Evinrude Carb Job gone bad?

[rustyscrew]

My 1993 or 94 Evinrude 120 HP engine was acting up on each start. It would crank over and start running then lose cylinders and finally stall. If I kept starting it, it would eventually run OK. SO I decided it was time to put in some new carb kits...especially since I knew one o-ring was broken from last time I cleaned them.

I did that today. I have done this a dozen times using the same parts except I replaced pins on a couple occasions. This time I replaced all the gaskets, the pins, the seats, everything. I was looking forward to a nice start and it is WORSE! Way worse. Sounds like its running on a couple cylinders. Will not idle, but I can keep it going at higher throttle. Carbs seemed good. No leaks, and holds the fuel pressure.

I checked the plugs. They were fouled black so I cleaned them up and replaced them. They turned black pretty quickly again. I checked electricity to the plugs and that is good. I am stumped.

So here are some possibilities-

In each carb kit, their was a red small round gasket. I didn't see where that would go. Maybe behind the high-speed jet? I didn't pull that out. There was no gasket beneath the seat so I didn't put one in. Should I have?....It looked like the float was at a bad angle if I did. Also, there was a little ruler in each kit....should I be doing something with that?

I have never had to tinker with adjustments or anything before. I can't imagine why I would this time just because I replaced some parts.....

So the big question here is...does that sound like a carb problem before I going pulling all 4 off again? I was considering replacing the pins and seats with the old ones.

Any thoughts would be greatly appreciated!

thanks

 

[Brianjason6]

Re: Evinrude Carb Job gone bad?

Is it possible that your fresh carbs are now working perfectly? And that's the problem? Maybe the problem was in the fuel system to start with. I know nothing about your motor but since you've done nothing but improve the carbs it causes me to think the fuel filter or screen in the tank could be stopping up. May have even caused you to do all of the previous cleanings.

I watched this happen to my father in law. He cleaned the tank out completely, changed the filter, and back to new. Also gained 10mph.

 

[Brianjason6]

Re: Evinrude Carb Job gone bad?

Just to add..after re-reading your post...I've never seen a seat that didn't get a gasket behind it. The ruler is probably for setting your float. Hopefully someone can tell you on here, or you may find it in your kit info, how to set the float.

 

[jonesg]

Re: Evinrude Carb Job gone bad?

Is it possible that your fresh carbs are now working perfectly? And that's the problem? .

exactly what I was thinking, it might make sense to do a spark gap test, set the gap to 3/8th inch on a gap tester from an auto store, $12 tool.
You cannot use spark plug to test for spark. It needs to jump a BIG gap.

 

[rustyscrew]

Re: Evinrude Carb Job gone bad?

Thanks for the replies. I went back in and pulled all the carbs off, replaced the seats and pins with the old pins that really don't look bad at all. Fired it up and STILL running bad. I am thinking it is not the carbs after all.

I had tested the spark with a proper tool. So the plugs are getting electricity.
Compression is ok.

Port side plugs get a dry black soot on them pretty quickly. Stbd side plugs are wet.

It seems to me it is not fuel starved but getting a bad mix or bad spark.

I am going to replace the plugs and spin on filter (already replaced inline).
Then run it off good clean fuel and see how that works....beyond that I think I am SOL!

Still open to any thoughts on this problem!

thanks
rusty

 

[14ftgrumman]

Re: Evinrude Carb Job gone bad?

Pullout the jets, clean and blow out with compressed air.

If it was running ok before you went thru the carbs an dnow it's running worse, then it must be in something you did, not a pre-existing problem.

Remove the carbs, dissassemble, soak overnight in carb cleaner and rebuild according to specs. Including set float levels.