Stalling issue while idling...496

S

SunDogs

New Member
Sep 7, 2014
11
North Port, Florida
Boat Info
2006 Amberjack 270
Engines
496 Mercrusier w/ Bravo III
Hey all- new here this past fall as I got my first SeaRay at the end of last summer: '06 Amberjack 270 w/ 496. I've been researching an issue we started having but can't seem to find quite the same issue and was hoping for some advice/ direction. Engine stalls after idling for a while, either stationary or no wake zones. Have to let it sit 15-20 minutes or so then can start up again. Have no problems when it first starts out, just after we've been running for awhile. Engine temps are fine, run the bilge blower to keep air circulating. And it doesn't do it all the time but often enough to be annoying. No other issues running or starting. Similar issues I've been researching point to IAC, fuel filter, or something like a vapor lock, but symptoms are not quite the same. Any pointers on what else to check on would be greatly appreciated.
 
Sounds like a bad IAC. Easy to replace. If it turns out not to be the IAC leave the new one on and keep the old one as a spare.
 
JimT said:
Sounds like a bad IAC. Easy to replace. If it turns out not to be the IAC leave the new one on and keep the old one as a spare.
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I'd tend to agree. Although in my experience when they go, they go, not an intermittent type thing. That said it's a cheap part and a 5 minute job. Worst case you have a spare part that you need to keep on board anyway.
 
Thanks guys. Since IAC was one of the probables, figured I'd start there. Got it ordered. And thanks for the muffler tip. Didn't know about that part. I'll update once I get the new IAC on.
 
SunDogs said:
Thanks guys. Since IAC was one of the probables, figured I'd start there. Got it ordered. And thanks for the muffler tip. Didn't know about that part. I'll update once I get the new IAC on.
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You can get them for half the price or less at NAPA.
 
I keep a NAPA IAC on board. I think it was around $60 though I hope to never need it with annual muffler changes. I've heard rumblings of possible incompatibility with these marine engines. Anyone running an aftermarket IAC currently?
 
I was chasing a rough idle/stalling issue at low RPM's last year. I changed IAC, spark plugs, cap and rotor and still ran bad. Turns out my riser was bad and I was getting water down into a cylinder. Once the RPM's picked up the pressure kept the water out. If the IAC doesn't fix it, check your oil for water and pull your plugs to make sure they are dry. If your risers and manifolds are original it is probably time to change them.
 
So finally got a chance to get back on here. Replaced IAC, muffler, got throttle body cleaned while it was open (thanks for all the tips guys).
Took her out ran great, idled for about 20 minutes....and stalled. Same scenario- sat for 20 minutes started up and off we go again. Again, no issues when I opened it up, runs smooth and before the stall idle is fine no surging or sputtering, just dies.
Manifold/ risers were done (supposedly) before I bought it last year. Will check on plugs and water in the oil tomorrow. Thanks again guys.
 
Last edited:
Having a similar issue now with my 496. Was told to look into the fuel pressure to see if regulator or cool fuel module/ pump is going bad. I have the DTS so I do not have an IAC.

I checked the fuel rail pressure at idle and it was at 44 psi as it should be. Plan to try to test it at higher throttle tomorrow.

Was as told if pressure sags, the vapor lock could occur from heat build up and pressure is not high enough to prevent it. Also was told the reformulated fuels used in fall and winter will make it happen as well. I just bought fuel and was told it was from last fall at the marina. We only have ethanol fuels here.
 
I am having the same issue with a 2007 36 sedan bridge w/496s and DTS. Starts and idles great for 5-10 minutes then stalls and wont restart for 15-20 minutes. How did you folks resolve this issue???
 
Peter White said:
I am having the same issue with a 2007 36 sedan bridge w/496s and DTS. Starts and idles great for 5-10 minutes then stalls and wont restart for 15-20 minutes. How did you folks resolve this issue???
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Does your DB have the cool fuel 3 modules?

Have they ever been replaced?

A fuel pressure test is a good first start. One sign of the paint chip contamination is higher than normal fuel pressure.
 
On my old boat with twin 8.1s I had the same issue on the starboard. It was a gremlin for sure. In the end, I swapped the crankcase sensor from the port and the problem followed. Hence solved. The sensor is on the block just above the trany. What happens is there is a magnet on the end that if it cracks, you get this stalling to ultimately dead engine. The newer sensors have the magnet inside the end. When they are placed back in, there is a slight adjustment either up or down so the tip is just a fraction from the crank. If it touches, you'll hear the rubbing. So adjust up very little. Hopefully this is the issue and can be resolved very easily.

Why it shuts down after 15min, on mine was as the temperature increases it effected the broken magnet which then it can't read the flywheel turning.
 

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LG111 said:
On my old boat with twin 8.1s I had the same issue on the starboard. It was a gremlin for sure. In the end, I swapped the crankcase sensor from the port and the problem followed. Hence solved. The sensor is on the block just above the trany. What happens is there is a magnet on the end that if it cracks, you get this stalling to ultimately dead engine. The newer sensors have the magnet inside the end. When they are placed back in, there is a slight adjustment either up or down so the tip is just a fraction from the crank. If it touches, you'll hear the rubbing. So adjust up very little. Hopefully this is the issue and can be resolved very easily.

Why it shuts down after 15min, on mine was as the temperature increases it effected the broken magnet which then it can't read the flywheel turning.
Click to expand...
LG111 said:
On my old boat with twin 8.1s I had the same issue on the starboard. It was a gremlin for sure. In the end, I swapped the crankcase sensor from the port and the problem followed. Hence solved. The sensor is on the block just above the trany. What happens is there is a magnet on the end that if it cracks, you get this stalling to ultimately dead engine. The newer sensors have the magnet inside the end. When they are placed back in, there is a slight adjustment either up or down so the tip is just a fraction from the crank. If it touches, you'll hear the rubbing. So adjust up very little. Hopefully this is the issue and can be resolved very easily.

Why it shuts down after 15min, on mine was as the temperature increases it effected the broken magnet which then it can't read the flywheel turning.
Click to expand...

Espos4. I do have the cool fuel 3 modules. Sea ray tells me they were both replaced. Thanks for the reply!

LG111. Great info thanks. I will swap the CPS as you suggest when she goes back in the water next month and let u know the results. Much appreciated
 
Hello,

Peter was your issue resolved? I am having the same issue, no DTS.
 
There was a short in the wiring connector near the cool fuel 3 module. it was not the connector to the fuel pump itself, it was the connector that goes to the fuel control valve mounted to the Port fuel tank. I replaced the valve but there was no improvement. In chasing the wires I found the connector just above the cool fuel 3 was partly melted. Once the connection was repaired the problem disappeared. Check the wiring in this area and to the tank mounted valve
Fuel control valve.jpg
and let me know what you find. Good luck.
 
I am told these valves can fail. You may want to try swapping it out if the wiring is all in good shape.
 
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