More Merc 120 Problems (update!!!)

[brunowren]

Ok I posted the other day about my 75 Tropicana with a 120 mercCruiser that was dieing on acceleration... <br /><br />Well I went to the dealer to buy a new Carb <br />(instead of fooling with the old one) The dealer pulled out the Fuel filter and the idiot that had it before put the filter in backwards.....<br /><br />Dealer said well here is your problem! And I didnt buy the carb...<br /><br />Well took it out today! Ran great for a few min.. Then started acting up... Started acting like it did on Sunday..<br /><br />Die on Throttle. would hardly idle right...<br /><br />So what would due this after the engine warms up?<br /><br />I asked the dealer about the hot air choke if it would get stuck and he said no! But it is a fuel issue...<br /><br /><br />Please Help ME <br /><br />Has NewFuel Pump / Line from tank to pump is new<br /><br />I am ready just to buy a new carb if I cant figure this out

 

[jeff13601]

Re: More Merc 120 Problems (update!!!)

I dont remember the post. Has it been tuned up, clean gas, anti syphone checked, pickup tube screen and water seperater?

 

[wake5150]

Re: More Merc 120 Problems (update!!!)

I read your other post and would like more detailed information about how the boat runs. As much detail as you can provide.<br /><br />I.e.<br />1) Does it idle ok when you first start it (cold)<br />2) Does it idle ok after it's warmed up?<br />3) Describe 1/2 throttle behavior when cold.<br />4) Describe 1/2 throttle behavior when warm.<br /><br />I assume you have one of these Rochester 2bbl carbs<br />1351-4263A, 1351-5202A, 1351-6065A 2 <br /><br />If you have 3 or 4 hours spread over 3 days, I would consider just rebuilding the carb. Those 2 bbls are super easy to rebuild for someone with moderate mechanical skills.<br /><br />The overhaul kit for that carb is $22 from Doug Russell<br />1397-2637 OVERHAUL KIT 1 $21.82 <br /><br />If you're considering buying a new carb, then there's no harm in trying to rebuild your current one. You'll be surprised how easy it is to do.

 

[Don S]

Re: More Merc 120 Problems (update!!!)

I would guess from your discription, plus your other post that you may have a problem on your fuel pickup tube in the fuel tank. There is a screen on the tube that is probably plugged up due to lots of "Gunk" in the fuel tank. Once you start it, it sucks up more till the engine dies. If the screen is missing, check the antisiphon valve. Same thing is happening.

 

[brunowren]

Re: More Merc 120 Problems (update!!!)

Ok I think I found the culprit ! <br />Take a look at this<br /> http://photobucket.com/albums/v646/brunowren/Boat/ <br /><br />Pulled the pickup out and it was all crusty and that looks like some sort of screen on the bottom ... But man how could anything get in there ? <br /><br />Have all must all the gas drained and the tank out of the boat...<br /><br />What is the best way to flush out the inside ?? Water(I doubt it) , Kerosene ??? I might actually be able to go this weekend <br /><br /><br />Thanks for all your help guys !!!!

 

[jeff13601]

Re: More Merc 120 Problems (update!!!)

Looks like a little varnish. I would drain the tank, swish it out a couple times with gas to get out rust pieces etc and put on a new tube and screen

 

[wake5150]

Re: More Merc 120 Problems (update!!!)

I bow down to Don S. He is the King. I was sure it was a Carb issue. <br /><br />Looks like Bruno will be On the Water this weekend.<br /><br />Wake

 

[jeff13601]

Re: More Merc 120 Problems (update!!!)

I could have sworn that earlier in this post I mentioned the pickup tube screen. But I will admit that Don is the man 99 percent of the time.....

 

[brunowren]

Re: More Merc 120 Problems (update!!!)

You are all the Man !!! Thanks to everyone.. I just figured lets start and the beginning and pulled the tank and was gonna go from there! <br /><br />Dealer didnt have new pick up.. Told me to clean it could and I could just cut off the screen and install a in line fuel filter out side the tank... What do you think

 

[jeff13601]

Re: More Merc 120 Problems (update!!!)

I think it would probably be ok but there would probably be a chance of a piece of rust holding the anti syphone valve open. Cant you take a piece of screen and fasten it over the end of the tube?. Don has a lot of links and he might have one on a place where you might be able to order one

 

[brunowren]

Re: More Merc 120 Problems (update!!!)

yea I guess I could use a piece of screen and the new fuel filter just for added measure... Where is this anti siphon valve at ?

 

[Mahoney]

Re: More Merc 120 Problems (update!!!)

Anti siphon valve is screwed into the fitting at the top of the tank that feeds your engine fuel. I removed my tank , drained everything out, and swiched it around good with a gallon of denatured alcohol. You will be amazed at the crap that comes out of the tank.

 

[brunowren]

Re: More Merc 120 Problems (update!!!)

OOO ok Just looked like a regular old brass fitting.. Yea I cant wait to clean it out and see what kinda sludge I get out... <br /><br /><br />Also the 10 gallons I siphoned out looked fine and is new just put in Sunday... Is that ok to put back in ?

 

[jeff13601]

Re: More Merc 120 Problems (update!!!)

Do you have a riding lawnmower. Thats where I used mine. The crap is going to be on the bottom. I suppose if you put it through a screen you could use it but I would make sure that I burned the most of it before I put in fresh

 

[brunowren]

Re: More Merc 120 Problems (update!!!)

Ok I got the tank empty OMG !! what a soup of crap.... I could hear stuff banging around inside so I took out the Fuel sending unit... It was one big rust rod !!! the float had fallen off.....<br /><br />Well needless to say I am picking up a new sending unit tomm.. Have rinsed the tank a few times and it is all coming out clear now <br /><br />I think I am almost there