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Mercruiser 5.0L I/O carbureted engine fails to start, but starts w/ starting fluid , then stops

R

rinkerroger

New member
Last used my 2002 Rinker Captiva 212 w/ merc 5.0L carb. engine 3 weeks ago and a few times prior to that in last couple months w/ NO problems or symptoms. Off-loaded boat into water and lowered outdrive ( I turned on the ignition so I could monitor the lowering of the outdrive, I remember there was no audible alarm as is usual ). With drive down, pushed neutral button in and throttle forward to start position, and turned the key to start. Boat turned over strong, but no quick easy start as is typical. After repeated attempts and pumping the throttle to full w/ no success, --- fellow boater provided starting fluid. After spraying 2-3 seconds into the spark arrester, 2 sec. pause, turned key and boat fired right up strong and easy, and died a few seconds later as the fluid was consumed. Additional attempts to start w/o starting fluid were fruitless, and with starting fluid started easily but then died.

Unscrewed fuel line at carburetor and no gas or even smell of gas present. We did not notice the customary hum when turning the key on at any time. Last time out boat had been Island hopping a few times before being trailered home. At home used muffs to flush the saltwater out no problem, always shut off water before shutting down engine.

First thought was electric fuel pump, not sure how to isolate and test. 2nd thought is low oil pressure fuel pump sensor switch, and 3rd is that lack of alarm at ignition /key in "on" position. I'm handy but not good w/ electrical tester. What do I do first? Second? HELP?
 
1 get rid of the starting fluid
2 your carbd, so you dont have the prime from an ecm
3 you should never hear the pump run when you turn the key to "on"
4 you dont need the key for the trim, thats hooked directly to the battery
Locate the oil pressure switch then tempy jump the wires together with a paperclip, wire, etc. with key on, pump must run
 
If with pump verified running you still don't get fuel to the carb, check antisiphon valve on fuel tank outlet, possible it is stuck shut and not allowing fuel to pump.
 
....IFSO, antisiphon valves are a replace, not repair part usually located at the fuel tank. I know this is obvious, but is the manual fuel shut off turned on?
 
i wasn't aware there is a fuel shutoff valve. nevertheless, i didn't change anything since the boat last ran perfectly fine. thanks for your reply. for future reference, where would this cut-off be?
 
Removed the plug from the low oil sensor and jumped with paperclip, turned on ignition and could positively hear hum from the fuel pump. Tried to start, unsuccessful -- but didn't turn it over two long, conserving battery
a rinker dealer said to look for a fuse block near ther ECM on the port side of the port bank. cant see one. he does have an older 1998 rinker though.

I see what may be a relay near the ecm. has a black plastic cover that just lifts off, showing two posts w/ cables. at the bottom of one side are a couple additional smaller connectors w/ wiring leading into the main harness. I know I replaced this once before, quite a few years ago, don't remember exactly what the symptom was at the time. That and replacing a cracked trim reseervoir are all I have had to do since I bought the 3 yr old boat back in 2005. Could this thing be my problem again? Any way to jump to easy test?
 
Since the fuel pump ran, I removed the fuel line at carb and got no gas out when turning over and I presume pump is running while cranking, when done cranking, can still hear the pump humming. I see by a couple receipts I did replace a SIE 18-5801 solenoid in 2016. I think that is the piece I referred to in the previous note w/ two posts.

I simply don't see a small fuse block

How would I check the antisyphon valve, Do I have to remove the large 2.5 in diameter fuel filler line at the tank?
 
dont have a pressurized fuel tank to try that, best i could do would be to buy a fitting to screw into carb, attach a rubber or plastic tubing to place on fitting and put some gas in a funnel leading into the tubing. sounds klugee to me. but thanks.

so if i've got this right, I turn on the key and power goes through a relay to starter, starter initially powers the fuel pump, and after several turns of the engine, oil pressure is generated that pressurizes the low oil pressure sensor which "closes?" a circuit that now allows current to power the fuel pump as long as the engine runs. so is this relay the culprit? we topped off the tank the day before attempted use w/ approx. 10 gallons of gas. i haven't changed the fuel separator recently but have never really found a issue from water in the fuel, it has mostly always run. Doesnt the starting of the engine on starting fluid accomplish the same thing? as the alternate fuel tank?
 
rinkerroger said:
dont have a pressurized fuel tank to try that,



the starting of the engine on starting fluid accomplish the same thing? as the alternate fuel tank?
Click to expand...

