I own a searay 260 sundancer, with a 454 mercruiser engine, my issue is when we hammer down and get on plane and level out about 3200 rpm's she's on top of the water fine, no indication of any problems, then all of a sudden the motor shuts down like someone turned the key off.no overheating, no nothing. any ideas? ugh.
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engine problems
- Thread starter figs11
- Start date
I had a similar problem with one of my Crusader 454s. was like the ignition switch was suddenly turned off. Turned out to be a break in the purple ignition wire from the bridge. Replace the wire and all has ben weel X 3 years.
quote:
Originally posted by Billylll
Check the engine harness where it connects the vessel to the engine. I have seen this connector get crud or loose and cause similar problems.
Bill
I have seen corrosion where the wire joins the connector pin also.
Connector/pin issues can drive you nuts.
When it quits, before you touch anything else, meter the coil primary hot to ground.It should be near battery voltage.
You can also cycle your Kill Switch a few times (engine not running) and see if that helps. At least on our EFI MerC, if the kill switch is Open (stopping the engine) it WILL crank, but not start, and one evidence it was Kill Switch is the instrument panel looks like the Key is OFF.
PS - Glad you have the BIG engine in that! The 5.7 MPI does OK, but nothing exceptional.
PS - Glad you have the BIG engine in that! The 5.7 MPI does OK, but nothing exceptional.
Originally posted by Billylll
Check the engine harness where it connects the vessel to the engine. I have seen this connector get crud or loose and cause similar problems.
Bill
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Me too.
Does it restart right away every time or just sometimes or...?
Time for the Wiggle Test.
If it cranks but doesn't start right away , can you hear the fuel pump prime when the switch is turned to ON?
-If no pump noise, with key ON ,wiggle hard all the cables and harness connectors near the electric fuel pump and it's relay and fuse on top of the engine to see if the pump activates briefly.
-If you can hear the pump, with key held to Start still wiggle all the harness wires and connectors and relays and fuse holders on the engine and see if you can get it to fire.
On the other hand, if you don't have any trouble starting it right back up , leave it running and do the Wiggle Test to see if you can get it to cut off at the dock. Engine 1st, then include wires on the ign switch, lanyard switch and battery cables & grounds, etc.
If any Wiggling is successful the problem is very close to what you were touching.
One of my MPI's
had an occasional annoying brief cutout issue when cruising along for 2 yrs . Nothing ever showed on my marine diagnostic scanners.
Finally, the Wiggle Test led to a connector to the fuel pump relay which had 1 very slightly bent pin - hard to tell it wasn't straight. When straightened , no more problems of that nature for the past 8 yrs, ...though the fuel pump on engine 20 amp spade fuse has blown at start a couple times over the years since( 30 seconds to replace.)
Both the fuel pump and ECM/ECU have on-engine fuses that could have slightly iffy connections though other connectors are more likely. Don't neglect checking on-engine grounds as well . There are several at least.
Time for the Wiggle Test.
If it cranks but doesn't start right away , can you hear the fuel pump prime when the switch is turned to ON?
-If no pump noise, with key ON ,wiggle hard all the cables and harness connectors near the electric fuel pump and it's relay and fuse on top of the engine to see if the pump activates briefly.
-If you can hear the pump, with key held to Start still wiggle all the harness wires and connectors and relays and fuse holders on the engine and see if you can get it to fire.
On the other hand, if you don't have any trouble starting it right back up , leave it running and do the Wiggle Test to see if you can get it to cut off at the dock. Engine 1st, then include wires on the ign switch, lanyard switch and battery cables & grounds, etc.
If any Wiggling is successful the problem is very close to what you were touching.
One of my MPI's
had an occasional annoying brief cutout issue when cruising along for 2 yrs . Nothing ever showed on my marine diagnostic scanners.
Finally, the Wiggle Test led to a connector to the fuel pump relay which had 1 very slightly bent pin - hard to tell it wasn't straight. When straightened , no more problems of that nature for the past 8 yrs, ...though the fuel pump on engine 20 amp spade fuse has blown at start a couple times over the years since( 30 seconds to replace.)
Both the fuel pump and ECM/ECU have on-engine fuses that could have slightly iffy connections though other connectors are more likely. Don't neglect checking on-engine grounds as well . There are several at least.
Hum, fuel, air or fire. I agree with all the above; its fire. I had the same problem with one of the twin 454s/7.4s Merc in a 330 Sundancer. It was a loose wire between the key and starter. Sorry it was sometime ago so I can't be more specific. Please tell us the fix when you find it. Good Luck!
Upon reflection, I remember in my case it was an in line fuse and its container - one of those fuse holders shaped like a cylinder about 3 maybe four inches long. I replaced both of them (each engine) with a breaker.
If it does restart right away, check the fuel pick up tube in the fuel tank to be sure debris is not acting like an anti siphon check valve. Pump pulls up debris at high rpm and debris drops away when vacuum drops. Usually just a small screen filter at the tube end. If this is the problem, you may notice no problems at lower rpm.
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"Hot wire" the engine. Passing up all those 'ign kill' switches etc.
That's gonna tell you if you have a problem in the Ign Wiring.
That's gonna tell you if you have a problem in the Ign Wiring.
rbeachhouse
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Check the fuel/water Sep. Happened to me a few years ago. I changed the filter and added some startron.