Engine misfire and hesitation, stutters coughes

[boatnfly@att.net]

OK here is a good one. I'm running an 07 SV211 w 5.7L PCM. Raw water cooled. Last two times out, boat ran great. Skied, sky ski'd, surf no problems on perfect pass of off.
But, last two times, both days, out since 9am about 3 o'clock running down the river all of a sudden the engine looses power, catches looses power, does this a number of times, a few times it coughes. Never quits. I back off the throttle to neutral and start again, 1 minute later it happens again. It has happened off perfect pass (system off) it has happened witht he system on. It has happened with a skier and without.
I shut down give it a few minutes go again and it happenes. I tried wide open throttle or running 1/2 speed still the same. The killer is all day it ran beautiful, why now? If it was the gas why not earlier? I believe it has nothing to do with the cruise control, as i mentioned it happenes even with it off. I'm running straight and level on a river. if there was water in the fuel control again why not earlier?
This coming from one of the most non mechanical guys on the water, so any help in laymans terms would be appreciated
John

[Gasman87]

Ours did this the other day as well , we never run her below half a tank (55 gal tank) but we ran the crap outta her!
Then her very first stumble(615 hrs) EVER ! Changed fuel pump , problem solved ????
Could be the same ?? Let us know !! Good luck !

[Chexi]

^ This sounds like a common MasterCraft problem. They have had a major problem with their fuel pump, which uses the fuel surrounding it to cool the pump. When the gas tank gets below half, there is no gas surrounding the pump, and the pump overheats and eventually fails. I hope Nautique has not gone to the same design.

[xrichard]

Could be the fuel pump...you could put a gauge on it (pretty cheap / easy) to see if it's building pressure and holding it.

CC was using the FCC in '07 (and still is) which keeps the high pressure pump out of the tank. MC has had a problem, but more likely caused by a cheap pump than an in-tank/submersed design--otherwise we'd all be burning up pumps in our cars since they cars use the same basic design as MC.

[H2O]

PCM issued a service bulletin (#SUP2009-01) to dealers for 07-08 Excaliburs S/N 470001-485993 that may apply to your motor. It is to change the cam retard specification (distributor rotation) to prevent/correct missfiring. The proper Diacom Software must be used to change this setting (dealer).

[boatnfly@att.net]

i opened the little drain plug on the bottom of the Fuel control cell, both water and gas drained. 3 different days out now, same conditions as the other time but no more problems. I think the problem was water in the FCC, this did the trick