2003 Mercruiser 5.0 EFI wont start

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OBX Sailor

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2003 mercruiser 5.0 EFI 260 hp. Engine cranks, wont start. I have fuel pressure,fuel in tank, and spark at plugs. new batteries, charged fully.
Yesterday my mechanic looked it over, he was not sure of the problem. I spayed Starting fluid in the air cleaner, and got it to start up and run for awhile. Today, it wont start even with the starting fluid.



Any suggestions for troubleshooting?
 
Bondo

Bondo

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Re: 2003 Mercruiser 5.0 EFI wont start

Any suggestions for troubleshooting?
Click to expand...

Ayuh,.....

It takes Fuel, Fire, Compression,+ at the right Time.......

You're Missing 1 of them.......
 
Don S

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Re: 2003 Mercruiser 5.0 EFI wont start

How did you check the fuel pressure, and what was the pressure on both pump?
 
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newport dave

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Re: 2003 Mercruiser 5.0 EFI wont start

You really need to connect a scan tool to even begin to troubleshoot a newer (ECM555) engine. Did your tech do that? Can you give anymore info than that?

Anyway, Two problem areas for that engine are the distributor cap and rotor which tend to corrode, and the crankshaft sensor which sits on the front/bottom of the engine and can get wet.
 
O

OBX Sailor

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Re: 2003 Mercruiser 5.0 EFI wont start

I will check the distributor and cap today. Had them replaced last spring.
Does anyone sell the scan tool? I have a OBDII reader, is it the same?

I dont know what the fuel PSI is, but is sqirting fuel at the rail valve. When it did start , it ran fine, no missing, studder etc.
 
O

OBX Sailor

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Re: 2003 Mercruiser 5.0 EFI wont start

I changed the distributor cap and rotor today. Fired right up. I checked it several times and it runs fine. Always check behind your mechanic, it seems mine didnt change these as I requested in the spring tune up!!!
Thanks to all.
Ray
 
Don S

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Re: 2003 Mercruiser 5.0 EFI wont start

I can't post a .pdf document here, but if you PM me your email address, I will send you service bulletin 2003-06 about problems with moisture in the cap. Sounds like it may be your problem now, and will continue to be a problem.

PS: Here is the Rinda Tech Mate that works well for checking codes and seeing how things work while the engine is running.
Not as fast as a DDT or the computer. But it will perform most functions to allow you to test your engine.

http://216.230.203.183/marine/mtspec.htm
 
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OBX Sailor

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Re: 2003 Mercruiser 5.0 EFI wont start

My email is
I would like to read this info and thanks for your assistance!
Ray
 
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Don S

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Re: 2003 Mercruiser 5.0 EFI wont start

If you use the PM (Private Message) area of the forum, you won't have your email address showing for all the spammers out there to collect.
I will send you the service bulletin and edit out your email address.
 
Don S

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Re: 2003 Mercruiser 5.0 EFI wont start

For anyone else wanting to know if the bulletin relates to their engine or not, Here are the SN's involved.
Mercruiser DOES NOT go by year. Only SN.

MCM V6 4.3L MPI 0M322781-0M645782
MCM V8 5.0L MPI 0M320415-0M642305
MCM V8 350 MPI 0M320590-0M642305
MCM V8 MX 6.2 MPI 0M320614-0M642305
MIE 350 MPI Tow Sports 0M310010-0M391684
MIE 350 MPI Inboard 0M310001-0M391684
MIE MX 6.2 MPI Inboard 0M310008-0M391737
 
JustJason

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Re: 2003 Mercruiser 5.0 EFI wont start

I'm not sure if i've seen that bulletin yet don. If you ever have an actual moment that your not super busy could you PM it to me :) ;) :) ? thanks!!
 
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eastern27

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Re: 2003 Mercruiser 5.0 EFI wont start

Don S said:
For anyone else wanting to know if the bulletin relates to their engine or not, Here are the SN's involved.
Mercruiser DOES NOT go by year. Only SN.

MCM V6 4.3L MPI 0M322781-0M645782
MCM V8 5.0L MPI 0M320415-0M642305
MCM V8 350 MPI 0M320590-0M642305
MCM V8 MX 6.2 MPI 0M320614-0M642305
MIE 350 MPI Tow Sports 0M310010-0M391684
MIE 350 MPI Inboard 0M310001-0M391684
MIE MX 6.2 MPI Inboard 0M310008-0M391737
Click to expand...
What is the difference between OM and OW serial numbers? I checked the tags in my owners manual and they start with OW. It's a 2005 , 350 MPI Horizon, Bravo II.
 
Don S

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Re: 2003 Mercruiser 5.0 EFI wont start

OW means it was newer. The problem was fixed before the OW's even started into production.
 
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OBX Sailor

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Re: 2003 Mercruiser 5.0 EFI wont start

Thanks to all for the help. The boat is running fine now!
OBX Sailor
 
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donzi 18

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Re: 2003 Mercruiser 5.0 EFI wont start

Hmm, I'm having same problem with a 2006 mx 6.2 that fits the serial #'s of the ones with problems. :mad: replaced the fuel filters yesterday and all it does is crank with nobody home might try the cap a rotor today. Is there a long term fix for moisture in the cap or is this just something that I'll be dealing with again later? thanks Steve
 
Bondo

Bondo

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Re: 2003 Mercruiser 5.0 EFI wont start

donzi 18 said:
Hmm, I'm having same problem with a 2006 mx 6.2 that fits the serial #'s of the ones with problems. :mad: replaced the fuel filters yesterday and all it does is crank with nobody home might try the cap a rotor today. Is there a long term fix for moisture in the cap or is this just something that I'll be dealing with again later? thanks Steve
Click to expand...

Ayuh,.......

Welcome Aboard there Donzi,.......

1st off,.....
Posting Your Problem onto somebodyelse's Old thread is a No- No,.....
Start your own thread,.... You'll get More,+ Better responses......
Post All the Info you can about it,+ We'll All be focused on Your Problem, rather than this 1.....

Btw,..... This still applies,..... Which 1 are You missing,..??..??
Ayuh,.....

It takes Fuel, Fire, Compression,+ at the right Time.......

You're Missing 1 of them.......
Click to expand...
 
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