Crusader 502xli runs perfect for 15min then suddenly dies

Hi, I have a 2005 crusader 8.2l 502xli. After 15 min of running perfectly at 3400rpm, it suddenly dies. No sputter, just like flipping a switch. It will start again after a min or two but the starter motor really struggles to turn the motor, acting like it is almost locked up. When it does start to turn it fired right back up but will die again if I take it above 3000 rpm. It will run fine for hours when below 2500rpm.


I have replaced the fuel filter, fuel pump, coil and wires and plugs. Gas in tank is about 12 months old but was stabilized. Starboard motor is on a separate tank and had the same age gas and runs perfectly. I have also checked for fuel leaks and have ran the boat with the fuel cap off...still having same issue. I've also swapped the ecms from starboard to port and no difference.


Any ideas? Could it be water in fuel? Or perhaps the ignition module or rotor/cap/distributor? Thanks so much in advance for any direction.

I had this happen on my merc at one time. Same year roughly. Check your power source. I had a bad cell on a battery cause this, this could also be where your hard restart comes from.

Nick

nicholas0 said:

I had this happen on my merc at one time. Same year roughly. Check your power source. I had a bad cell on a battery cause this, this could also be where your hard restart comes from.

Nick

Click to expand...

Thanks, I didn't think of that. I have 4 batteries per motor but they are old, probably 6 years now. They start the motor fine when cold though so I never thought they would be part of the problem. Alternators are putting out 14v when running.

Could it be an intermittent battery failure? I guess I can swap out the old batteries for new ones, that's a simple test/job.

Thx

Mine would run great for a short while after leaving the dock, because the shore power and charger had it capped off, but shortly into the trip even though the alternator was putting out proper voltage battery just wasn't absorbing it.

New batteries fixed my issue.

Good luck

Ensure all the battery lugs/connections are clean, secure, and tight. When restarting did you try and use the "parallel" switch to use the other battery bank (if equipped) ? At some point, need to monitor fuel pressure but the slow cranking does not track with a fuel problem.

Mulletwagon said:

Ensure all the battery lugs/connections are clean, secure, and tight. When restarting did you try and use the "parallel" switch to use the other battery bank (if equipped) ? At some point, need to monitor fuel pressure but the slow cranking does not track with a fuel problem.

Click to expand...

Yes I used the parallel switch with same result. Motor almost acts as if it is locked up for a few secs after it dies and I try to restart it. After a few slow revolutions it starts more rapidly and then fires up and runs just fine, below 3k Rpm. If I bring it back up to 3400 (cruise rpm) it does again in a min or two.

I think ink I will swap out the batteries tomorrow to rule that out. They are old and need to be replaced regardless. Thanks for the tips gentlemen....

Interesting problem. Sounds like a classical case of an electrical component heating up and slowly resisting current flow. Some things to consider are a faulty circuit breaker, failing ignition relay, or (somewhat rare but happens) the tachometer grounding out and precluding current going to the coil. A good first step is to attach a multimeter to the circuit breaker terminals and monitor voltage. Easy to get to the breakers, just open the electrical box attached to the exhaust manifold and attach the alligator clip on the downstream terminals. Looking forward to a success story.

Could be one of the relay's or that wonderful oil pressure switch that controls the fuel pump.....a voltmeter (or two) connected while its running should help to isolate the problem...

makomark said:

Could be one of the relay's or that wonderful oil pressure switch that controls the fuel pump.....a voltmeter (or two) connected while its running should help to isolate the problem...

Click to expand...

Turns out it was just water in the gas. Replaced a worn seal on the fuel cap that must have been letting in rain water.

removed a few gallons of fuel from the bottom of the tank, added 4 bottles of HEAT additive and filled up tanks with fresh fuel (from 1/4 full). Running 100% now.

thanks to everyone who contributed. I guess I now don't have to worry about many of these parts failing as I've replaced so much before trying the easy solution!

scostgal, what ever happened with old batteries, were they replaced? It's just a matter of time,6 years??

johnnygjr said:

scostgal, what ever happened with old batteries, were they replaced? It's just a matter of time,6 years??

Click to expand...

Hi, yes I replaced all the batteries with new diehard marine batteries....but I was still having the problem until I got rid of the old gas.

I stand behind those diehard batteries....the ones I replaced were almost 7 year old lead acids and they were still holding a charge when I took them out. Pretty impressive.