03 mercruiser 5.0 (GM) TBI Won't stay running???

[White Wizzard]

I have an 03 Crownline 230br with an EFI (TBI) GM 5.0L. Engine is freshly rebuilt and has the following parts new: coolant temp sensor, iac, fuel pump, both injectors, regulator, plugs, cap and rotor. Fuel system had a bunch of water in it. Sucked all the water/fuel out and filled back up with fresh fuel. Boat starts right up and runs for about 10 seconds and then acts like it runs out of gas. You can keep it going by giving it more gas, but will still die eventually. Had some venting issues with the tank, but they are fixed and still same problem. When it finally dies a little bit of "smoke" puffs out of the flame arrestor. Any suggestions would be greatly appriciated.

 

[smarks]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

From the sounds of things, it sounds like it's running out of fuel and going lean before dying. Double check your filters.

 

[White Wizzard]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

It's on its second filter one of which was this evening when it was doing the dying.

 

[White Wizzard]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

bump

 

[White Wizzard]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

ttt

 

[White Wizzard]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

anyone else have any idea?

 

[Bondo]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

It's on its second filter one of which was this evening when it was doing the dying.

Ayuh,... Did you examine the contents of the 1st,..?? Water,..?? Crud,..??

Boat starts right up and runs for about 10 seconds and then acts like it runs out of gas.

Is the fuelpump wired through an oil pressure switch,..??
Is the switch Workin',..??

 

[White Wizzard]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

First filter had a lot of crap and water. Second one just a little bit of h2o. Pulled filter off just to check again and there was no water. I believe there is an oil preasure switch, but not sure how it correlates with the pump. I figured it wouldn't event run if there is no oil pres. Even if it did would it run sometimes for up to 20 seconds before just dieing? I am no boat mechanic so I don't know.

Also when it dies it makes a sucking sound like shhhhhhhhhhhooop. I know that's horrible, but I don't know how else to describe it.

 

[Bondo]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

I believe there is an oil preasure switch, but not sure how it correlates with the pump.

The fuelpump is powered by the igntion circuit,..
It goes Through the o/p switch to power the pump...
No oil pressure the pumps stops, the motor quits,... a Safety feature...
If the switch is Beat,... It don't run...

During Starting, the pump is powered from the starter..., Not through the switch...

 

[White Wizzard]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

I understand the concept. I just thought that if it was the oil switch it would shut off at the same time everytime and not run 5 sec one time and 20 sec the next, but again I am just guessing.

 

[Bondo]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

but again I am just guessing.

Ayuh,.... Sooo am I,.... I'm not there....

 

[White Wizzard]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

Thanks

 

[Dshow]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

I don't have the manual for that engine handy (thanks Merc!) but I have a 2001 TBI engine and the fuel pump is controlled the the MEFI control module. The control module may read the oil pressure switch and turn on/off the fuel pump accordingly, but I don't believe it is wired directly in the circuit.

 

[White Wizzard]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

is there any test i can do on the pres switch? Maybe a certain ohm reading?

 

[fossill]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

Get a merc manual and follow the diagnostic/trouobleshooting charts which should lead you to the issue. You will also need the diagnostic tools involved. With EFI systems especially, you are are wasting time and money by guessing what the problem is.

 

[phillyg]

Re: 03 mercruiser 5.0 (GM) TBI Won't stay running???

Since the motor is recently rebuilt I suppose there could be a lot of reasons why you're having this problem. However, my recent experience with a new 2004 5.0 TBI motor with about 100hrs was with the idle air control motor. It's a $112 Mercruiser part that's located on the throttle body.

My motor started to cut out while in gear at low speed and at idle. If I disengaged the throttle I could get it to re-start and run the rpms up with no problem. The motor ran well at cruising speed, too. I replaced the part and it runs fine. It's a fairly expensive part to replace if something else is the problem. Easy off/on part with two hex bolts and one electrical connection.

Caveat: I'm not a mechanic and I took the advice of others on these forums.