You do not need a pressurized fuel tank, All you need is a gas can and a length of fuel line. Disconnect the fuel line at the filter Hose barb and connect a length of fuel line. Put the other end in a gas can. You can use an outboard primer bulb to prime the pump. If all is fine and the engine starts you have an issue with the fuel line to the pick up in the tank. BTW the electric lift pump will not prime itself.


Starting fluid just showed you that ignition is present and gasoline is not.
 
There is no barb to attach a hose to, the fuel filter is male into carb and female receiving the metal fuel line fitting.

I have gained a lot of insight to the complexities of my engine and the electrical/sensor side that is designed to protect the engine. Maybe I'll invest in a manual to pour over if there is a future problem.

For now though, I took it to a boat repair shop today. I like being able to provide my own repairs, just not equipped at this time.
thanks to everyone who contributed.
 
you must have a rubber fuel line from the tank to the engine, remove that hose and attach remote tank where it connects at the engine. There is no fuel filter on the pressurized side of any fuel pump
 
...................
rinkerroger said:
......................., best i could do would be to buy a fitting to screw into carb, attach a rubber or plastic tubing to place on fitting and put some gas in a funnel leading into the tubing. sounds klugee to me. but thanks.
Yes, klugee at best!


so if i've got this right, I turn on the key and power goes through a relay to starter, starter initially powers the fuel pump,
Not quite!
The starter motor's solenoid circuit momentarily powers the fuel pump's relay.
The relay continues to power the fuel pump until the starter motor solenoid circuit becomes disengaged.
That is when the N/O LOP switch closes and takes over in the presence of oil pressure.

and after several turns of the engine, oil pressure is generated that pressurizes the low oil pressure sensor which "closes?" a circuit that now allows current to power the fuel pump as long as the engine runs.
Basically correct!

so is this relay the culprit?
That is possible. You would need to test it!

we topped off the tank the day before attempted use w/ approx. 10 gallons of gas. i haven't changed the fuel separator recently but have never really found a issue from water in the fuel, it has mostly always run. Doesnt the starting of the engine on starting fluid accomplish the same thing? as the alternate fuel tank?
Use caution when using starting fluid.
Use small amounts only.
FYI.... Gumout 5072866 is specifically designed for use in gasoline engines.


As for using an alternate or external fuel tank, if you suspect that you have a main fuel tank issue regarding the dip tube, dip tube screen, anti-siphon valve, hoses, main filter, etc. , why not explore those areas and take care of them if need be?
Ultimately, you will end up correcting any issues there anyway!
Click to expand...



.
 
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o2batsea said:
PCK, he already bailed out and took it to a shop. Try to keep up.
Click to expand...

you can't make it up... rick I am copying your words from another thread , I think I'm getting an honorable mention ...


Some members are apparently skimming through these threads without having fully read or comprehending the content. As a result, misunderstandings and conflicts shortly follow. This has recently occurred in a thread where both Dieter and I have participated.
It would benefit the forum if we were to all read the entire content (fully and comprehensively) before responding!


To the OP please post the finds from your mechanic so we can close this out
 
PCK is typical,.
Someone with all the answers (mostly very long winded spew) but rarely offers valuable/specific solutions!!
 
ok guys, thanks for all the interest. Got the Banana Boat back and took it out to run in the gulf Saturday, ran around from Clearwater, FL to Honeymoon Island, and then back south through the Intercoastal all the to John's Pass at the north end of St. Pete Beach and back to Clearwater,..... just livin the life! Happy to have left Cincinnati.

