Mercruiser 5.0 EFI cuts out

[otiscojoe]

Hi all,<br /> Have a 2002 Sea Ray 200 bowrider with a Mercruiser 5.0 260 HP EFI engine- bought new- now has 69 hours on it.<br />Runs great, but several times now while running (always above idle), the engine just dies, like the kill switch is activated. Always starts right back up with no problems.<br />Have checked all of the connections I can find behind the helm, and on the engine - yet the condition persists...<br />It has never occured at idle ( or up to 1200 rpm) , only whilst at cruising speed or above.<br />There does not seem to be any particular rpm / time when it happens, I am inclined to believe it has to do with ignition or similar, as there is no stuttering / popping etc. just dies like the switch was turned off....<br /><br />Any ideas of where I should look next? <br /><br />Thanks in advance for any suggestions.<br /><br />Regards,<br />Otiscojoe

 

[Mahoney]

Re: Mercruiser 5.0 EFI cuts out

The only time this happened to me with the same symptoms was when something was grounding itself underway. I have an older engine without all the fancy ignition cut outs and ESA's and there could be something else someone can chime in and point you too. I would ask if you recently worked on ANYTHING electronic on the boat, and go back and check those connections.

 

[tommays]

Re: Mercruiser 5.0 EFI cuts out

i would try to get it fixed becuse shutting down the motor at speed is the easyest way to get water into the cylinders and cause motor damage<br /><br /><br />with EFI it could be fuel or spark <br /><br /><br />from everything i have read here its very common to be basic things like a bad connection to the coil ect<br /><br />it may be best to let the dealer have a look as any DIY mistakes can cost a lot of money<br /><br /><br />tommays

 

[otiscojoe]

Re: Mercruiser 5.0 EFI cuts out

I would haul it out and take it to a dealer, but am hesitant because it probably won't happen when the dealer checks it out!! Or can they "plug into" these newer engines and diagnose - like the new cars?<br />I ran the boat for over 3 hours this year before the problem showed up- it just started happening the last few weeks of last season.<br /><br />How would dying at speed cause water to get into the cylinders ? It's a standard thru- hub exhaust, not through -hull.<br /><br />Thanks ,<br />Otiscojoe

 

[otiscojoe]

Re: Mercruiser 5.0 EFI cuts out

Mahoney- <br />thanks for the tip, It's usually good advise!<br />I haven't had to work ( fix problems..) on the boat ( touch wood) since I bought it.<br /><br />I did install an amplifier for the stereo, with the power cables for the amp. running directly to the batt. via standard car audio amp. cable<br />(in-lined fused) I did that several seasons ago, when the boat was new- but I'll double check that, although it has died while the stereo was playing, and I never heard it drop out or anything.<br /><br />I'm leaning towards a short or loose connection,just not that familiar with the new engines. It's quite oddd that it will start immediately back up , and run like nothing happened- i can't seem to get any repeatability with the problem to start tracking it down.<br /><br />Otiscojoe

 

[steinjo]

Re: Mercruiser 5.0 EFI cuts out

I just had the same thing happen and it happened to be the check valve on the fuel tank. <br /><br />It would run great until it picked up debris in the tank and then it would stall. After the suction was released (after stalling) the debris would settle back and it ran great until next round.

 

[mikebc]

Re: Mercruiser 5.0 EFI cuts out

It's most likely your lanyard, even if you don't wear it they go bad. Take it out and either replace it or disconnect it to see if that's your issue, but that's my bet.

 

[bobder41]

Re: Mercruiser 5.0 EFI cuts out

I dont know if this will help, i have a 95 5.0, it ran great, one day runnnig a 2800 rpm motor stopped cold in its tracks. It wouldn't restart. took it in to a dealer and it cranked right up. took it out and it did it again. after getting out the manual I noticed the factory had a second tach output. Found it on the harness running on top of the intake manifold with the factory warping (tape) undone. the wire at speed would touch the maifold and ground out the ing. system. Taped it up again and never had a reoccurance since. I would try looking for something simular next i would check the fuel system<br />bob

 

[Reel Poor]

Re: Mercruiser 5.0 EFI cuts out

Next time out, while the boat is running properly, and up on plane, give it the wiggle test. Wiggle every thing in, on, and around the wiring harness, also wiggle the key in the ignition switch, lanyard safety switch,ect,ect.<br />Try to duplicate the problem.<br /><br />A thorough wiggle test may show suspect.

 

[otiscojoe]

Re: Mercruiser 5.0 EFI cuts out

Thanks to all for the suggestions, I'm gonna have a real good second look at all of the connections, and give the wiggle test while underway a go, although I'm not sure if I can have the engine hatch open enough to access the connections back there at planing speed.<br /><br />I can also "jumper out" the lanyard switch, to take it out of the circuit- <br /><br />As far as the fuel pick -up / check valve goes, I'm not sure if the boats fitted with one or not, there is what appears to be a solenoid shut off valve in the fuel supply line just upstream of the water seperator filter.<br /><br />I'll report back my findings, hopefully I can track this down and get it sortedout!!<br /><br />Otiscojoe

 

[sugarsand_man]

Re: Mercruiser 5.0 EFI cuts out

I also had the same problem on a 2003 240 EFI and thought it was water in the fuel last year, drained the gas tank and put in fresh fuel and a racor water separator this year and 1/2 mile down the river it did it again. I took it to the dealer and they found nothing on the computer. They said they "played with the grounds" and changed the plugs and $240 later I was back in the water schepitcal. However it stopped cutting out like that but I don't get topspeed of 52 MPH like I did last year. It tops out at 43 now. After a couple more rides/hours at top speed I can hear it try to quit out a little but it doesn't do it as bad as before. I will try the wiggle test and didn't think about the lanyard key. I was thinking about buying the manual to get handle on where all the grounds are since it is pretty tight in the compartment. I am real concerned about losing 10mph off my topend and was thinking of trying high octane but I keep reading 87 is best in 2 stokes but I usually put 93 in my jet skiis with no problems. Any suggestions appreciated.

 

[dc7730]

Re: Mercruiser 5.0 EFI cuts out

This is the exact problem I have with my 2002 5.0 and it has done it since new, i have 120 hours on it now and it seems do do it more often, so the problem is getting worse, whith that said if anyone has an answer I'm listening. you can email me direct with dc7730@yahoo.com