1999 EFI 5.0 mercruiser random stalls and no starts

[Egriff]

Hey everyone really in a bind and trying to find out some ways to get this problem fixed. I bought this boat last year and it ran great all year without a single problem. Had it winterized and stored indoors and took it to the lake for the first time this year today and it ran great for about ten minutes and then just died and would not restart. After it cooled down for a while it started back up again and ran fine for about 5-10 minutes and stalled again I was able to restart this time but the idle was horrible and then it would come out of it and run for a minute and stall out again. Until it got to the point where it would not fire again and had to be towed back to the dock. I have replaced the fuel filter at the end of last year and I am going to do it again as the problem does appear to be fuel related as the injectors were not pulsing at all but when I got home I threw a set of ear muffs on it and it fired right up like nothing was wrong but after a minute or so it started sputtering and shut down on me again with no alarm signals at all. I removed the flame arrestor and have no fuel coming out of the injectors at all at this point during cranking and was wondering where a good place to start would be. My family and I are going on vacation in 3 weeks and I would really like to have this fixed by then. I do not currently have the serial numbers on the motor but I will post them tomorrow. I have reviewed multiple posts for the similar problems but there are so many different diagnosis that I don't know where to start any help I could get with this would be greatly appreciated.


Thank you
Ed

 

[Fun Times]

Re: 1999 EFI 5.0 mercruiser random stalls and no starts

I removed the flame arrestor and have no fuel coming out of the injectors at all at this point during cranking and was wondering where a good place to start would be.

Hi there, Next time the above quote happens, take note of the tachometer (rpm gauge) to see if your getting about 300+ RPM at cranking speed. Also if possible have a timing light hooked up to the high tension coil wire to observe whether or not your getting a continuous flash/spark.

With this system, If it's not a fuel system issue then it very well could be an ignition problem that would shutdown the fuel flow out of the two TBI injectors like mentioned.

You will also need Mercruiser fuel pressure tee test fitting part number 91-806901 to test fuel pressure between the fuel line and the TBI unit.

Like you mentioned, we'll need your serial number to find the correct service manual and fuel pressure specifications for your engine model if needed.

 

[NHGuy]

Re: 1999 EFI 5.0 mercruiser random stalls and no starts

Also, try the simple step of getting a glass jar and pouring the contents of the fuel water separator in it. Check for debris and water in there. And replace the separator.
If there's water or junk in there, get it out, Remove all the tank contents and either toss it or process it to remove all the impurities.
Some folks call processing out the junk "polishing" your fuel. It is merely running it through filters repeatedly til it's clear of the unwanted junk. Beats tossing it out and you end up with some extra fuel jugs.
If it is absolutely ruined you will know, if it smells like varnish instead of fuel just find a way to recycle it.
If the fuel is good, and there is every possibility that it is, continue on with Fun Times approach. If the fuel is dirty you may need to do both the fuel and check the engine too.

 

[Egriff]

Re: 1999 EFI 5.0 mercruiser random stalls and no starts

Ok so the number I have located on the block is L618551 I watched the tach during crank and it really doesnt appear to be miving at all however engine is cranking over very well did remove the distributor cap and find a small amount of rust on the hold down screw for what I believe to be the ignition module so going to clean that up and see if it helps any other tests you could help me out with would be great

 

[Egriff]

Re: 1999 EFI 5.0 mercruiser random stalls and no starts

Also not trying to sound like an idiot how does the rotor come out of the distributor I have looked and it appears that it would pop right off like any normal car but it doesnt appear to budge when I try to remove it

 

[Bondo]

Re: 1999 EFI 5.0 mercruiser random stalls and no starts

Also not trying to sound like an idiot how does the rotor come out of the distributor I have looked and it appears that it would pop right off like any normal car but it doesnt appear to budge when I try to remove it

Ayuh,.... Welcome Aboard,... For some unknown reason, Merc glues 'em on,....

Ya Bust it off when replacin' it,...

 

[Egriff]

Re: 1999 EFI 5.0 mercruiser random stalls and no starts

Ok was able to get the rotor off with a little help from a heat gun ignition module was original so went to local mercruiser dealer and picked up new one and low and behold it was the problem boat is running like a top now injectors are working properly and it purrs like a kitten thanks for all the help guys I truly appreciate it

 

[Fun Times]

Re: 1999 EFI 5.0 mercruiser random stalls and no starts

I watched the tach during crank and it really doesnt appear to be miving at all however engine is cranking over very well.

Ok was able to get the rotor off with a little help from a heat gun ignition module was original so went to local mercruiser dealer and picked up new one and low and behold it was the problem boat is running like a top now injectors are working properly and it purrs like a kitten thanks for all the help guys I truly appreciate it

Good job, You found and replaced one of the three items that I suspected to be wrong with your engine with all of you're descriptions above including the first post.

Let your vacation time be golden, Happy Boating!