trouble starting merc 5.0 efi

[Squab]

okay so here's my new is problem. I had a merc 5.0 EFI which was running fine last week. Since then the only thing I have done differently was put 10 gallons of gas from a local Exxon gas station along with star bright. When I went to start it today it wouldn't start without me giving it throttle I did get it to run at 1000 rpm but it ideled pretty rough. I haven't change the spark plugs this year and haven't had a chance to check the fuel water separator any ideas?

 

[Bondo]

Re: trouble starting merc 5.9 efi

Re: trouble starting merc 5.9 efi

okay so here's my new is problem. I had a merc 5.0 EFI which was running fine last week. Since then the only thing I have done differently was put 10 gallons of gas from a local Exxon gas station along with star bright. When I went to start it today it wouldn't start without me giving it throttle I did get it to run at 1000 rpm but it ideled pretty rough. I haven't change the spark plugs this year and haven't had a chance to check the fuel water separator any ideas?

Ayuh,.... Start with lookin' at the Contents of the fuel filter,....

 

[Fun Times]

Re: trouble starting merc 5.9 efi

Re: trouble starting merc 5.9 efi

Hi there! Do you by chance have your engine serial number handy due to I am unsure of what engine model or year you have there. The title says 5.9 which mercruiser does not have then you mentioned you had a 5.0 EFI??? Thanks.

 

[Squab]

Re: trouble starting merc 5.9 efi

Re: trouble starting merc 5.9 efi

just another thing that I noticed when I opened the fuel cap I heard air rushing almost as if it was a closed system. I know that's not true because of the vent. if there is a clog in the vent could that make my engine run sluggish

 

[Squab]

Re: trouble starting merc 5.9 efi

Re: trouble starting merc 5.9 efi

okay so I just dumped a fuel filter and there is nothing in there that would lead me to believe it is a fuel problem no water separation no gunk. Gonna put new plugs in. And see what happens. my question is why would it be running fine last week and now been running sluggish? I've also attached a picture of the fuel

 

[camalot]

Re: trouble starting merc 5.9 efi

Re: trouble starting merc 5.9 efi

it's your "air idle control valve" quite a common problem!!!

 

[MikDee]

Re: trouble starting merc 5.9 efi

Re: trouble starting merc 5.9 efi

just another thing that I noticed when I opened the fuel cap I heard a Russian almost as if it was a closed system. I know that's not true because the vent if there is a clog in the vent hood that make my engine run sluggish

You found a Russian in the gas tank? Was he a Russian tank driver? :lol:

Go with your 1st instinct here, Yes the fuel tank needs to be vented, and Yes, it can definitely affect the way your engine runs!

 

[Fishermark]

Re: trouble starting merc 5.9 efi

Re: trouble starting merc 5.9 efi

YGo with your 1st instinct here, Yes the fuel tank needs to be vented, and Yes, it can definitely affect the way your engine runs!

^^^ What he said.

If you had a vacuum in your tank when you removed the cap, then your vent hose is plugged. Try running it with the cap off and see what happens.

 

[Squab]

Re: trouble starting merc 5.0 efi

if it is such a common problem the air idle control valve, where is it located and how do I fix it

 

[alldodge]

Re: trouble starting merc 5.0 efi

if it is such a common problem the air idle control valve, where is it located and how do I fix it

The IAC is on the throttle body and it is a common problem. That being said, need your serial number to identify your engine configuration.

Are you sure you had air being sucked in or maybe was it being blown out? Warm days cause things to heat up and expand

 

[Squab]

Fuel Drip

Fuel Drip

I have a 5.0 Merc v-8 EFI. I am having a problem getting it to stay running which I am being told in a separate thread is the Air idle Valve, but while looking at the throttle body with the sir cleaner off and engine off. I noticed a drip coming out of what I can only imagine is one of the two injectors? Any ideas why?

 

[Squab]

Re: trouble starting merc 5.0 efi

serial number is 0L380350
MCM 5.0L EFI

 

[Bt Doctur]

Re: Fuel Drip

Re: Fuel Drip

The injector is bad and not sealing correctly

 

[Fun Times]

Re: Fuel Drip

Re: Fuel Drip

The injector is bad and not sealing correctly

+1, Cleaning them may work. Try a Google search on cleaning fuel injectors. There are lots of online videos that show you some ways to try it. But the best thing to do would be to remove them and send them out to an fuel injector cleaning service center.

 

[Squab]

Re: trouble starting merc 5.0 efi

Update time. Changed plugs, removed and cleaned wire to aiv and ahe runs like a top