but would like some input from anyone more versed on these engines. It is a Indmar 310 TBI. Please, note the fuel pump was replaced right before I bought the boat and it was having a very similar issue.

Thanks, Berry

09-21-2009, 10:47 AM
First thing, does it have old gas in it? My X2 had 4-5month old gas when I bought it and ran like crap. Most of the same issues, except engine dying at constant speed.

09-21-2009, 04:30 PM
It has fresh gas. I am really leaning toward the IAC based upon research. Anyone? Thanks.

09-21-2009, 04:32 PM
I meant on that last one does anyone know what model GM truck I can get the IAC from?

Tom Jones
09-21-2009, 06:28 PM
I replaced the IAC on my old boat based on some advice from MasterCraft. It cost over $100 and didn't fix the problem. Your engine could have a problem with a sensor or IAC or MAP or thermostat or timing or a number of things. Based on my experience I would have the dealer put it on the computer to diagnose the problem rather than guess.

09-27-2009, 08:53 PM
How long can you leave gas in the boat without adding stabilizer? before it causes problems?

09-27-2009, 09:11 PM
I meant on that last one does anyone know what model GM truck I can get the IAC from?

The number is on the part but I would really have someone run diagnostics before replacing any parts. The IAC can be functioned at that time, manually. Also, it will give you a baseline for the motor, especially if you check/verify timing (I would do that NOW), compression, vacuum and cylinder leakdown.

Have you looked at the cap/rotor/plugs/wires/grounds/battery terminals/cable clamps/flame arrestor, etc? If the replaceable parts are all original, they're all past due for replacement. The rest should be checked on a regular basis and the flame arrestor is the single most neglected part on all of the boats I ever worked on.