5.0 Alpha quits after 40 seconds

[dunga]

I have a 1998 5.0 Alpha in a 1998 Chaparral 2130. The engine has 200 hours. I just installed #1 battery and have a #2 battery which was installed from previous owner. Cleaned all the cables which took of the power off the boat. The battery switch works fine. Off,1,All,and 2 . Will start easily and runs great for approx. 40 seconds and quits. Temp, oil , voltage all remain normal. I have checked removed and drained the fuel water separator and reinstalled. Thought it was maybe the alternator over charging. So I isolated the alternator and ran on only battery. No change still quits after 40 seconds. The only thing I have done different was install the new battery.<br />Is there any type of reset switch that needs to be reset after removing power from the boat? Or do you have any ideas.<br /><br />Thanks for your time,<br /><br />Bruce Goldring<br />FLA

 

[vinney]

Re: 5.0 Alpha quits after 40 seconds

Has the boat been stored any length of time. It sounds like a fuel problem. Gummed up carb or a bad electric fuel pump. If it has been stored was there fuel stablizer added to the fuel. If not pull and clean the carb. If it has been stored correctly you need to check the fuel pressure and check power/cycle of electric fuel pump.

 

[dunga]

Re: 5.0 Alpha quits after 40 seconds

Boat was run just last week. No problems. The only change was the battery thing. I also did pull the fuel pump conection wire from the engine to see if the pump was working, the engine started but only ran for a second. Plugged back in and same problem only ran for 40 seconds. So I know the pump works.

 

[vinney]

Re: 5.0 Alpha quits after 40 seconds

Put a test light on the fuel pump wires and see if the 12 volts stays on with the key. I would still check fuel pressure. If your sure the fuel pressure ok then put the test light on the purple wire on the engine(coil or electric choke) and make sure the 12 volts stays on with the key on. Purple wire is key on voltage.

 

[dunga]

Re: 5.0 Alpha quits after 40 seconds

OK but I just wonder why the engine will run for 40 seconds at all throttle settings? The fuel pressure should effect those higher throttle settings shouldn't it?

 

[dunga]

Re: 5.0 Alpha quits after 40 seconds

fuel pump and igntion check out. But that battery wire off the alternator is very hot to touch? Do not know if the engine has an auto shutdown if it senses something out of tolerance hence the hot wire?

 

[vinney]

Re: 5.0 Alpha quits after 40 seconds

No It doesnt. Did you hook up a battery cable backwards.

 

[outboardguy]

Re: 5.0 Alpha quits after 40 seconds

There is a oil pressure switch just above the oil filter with a purple wire going in and a purple wire going out.It shuts off the power to the fuel pump when the engine loses oil pressure. The key thing is that there is also a bypass circuit run off of the starter.So every time you crank on it the fuel pump works off of the bypass to give it the fuel to run 40 seconds,but when you let the key out of the crank position it depends on the oil pressure circuit for power from then on.If the switch is broken it won't run long.I would verify good oil pressure first,then make a jumper to jump the switch.If it now works good then order a new switch.Don't run the engine for any extended period with the oil pressure switch bypassed.

 

[dunga]

Re: 5.0 Alpha quits after 40 seconds

The oil pressure switch was the problem..It was very rusted up and was shorting out hence the hot wire off the alternator. I checked it by jumping the wires. The engine ran without shutting down and the wire did not get hot...<br />Thanks you very much

 

[dunga]

Re: 5.0 Alpha quits after 40 seconds

WELL I thought it was the problem...It ran well today and after shut down for a few hours , I went to start again and shuts down 40 seconds later again..The alternator is very hot now and not the orange wire I am also was reading erratic RPMs when it wasrunning earlier. There has got to be some short somewhere or the alternator is bad???? Leaning troward