1985 merc 50, 4cyl, 2 carbs

[fishingdan]

The carbs were professionally rebuilt by a reputable shop last August. It ran great through the end of the season. <br /><br />On the second outing this year, the low end idle got a little rough and the idle speed has slowed slightly. When I push on the primer bulb, I noticed a small amount of fuel comes out of the lower carb. I suspect there is some crap in the needle valve. Is there any way to clear this without taking the carb off?<br /><br />Thanks

 

[Laddies]

Re: 1985 merc 50, 4cyl, 2 carbs

Probably varnish from winter, usally carb and fuel injecter cleaner in the gas will clean it up

 

[WillyBWright]

Re: 1985 merc 50, 4cyl, 2 carbs

So did you stabilize the gas, or are you going to have to repeat the same old repair? A stitch in time...<br /><br />I wouldn't count on gas additives. First you have to get the motor running decent. They work on cars because you drive them alot. Not usually true with boats. Plus the motor gets it's lubrication from the gas. Starving for gas? Starving for oil! You could end-up roaching a piston or two waiting for things to work thru.

 

[Laddies]

Re: 1985 merc 50, 4cyl, 2 carbs

First the carb is dripping, thats excess fuel and oil, that is not starving, secondly we have used these products since Mercury Marine made them starting in the 50s, with good success, we even use to include them in a spring commissioning as a preventive maintance thing, in most cases of idle problems they will solve about 50% Bob

 

[fishingdan]

Re: 1985 merc 50, 4cyl, 2 carbs

The fuel was stabilized. Yes, I think it is getting too much fuel. What is the name of the fuel system cleaner that I should try?<br /><br />I don't know the last time the fuel filter was cleaned or replaced. Is it similar to a auto oil filter in that it will be bypassed if it is clogged (thus letting dirt move to the carbs)?

 

[WillyBWright]

Re: 1985 merc 50, 4cyl, 2 carbs

Sorry, but a stuck float valve in no way guaranatees that the main jet isn't restricted. It tends to prove the Varnish theory. That, and it's not difficult to overcome the float valves with the primer bulb on those old Mercs. In fact, it's normal. I still don't like using additives in 2-strokes. Things like carb cleaners can thoroughly mess with the oil's ability to stick to the surface that it's supposed to lubricate. The only things I advise adding to two-stroke gas is the oil and stabilizer. Nothing else. Remember, Mercury makes MerCruisers and 4-stroke outboards as well. Just because it says Mercury on the label doesn't make it appropriate for everything Mercury makes.

 

[Laddies]

Re: 1985 merc 50, 4cyl, 2 carbs

Fuel stabilizer inless properly used can cause as much trouble as it is suppost to remedy, we do not recommened it to our customers and will only use it if they bring it in and instruct us to. I beleive that it's just another way to seperate the customer and his money, we lived without it for many years, just a personal opinion, many others feel completely the opposite way. As fall as carb cleaner or conditioner, there are many good brands out there read the label and make sure it is 2 cycle safe--Bob

 

[WillyBWright]

Re: 1985 merc 50, 4cyl, 2 carbs

Laddie hit the nail on the head. Read the instructions. A lot of problems arise from the attitude "If 8oz to ten gallons is good, a quart should work 4-times faster." That's messing with fate, and sometimes it's best avoided altogether.

 

[fishingdan]

Re: 1985 merc 50, 4cyl, 2 carbs

Now I am confused, what should be the first thing that I do? <br /><br />Thanks

 

[fishingdan]

Re: 1985 merc 50, 4cyl, 2 carbs

I will use a fuel system cleaner first. What do you folks recommend for the fuel system cleaner?<br /><br />If that doesn't work, I believe I next need to look and make sure that the float needle valve isn't being prevented from closing due to some junk. Correct? <br /><br />If yes, can I remove the lower carb, clean it the float valve carefully, and reinstall it without having to go through the carb synch procedures (which I can see in the manual, but looks more involved than I am willing to take on)? <br /><br />Thanks,<br />Dan

 

[fishingdan]

Re: 1985 merc 50, 4cyl, 2 carbs

bump