Boat runs fine now. They tested and found no current on a "purple wire" back in the engine area. Found supposedly a loose fuel filter fitting which is why there was gas in the bilge, ( only I have never previuosly had gas in the bilge and NEVER a smell of gas under the sundeck covering the motor) strange???!!!!
Second, the no current issue led them to pull the dash panel( just one for all gauges), and they said my wiring was all fried and melted together in areas. They showed/ and gave me the wiring harness they had to cut/remove ( I asked for that stuff). I guess they bought a couple harnesses and basically cut them into mine. That was it, problem solved. I asked for the burnt up pieces because this seemed odd that everything on the dash worked except for the cigarette lighter plug-in. I mean, the engine turned over, the outdrive went up and down, the lights still worked, the horn sounded, the fuel registered, trim gauge worked, bilge worked,--------I'm wondering how all that worked ? They would not get any points for their clean up, but it led me to accept maybe it was as they said. There were a few little insulation pieces left in the boat, and what kind of looked like soldering droplet discolorations in a couple spots. They suggested that the cig plugin may have caused significant damage long ago(stopped working 4-5 yrs, ago; thats maybe why there was no odor to the wire harness they showed/gave to me) and just now rubbed through another wire causing a problem. I don't know. I wonder if they caused the wire fry when they pulled the dash? I did smell the wiring and there was no odor! I always thought that wiring insulation that had been burned/ melted badly would continue smelling beyond a couple days. Got boat back in two days, They had five stars in reviews, cost me $497.50. about $115 in parts/ materials, did not list harnesses, just 25 ft blk wire and 4ft red wire. Sound like a plausable explanation from them to you guys? or did I get taken?
 
The boats working now so yes very plausible and doesn't seem like price is out of line. Really lucky was gas leaking into bilge that there wasn't a fire
 
No you got the problem sorted for roughly 3 hours of their time and some random parts. I believe the dash fire story as production boats use really cheap wiring and they're installed by people who are trained to install quickly not necessarily the best way. Since the engine running is not determined by gauges and warning bells, it's perfectly possible that your dash could burn up and it would still start and run. it's the key switch that provides engine run voltage by way of the main relay.
Honestly tho, the solder connections are worrisome as this is not ABYC standard to use solder connections anywhere in marine wiring. There are several reasons why not and I won't bother with the details, but I would consider this "fix" of the dash to be a short term thing and eventually hire a marine electrician with excellent references to redo the whole mess. It's money well spent to have it sorted and when you see what a really good electrician will do to your wiring it's like wow.
Have him/her look at your batteries and charging system while they're at it. As you have already dodged a rather large bullet ( instead of blowing you straight to smithereens, the engine simply failed to operate...whew! gas in the bilge is bu hao) take this as a sign from above that you need to spend the coin to make it right.
 
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o2batsea said:
No you got the problem sorted for roughly 3 hours of their time and some random parts. I believe the dash fire story as production boats use really cheap wiring and they're installed by people who are trained to install quickly not necessarily the best way. Since the engine running is not determined by gauges and warning bells, it's perfectly possible that your dash could burn up and it would still start and run. it's the key switch that provides engine run voltage by way of the main relay.
Honestly tho, the solder connections are worrisome as this is not ABYC standard to use solder connections anywhere in marine wiring. There are several reasons why not and I won't bother with the details, but I would consider this "fix" of the dash to be a short term thing and eventually hire a marine electrician with excellent references to redo the whole mess. It's money well spent to have it sorted and when you see what a really good electrician will do to your wiring it's like wow.
Have him/her look at your batteries and charging system while they're at it. As you have already dodged a rather large bullet ( instead of blowing you straight to smithereens, the engine simply failed to operate...whew! gas in the bilge is bu hao) take this as a sign from above that you need to spend the coin to make it right.
Click to expand...


If the mechanic soldered the wires ( a no-no, as pointed out), you need to find out if they did the other no-no, insulating the resulting splices with electrician's ( vinyl) tape. The correct way to splice wires is with crimp butt insulated splice connectors of the correct gauge size. Shrink insulation types are the preferred type. They aren't inexpensive.
 
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