rough/no idle

[xjcj3a]

1997 evinrude 115hp intruder 60 degree heads.


My issue is this, the boat starts revs up and down. but just doesnt idle, while running it sounds rough. when i take the boat from the water, i see that the bottom cylinders have fuel coming out of the carbs, not a ton of fuel but definitely not correct. I have been able to get it to run and idle if i pull the plugs, dry them and let the motor sit uncovered for a few hours.

I have tested the spark, spark plugs all fire. Mostly a white with light blue spark.

I have tested the power packs, all have a .1 reading when tested for lead wire to ground. and a .5 i believe it was reading from lead post to spark plug wire post.

the carbs do not leak fuel when tilted. just after it trys to run.

at this point i dont know what to test or do, any thoughts are greatly appreciated. Motor ran fine 2 weeks ago in the morning, but turned to crap in the afternoon. Thank you for your time.

 

[Bosunsmate]

Re: rough/no idle

It might be the inlet reeds for that cylinder failing

 

[Bob_VT]

Re: rough/no idle

Clean, service and rebuild the carbs.

 

[xjcj3a]

Re: rough/no idle

I am unfamiliar with inlet reeds what and where are they?

 

[Watermann]

Re: rough/no idle

I would agree with Bob, you should do some carb cleaning and rebuilds, could be the float valves are sticking and allowing the fuel to continue pouring in.

 

[Bosunsmate]

Re: rough/no idle

If it doesnt leak fuel when tilted like this- engine is off and the primer bulb stays firm then the reeds are the smalll metal fins just behind the carbs. If gunk is in there or one is snapped fuel will dribble back out of the affected carb at idle but not at medium to high rpm

 

[xjcj3a]

Re: rough/no idle

More info. The ball does not stay hard. It softens over time. The bottom two carbs when pumping the ball fuel is flowing into the barrel of the carb. I swapped top and bottom carbs same thing fuel only seeps into the barrel on the bottom. So throttle body warped? Maybe just needs a thicker gasket? Would reeds affect this? Seems like I'm nattowing the issue down just unsure what the cause is

 

[Chris1956]

Re: rough/no idle

Reeds are not a candidate for your issue at this moment. Get your carbs cleaned up and new gaskets, inlet needle and seats and floats. Set the floats properly. Now retest.

The reed valves are flaps of stainless steel that act as one way valves, allowing fuel and air to enter the crankcase, but not exit into the carbs.

 

[xjcj3a]

Re: rough/no idle

more information,

issue is not at the throttle body and carb gasket. it is leaking in the throttle body where the butterfly valve goes through. like theres a seal inside that that is leaking. any information on that? is it rebuildable?

 

[Chris1956]

Re: rough/no idle

If tyou have liquid fuel in the carb throats, the float is not shutting off the fuel flow to the carb bowl. Clean and rebuild the carbs with new gaskets, floats and inlet needle and seat.

 

[xjcj3a]

Re: rough/no idle

It is not coming from the carb itself it is flowing from past the carb where the throttle body butterfly's sit. I have moved carbs around issue doesn't follow carb it stays on the same cylinder. If it was the needle then it should follow the carb correct?

 

[Bosunsmate]

Re: rough/no idle

It still could be as the pressure in bottom carb will be slightly more than the top one, try adjusting the float to close the needle a bit sooner

 

[Chris1956]

Re: rough/no idle

Well, the enrichment primer injects fuel into the intake manifold. Maybe it is stuck open or in manual position?

 

[Bosunsmate]

Re: rough/no idle

Well, the enrichment primer injects fuel into the intake manifold. Maybe it is stuck open or in manual position?

That a reply about as good as it gets,
I totally agree

 

[xjcj3a]

Re: rough/no idle

how would i check that? where would it be located?

 

[Bosunsmate]

Re: rough/no idle

Pull the primer lines from the carbs. The primer is normally a little black barrel with a red switch on top of it note which way that switch is pointing.
You can just pull the bottom one to check if its the problem

 

[xjcj3a]

Re: rough/no idle

carbs have no lines going to them, the fuel travels through the throttle bodies into the carbs

 

[Bosunsmate]

Re: rough/no idle

It should have a choke solenoid have you found that?

 

[xjcj3a]

Re: rough/no idle

Carbs have no lines or electrical items on them. Float is the only thing they moves in the carb. Everything else is on the throttle bodies.

 

[Chris1956]

Re: rough/no idle

Look for the primer lines to the intake manifolds. There should be on on each manny. Pull them off and crank the motor. If fuel comes out of them, the primer is providing it. That may be the issue.