Running VERY rich

[FJ_Russo]

I have a 1974 Evinrude 50hp. It is running extremely rich. I know all 2cycles have some unburnt gas come out of the exhaust but this looks like the BP oil spill in the lake. My bulb never gets firm and I can pump as much gas into the engine as I want. I have black unburnt gas on the back of my boat and all over the engine. What could I be looking at? Is this a carb issue? I have a couple screws on the carb heads that say something like mix adjustment on them would that be anything I should play with? Thanks guys trying to get out this weekend but well see I guess.

 

[kenmyfam]

Re: Running VERY rich

Needs a good decarb to begin with.
My 2 cents.

 

[Rick.]

Re: Running VERY rich

If your bulb never gets firm then you have one or more carbs. with needles that aren't seating. Not sure if the 50 is 2 or 3 cylinders but if you have that much fuel leaking in the lake it is going straight through the carb./s and not getting burnt. My son had a huge oil slick on the lake around his boat that wouldn't start. He was pumping the bulb and cranking the engine and it wouldn't start. I had to run down and tow them to the dock with my trusty 4 HP Evinrude. Sure felt good. His problem was a stuck needle in the carb. Best of luck. Rick.

 

[FJ_Russo]

Re: Running VERY rich

It is a 2 cylinder with 2 carbs. I was thinking the same thing maybe a stuck needle or two. I have a diagram of the carb, is that something I can just clean and that will free it up? http://www.boats.net/parts/search/BRP/EVINRUDE/1974/50473M%201974/CARBURETOR/parts.html Can someone take a look at this diagram and tell me what I need to look at cleaning to free this up? Once again thanks so much. Only had this question up for an hour and already have had some good responses!

 

[Rick.]

Re: Running VERY rich

Parts 27 will be the offenders in that hey aren't stopping gas flow but it would be wise to get a couple of kits and clean and rebuild them. It could even be caused by a water (gas in this case) logged float or improperly set float or a little debris at the seat. Rick.

 

[mikesea]

Re: Running VERY rich

It could also be the fuelpump,if you unmount the pump,squeeze the ball,if you get fuel through the pulse port on the pump ,your putting fuel into the engine via that port,if your engine has a hose that goes to the crankcase for the pulse,remove the hose from the pump and test,some fuelpumps have an acess hole in rear ,and mounting bolts secure it over the port on the block,I dont recall your eng

 

[OldNBold51]

Re: Running VERY rich

It could also be the fuelpump,if you unmount the pump,squeeze the ball,if you get fuel through the pulse port on the pump ,your putting fuel into the engine via that port,if your engine has a hose that goes to the crankcase for the pulse,remove the hose from the pump and test,some fuelpumps have an acess hole in rear ,and mounting bolts secure it over the port on the block,I dont recall your eng

Usually this much fuel into the exhaust is a sign the fuel pump diaphragm is bad as the diaphragm uses the pulse of the piston to move the diaphragm. hence, you have a spot where fuel can , if you're diaphragm has a hole in it, go straight into the exhaust stream. It's usually a huge amount of fuel like you described.

 

[FJ_Russo]

Re: Running VERY rich

I went through today and cleaned the carbs and made sure everything was moving freely. I still have a lot of unburnt fuel coming out of the exhaust. Is the diaphragm your talking about the one that sits behind the fuel filter screen? I'm not exactly sure which part your talking about. Thanks

 

[FJ_Russo]

Re: Running VERY rich

In this diagram is the part your talking about inside part #1? And is there a way to check this to see if there is a hole in it before I order the new part?