2002 mercruiser bravo 3 cranks and won't start

B

Bob McDonough

Member
Jun 18, 2015
39
Bass River, Cape Cod
Boat Info
2002 Sea Ray Weekender / LUNA Sea 3
Engines
Mercruiser with Bravo 3 out drive
I hope all are well and having a great boating season.

I need some advice on a starting issue. The problem originated I beleive from bad fuel and as a result plugs looked like a need for a change. I have a 2002 SeaRay weekender powered by a mercruiser 5.0 bravo 3. I pumped old fuel out and replaced plugs. Engine started (in driveway). Went to launch and had a hard time turning over. Placed in slip, next time out cranked and would not turn. Changed water/fuel seperated a couple of squirts of starting fluid and started 1st turn. Now it is back to cranking and not starting. Not sure about seperator, it is a 25 micron. Should it be different like a 10? Any other ideas would be appreciated.

Thank you in advance,

Bob McD
 
What fuel delivery system do you have ? Probably still have water in the tank. How did you get the old fuel out ?
 
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I am not sure of fuel system I have. Frankly never gave it a thought. Should not have been water in tank though as I used a small electric fuel pump and removed sending unit and sucked everything out with a extension to reach far edges of tank.
 
Couple of squirts of starting fluid is the only hint your offering up. Got an engine # ? Carb, EFI, MPI, ??
 
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It is 5.0L MPI; engine OM325771. The only other thing I can include is it did sit for a few weeks while I was traveling. I can not put my finger on anything else that would cause a sudden change. I am also not a mechanic and I say that with all due respect. It is a rareaty to find a good, honest marine mechanic on cape cod these days. I could tell you stories that reflects on this industry badly. So I try to read as much as I can and Understand but as I said no mechanic here. Tell me what kind of house you want built and that is another story.
 
Bob, when you used the starter fluid, how long did the engine run? Did it start and run any times after using the fluid?

I'm pretty sure the standard FW separator is 25 micron. Yes, you could use a finer one, but I don't think this is your problem. You have the spin-on style filter which is good - easy to deal with. Just to verify/eliminate that water isn't your issue (again, I don't think it is) you can dump the filter into a glass jar (spaghetti) and observe the gas for separation/cloudiness.

Try this... advance the throttle about 1/3 to 1/2 and try starting. Just be ready to pull it back so you don't rev to high. If it runs smoothly at about 1,500-2,000 RPMS in neutral, then pull the throttle back to idle speed. Your symptoms are indicative of a common problem, the IAC (Idle Air Control) valve. It does exactly what it's name implies - allows proper starting and idling. Once you get past relative idle speed, it no longer has any impact. If, when you pull the throttle back to idle, the engine dies - it's most likely your IAC acting up.

Often, you'd get some warning beeps once the engine is running, but you may have an older-style computer and I'm not sure if it's going to tell you right away about the IAC (I'm not sure on this one, though). BUT, the engine would need to be running to do this.
 
When I used the starting fluid the 1st time it stayed running. That was before I left for a few weeks. When I tried again and it wouldn't start, I used the starting fluid again. A few times it almost started. In fear of killing batteries I have talking with folks and researching problem. I will try what you sudgest and will follow up.
thanks for taking the time to help!
 
Just another quick thought... When you first turn the key ON (not start), can you hear the fuel pump run?
 
If you have an interest in fixing this yourself go to mercruiserparts.com and punch in your engine #. A Quick look shows that you have a second fuel filter on that engine. Could be plugged up. Autozone will let you use a fuel pressure gauge. If changing out the second filter doesn't work, you want to check fuel pressure at the rail.
 
When I turn the key to the on position i wait a second or two as i do hear what I will assume is the pump. Were you thinking bad pump?
 
Bob McDonough said:
When I turn the key to the on position i wait a second or two as i do hear what I will assume is the pump. Were you thinking bad pump?
Click to expand...

Just narrowing down possibilities/variables. On that line of thinking, next in line would be to check pressure at rail. If pressure is good, you can likely eliminate everything upstream.
 
Any News on this?
I have a 2007 260SD with the 350MPI, doing the same thing. I have fuel at the rail and pressure of 43PSI, new injectors, new plugs and wires. Will start and then immediately die. If I use starter fluid it will stay running on the fluid. Checked the injectors with a Noid light, have signal, just wonder if it is at the right time... News on what your fix was might help..
 
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