help with mercruiser 5.0L !

slothman

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Re: help with mercruiser 5.0L !

update: I inspected the dist. cap, it looked fine. Cleaned the contacts on it. The rotor looked fine. The coil looks original and the insides look oily/greasy. resistance was off so I'm just gonna replace it. might be pulling the carb soon to inspect it.
 

slothman

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Re: help with mercruiser 5.0L !

well so far this is what I've done: new coil, plugs, fuel pump, anti-siphon, and fuel line. I guess the next step is to rebuild the carb. Already got the rebuild kit ordered. After this I am not sure what's going on....I'm out of ideas.
 

CaptainMak

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Re: help with mercruiser 5.0L !

update: I inspected the dist. cap, it looked fine. Cleaned the contacts on it. The rotor looked fine. The coil looks original and the insides look oily/greasy. resistance was off so I'm just gonna replace it. might be pulling the carb soon to inspect it.

You're gonna skimp out on getting a $20 cap/rotor kit while you have absolutely no idea when a tune-up was done on this engine ? Replace 'em even if they DO look "ok" to you.

And yes, you definitely need your carb re-done.
 

slothman

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Re: help with mercruiser 5.0L !

You're gonna skimp out on getting a $20 cap/rotor kit while you have absolutely no idea when a tune-up was done on this engine ? Replace 'em even if they DO look "ok" to you.

And yes, you definitely need your carb re-done.

It's not a spark issue. As soon as I pump the throttle I can see the gas squirting in. It'll start for a split second and then die.
 

CaptainMak

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Re: help with mercruiser 5.0L !

It's not a spark issue. As soon as I pump the throttle I can see the gas squirting in. It'll start for a split second and then die.

I stated you need your carb re-done, I didn't say it was a plug issue. As far as replacin' the cap/rotor, it's up to you. Seems strange to skip doing it for such a low cost investment.
 

slothman

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Re: help with mercruiser 5.0L !

I stated you need your carb re-done, I didn't say it was a plug issue. As far as replacin' the cap/rotor, it's up to you. Seems strange to skip doing it for such a low cost investment.

I will do a full tune up once the motor is running. At this point I am still doing process of elimination.
 

slothman

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Re: help with mercruiser 5.0L !

update: finally got time to pull the carb. The inside was NASTY, yellow green goop every where. Venturi holes are plugged. I'll finish rebuilding it tonight and hopefully she fires right up ....
 

slothman

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Re: help with mercruiser 5.0L !

I'm really stumped now. Rebuilt the carb and still no start without pooring gas down the carb. Where do I start now?
 

hivoltg

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Re: help with mercruiser 5.0L !

I still think you have a carb issue. Mixture screws, floats, and all that adjusted to specs?

Can you get fuel to spray from that carb with pumping the throttle if you manually fill the float bowl brass vent?
 
Last edited:

achris

More fish than mountain goat
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Re: help with mercruiser 5.0L !

Did you soak the carb overnight in cleaner? Did you then blow ALL the passages out with dry compressed air (from a compressor, not just a supermarket tin)?
 

slothman

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Re: help with mercruiser 5.0L !

yes I have rebuilt many carbs before, everything is adjusted correctly and nice and clean. Unless there is so much crap in the gas that it plugged itself again. I'm going to pull the filter and see what it looks like.
 

tank1949

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Re: help with mercruiser 5.0L !

yes I have rebuilt many carbs before, everything is adjusted correctly and nice and clean. Unless there is so much crap in the gas that it plugged itself again. I'm going to pull the filter and see what it looks like.


Not real sure if you have anti-syphon valves in fuel line. You may want to check. I experience old crap in fuel too. I removed pick up tube and removed strainer in tube so that I could recycle big crap into spin on filter and clean tank best I could. I suggest over treating existing fuel if you suspect it is realy old and recycling fuel with electric fuel pump or electric transfer pump. Good luck!
 

slothman

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Re: help with mercruiser 5.0L !

I pulled the screen filter from the carb and it was CAKED with gunk ! I pumped some of the fuel into a clear bucket and some of it was ORANGE. It had two layers of gas. Most definitely dirty fuel with water. I think the fuel sat for too long with the previous owner, and then when I filled it up with fresh fuel it just stirred up the junk inside the tank. I'm going to get this gas out !
 

tank1949

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Re: help with mercruiser 5.0L !

Get a gal of acetone. It will desolve a lot and recycle old gas/ace mix. But, be sure to take out pick up screen in tubes to assist in recycling gas. Good luck! Been there.
 
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