Carbs leaking oil and gas mixture

[phillipdi]

Hello,

1999 Mercury 90 elpto. I think one of my carbs is leaking oil and gas. Does anyone have a ideal what I need to do. It still runs ok but when I am fishing I kept seeing gas in the water behind my motor.

 

[jsimms724]

Re: Carbs leaking oil and gas mixture

Perhaps a stuck float or needle valve? rebuild it.

 

[Maxz695]

Re: Carbs leaking oil and gas mixture

He,s right either a stuck float or un adjusted float or the needle and seats are not sealing when the carb fills. Being that this hapens with the motor down gas build up from leaking seeps onto the water leaving the gas trail. Not a hard fix if you need assistance just write back and someone can help you with the proceedure

 

[vettman]

Re: Carbs leaking oil and gas mixture

Just had to the same happen to me . Carbs were rebuilt 6 months ago , but something got in the bottom carb and prevented the float from seating properly. Took it off, blew it out and all is fine til it happens again i guess. Have filter and water seperater but still something got thru. I have a 2000 90 hp. Thanks and good luck

 

[phillipdi]

Re: Carbs leaking oil and gas mixture

Thanks

 

[phillipdi]

Re: Carbs leaking oil and gas mixture

Thanks for the advice. I went to my boat this morning and found the carbs took off the air cover and noticed when I trimmed up that oil and gas were pouring out quite fast. So that what you mean when you say I need to rebuild it. If so I would love some assistance with that procedure.

 

[phillipdi]

Re: Carbs leaking oil and gas mixture

Thanks, its good to talk to people who had the same issue. So to take the carbs off does each one come off individally. Do I just take them off, take them apart and spray some carb cleaner in it and then hook em back up. Or should I just take it to the shop and have it done?

 

[colding]

Re: Carbs leaking oil and gas mixture

If you're taking them off anyway, go ahead and buy the parts kit for the rebuild. You get new floats, needle and seats and all new gaskets. Once you have them off, disassemble them and soak them for awhile in carb cleaner (assuming you don't have plastic-bodied carbs). Put the new parts/gaskets in and you should be golden. Not a difficult job.

If you do have plastic carbs/plastic float bowls, be sure to check if the float bowls are warped and not making a good seal.

 

[vettman]

Re: Carbs leaking oil and gas mixture

I would also replace all the carb hoses and any other hoses and lines that you can get to. My hoses were clamped with special plastic tie wraps that you can get an any marine shop. As said above , soaking and blowing them out is the best cure.

 

[phillipdi]

Re: Carbs leaking oil and gas mixture

I will do that. Last question is oil and gas supposed to leak out of the carbs when it is trimmed up, is this normal?

 

[phillipdi]

Re: Carbs leaking oil and gas mixture

Thanks for the advice I will order a rebuild kit and go for it. I will let you know how it turns out.

 

[phillipdi]

Re: Carbs leaking oil and gas mixture

Here is the status. I rebuilt the carbs today placed them back on my motor. Have a hard time getting the bottom carb on. Started my boat it reved up and then died. It kept doing that. What do I do now? Also the second and third carb is still leaking gas and oil. Could it be sucking air somewhere?

 

[vettman]

Re: Carbs leaking oil and gas mixture

Are you sure you took the time to do everything properly? Seems Sunday morning post you were ordering kits and at 7:00 pm they are totally done and put back on. Maybe they needed to soak a little longer to be sure they got cleaned well. Did you use compressed air to blow all the tiny passages out, put new hoses and maybe new inline filter on? If it is dying could be fuel pump problems.

 

[Maxz695]

Re: Carbs leaking oil and gas mixture

If the thrird carb is still leaking then it wasn,t done right. If new needles and seats where not installed then install them now.The float level my not be set correctly as well. Check all old hoses for pin hole cracks as well as the filter. When was the last time you changed the fuel pump diaphram and gaskets? if there no good the pump won,t work and the engine will start after priming it and then die out. Be aware that you said gas was leaking from the engine into the water that may mean there is a leak eleswhere on the fuel system too.

 

[phillipdi]

Re: Carbs leaking oil and gas mixture

Hello I have never change the fuel pump diaphram and gaskets. But I took off the carbs again opened them up and had a buddy show and help me adjust the needles and float level. I bought a new in line fuel filter. I put it back together cranked it and it started but only when I pushed in the choke, it used to start with having to choke it and this time the fuel bulb is rock hard. It kept dying like last time but this time when I cranked it, it did not revv up viciously as last time. I kept starting it and then started adjusting the carb screws ( the one on the side that is golden looking). I guess what I am trying to say is I am trying to sync the carbs. Now its running without dying but not how its supposed to sound. Also, when I trimmed it up gas is still comming out of the carbs, but at least I got it running. Is it safe to take on the water now? I ran out of daylight so tomorrow after work I will try to sync the carbs better. Is there anything else to do. I might replace the fuel pump as well. Thanks for your help

 

[Maxz695]

Re: Carbs leaking oil and gas mixture

turn the air mixture screw out from a light seat 1 1/2 turns start the engine and adjust it until you here the engine start to faulter or pop. screw it back in about a 1/4 turn and then adjust it for the best runing point then turn back in a hair or two. Do this on all carbs. Then recheck again to see if there close to sounding good

 

[Jiggz]

Re: Carbs leaking oil and gas mixture

Fuel-Oil mix leaking out of carbs when engine is fully tilted up is normal. This is because the float is designed only to stop fuel flow into the bowl when the engine is on the vertical. When placed in an angle the fuel will overflow to the main jets or to the atmospheric vent. As for the idle mixture screw (brass screw with spring) turn it clockwise (CW) until lightly seated (do not over tight or force or you will damage the needle). Back it (CCW) 1 1/8 full turns from lightly seated. Do this to all carbs. Now try starting the engine and it should idle at 1000~1100 RPM in neutral. If not set the idle screw adjustment (NOT THE IDLE MIXTURE SCREW)to achieve this idle speed. THE IDLE SCREW IS LOCATED AT THE BOTTOM OF THE TIMING TOWER.

 

[vettman]

Re: Carbs leaking oil and gas mixture

My mechanic says carbs should be adjusted with boat in gear tied to a dock, or on trailer with boat in the water creating an " under load condition". Throttle just at idle position,or slightly more.

 

[phillipdi]

Re: Carbs leaking oil and gas mixture

Gentlemen, I did what you said I have the idle almost where I want it. I am going to test it in the water tomorrow. But with mickey mouse ears it seems ok. Is the fuel pump bulb supposed to stay hard, because yesterday mine was hard and this evening, but it seemed like once I started syncing carbs it went soft. Is that something to be concerned with or is that normal? I pumped it again a few mins ago I can hear the gas swishing in the bulb but no hardness. Thanks for all of your guy's help!

 

[Maxz695]

Re: Carbs leaking oil and gas mixture

Make sure the bulb is the right size for the line from the tank to the quick disconnect. Any different size lines or primer bulb fittings will affect the required flow of the gas. It also may mean getting a new bulb. Esspecially if it,s an atwood. I recommened if you can afford it to buy an OEM Mercury fuel line with the primer bulb that is the correct diamiter for the fitting on the engine